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Dehiscence and fenestration in skeletal Class I, II, and III malocclusions assessed with cone-beam computed tomography
Abstract
To test the null hypothesis that the presence of dehiscence and fenestration was not different among patients with skeletal Class I, II, and III malocclusions.
In this retrospective study, a total of 123 cone-beam computed tomography (CBCT) images were obtained with an iCAT scanner (Imaging Sciences International, Hatfield, Pa). Patients with normal vertical patterns were classified according to dental malocclusion and ANB angle. Class I comprised 41 patients-21 girls and 20 boys (mean age, 22.4 ± 4.5 years); Class II comprised 42 patients-22 girls and 20 boys (mean age, 21.5 ± 4.2 years); and Class III comprised 40 subjects-22 girls and 18 boys (mean age, 22.1 ± 4.5 years). A total of 3444 teeth were evaluated. Analysis of variance and Tukey's test were used for statistical comparisons at the P < .05 level.
Statistical analysis indicated that the Class II group had a greater prevalence of fenestration than the other groups (P < .001). No difference was found in the prevalence of dehiscence among the three groups. Although fenestration had greater prevalence in the maxilla, more dehiscence was found in the mandible for all groups. In Class I, alveolar defects (dehiscence, fenestration) were matched relatively in both jaws. Furthermore, Class II and Class III subjects had more alveolar defects (41.11% and 45.02%, respectively) in the mandible. Dehiscences were seen with greater frequency in the mandibular incisors of all groups.
The null hypothesis was rejected. Significant differences in the presence of fenestration were found among subjects with skeletal Class I, Class II, and Class III malocclusions. Fenestrations had greater prevalence in the maxilla, but more dehiscences were found in the mandible.
... In malocclusion Angle class III patient exists a physiological dental compensation with the maxillary incisors with proclination and mandibular incisors with lingual inclination. This, with the reduced bony anatomy surrounding these teeth (mandibular symphysis and vestibular, lingual/palatal plate) may restrict the amount displaced during the treatment, especially if the required inclines are excessive [3]. ...
... This study provides to recognize, measure and classify through tomographic evaluation dehiscences and fenestrations in patients with skeletal malocclusion Angle class III. Previous studies [3,8,15] have reported more frequency of dehiscences and fenestrations in anterior teeth than posterior teeth, and more defects in vestibular plate than lingual plate. ...
... The patients with skeletal malocclusion Angle class III have bone characteristics which plays an important role in the development of these defects, due to the fact that they have thinner bone plates and anterior teeth tipping [3,8,10]. Kook et al. [4] and Kim et al. [18], reported greater bone resorption in mandibular plates than in maxillary plates of mandibular incisors of these patients, because their mandibular symphysis is thinner than patients with other types of malocclusion. ...
... [1,2] During tooth movement in orthodontic treatment, the bone tissue surrounding t h e a l v e o l a r r i d g e i s c o m m o n l y reshaped according to the type of tooth movement. [3] The reduction in the volume of the alveolar bone, often to a minimal thickness or even non-existent, can be a complicating factor for orthodontic treatment. [3,4] Therefore, the choice of the treatment plan should consider both bone morphology and tooth position. ...
... [3] The reduction in the volume of the alveolar bone, often to a minimal thickness or even non-existent, can be a complicating factor for orthodontic treatment. [3,4] Therefore, the choice of the treatment plan should consider both bone morphology and tooth position. The observation of each patient's anatomical details, as well as the comprehension of the dental risks and damage to the adjacent tissue, enables one to recognize the limits of orthodontic treatment and to practice orthodontics more safely. ...
... The observation of each patient's anatomical details, as well as the comprehension of the dental risks and damage to the adjacent tissue, enables one to recognize the limits of orthodontic treatment and to practice orthodontics more safely. [3] Hence, the structure and topography of the alveolar bone should be considered before planning the treatment and tooth movement, for which radiography and computed tomography (CT) exams are necessary. [5] Tooth extractions are commonly performed during orthodontic treatment, most commonly extracting the first premolars. ...
Introduction:
To evaluate, by cone-beam computed tomography (CBCT), the change in thickness and height of the alveolar bone and interdental septum in the anterior mandible after orthodontic treatment for dental crowding using tooth extraction.
Material and methods:
The sample consisted of 48 mandibular incisors from adult patients who presented with Class I malocclusion and required orthodontic treatment with the extraction of mandibular premolars. CBCT images were taken before starting the treatment (T1) and three months after treatment (T2). The following measurements were evaluated: width and height of the alveolar bone and the interdental septum, the distance between the cementoenamel junction and the bone ridges (F-CEJ-MBC and L-CEJ-MBC), as well as the vertical positioning and inclination of the incisor, using the Lingual Plane as the reference point. The paired Student's t-test and Pearson correlation were used with a significance level of 5%.
Results:
A significant increase was observed in the distance L-CEJ-MBC, which shows the appearance of bone dehiscence. The degree of dental crowding was not a risk factor for the development of dehiscence. The decrease in the incisor inclination and intrusion was related to the formation of dehiscence on the lingual surface.
Conclusion:
The variation in the incisor's inclination and intrusion during the treatment of dental crowding using tooth extraction are related to the formation of bone dehiscence on its lingual surface.
... In addition to the suggested benefits listed above, this philosophy argues that the light force produced by the system allows the connective tissue and alveolar bone to follow tooth movement, and therefore, more expansion of the maxillary arch can be achieved. 19,20 The other advantages of the Damon system include shortening of the chair time and the treatment time and increased patient comfort and oral hygiene. 3,7,19 Considering all these advantages and disadvantages of these treatment methods and also the suitability of the case, camouflage treatment with the Damon system was planned in this case. ...
... 1,12 The possible disadvantages of this braces system are: the bracket system is inadequate to correct rotations, using self-ligated bracket systems in the border non-extraction patients may cause dehiscences, and fenestrations due to insufficient bone thickness and proper torque control can be challenging with light nickel-titanium wires. 5,18,20 The 2 important factors for treatment with premolar extraction were crowding greater According to Howe's model analysis, at the beginning of the treatment, the distance between the premolars and the apical bone base width decreased in both the maxilla (−4.9 mm/−2.9 mm) and mandibula (−6.3 mm/−5.2 ...
... However, according to current literature, it may be useful for dental volumetric tomography to examine the presence of dehiscence and fenestration on the root surfaces. [3][4][5]20 Retrochelie superior was seen according to S line (−2 mm) at the beginning of the treatment. An improvement in soft tissue profile was achieved with the upper lip supported by the protrusion of the incisors, but no change was obtained in the patient's mandibular asymmetry. ...
Abstract
This case report presents the camouflage treatment of an adult patient with skeletal class III malocclusion and severe crowding who was treated with a passive self-ligating bracket system. A 15-year-old female patient presented with a chief complaint of asymmetric and concave profile due to mandibular prognathism and retrusive upper lip with severe maxillary and mandibular crowding and anterior crossbite. The treatment plan included double jaw orthognathic surgery for the correction of skeletal class III malocclusion and man- dibular laterognathia. However, the patient refused this option because of surgical risks and costs. Since the patient did not have a very severe asymmetry and it was tolerable by the soft tissues, it was decided to apply camouflage treatment. Considering the patient’s severe crowding, a self-ligating bracket system (the Damon Q-passive self-ligating system—“0.022 × 0.028’’ slot; Ormco, Glendora, Calif, USA) was used for camouflage treatment. The basic foundation of the Damon System and the low friction between the Damon brackets and the wide super-elastic CuNiTi (Damon arc form-Ormco) wires create the optimum force to initiate tooth movement. This light and physiological force accelerates tooth movement, and dental arches are shaped by the expansion of the posterior teeth rather than the inclination of the incisors through “lip bumper effect” of m.orbicularis oris and m.mentalis. As a result, it has been claimed that the Damon system eliminates extraction in medium and severe crowding cases. Also, bodily buccal movement of the posterior teeth provides apposition at buccal alveolar bone.3-6 At the end of the treatment, the patient was functionally and aesthetically optimized, had the anterior crossbite corrected, and had solved severe crowding without extraction.
Keywords: Self-ligating bracket, camouflage treatment, severe crowding
... Fenestrations and dehiscences are found in patients without orthodontic treatment. 1 Many studies have examined the prevalence of alveolar defects during orthodontic treatment. [2][3][4][5][6] showed that there is more dehiscences in hyperdivergent than hypodivergent patients. ...
... 6 In general, dehiscences are more frequent in the mandible and fenestrations in the maxilla. 1,6,7 Surgically Assisted Rapid Palatal Expansion (SARPE) is indicated for skeletally mature patients with severe maxillary transverse deficiency, with crowding, with a wide buccal corridor and failure of conventional maxillary expansion (RPE). 8 This surgical orthodontic treatment evolved from cuts in maxillary resistance areas to LeFort I osteotomy with or without pterygoid disjunction to decrease pressure against the teeth that would affect the cortical bone and prevent periodontal defects. ...
... If the bone defect did not involve the alveolar crest, it was classified as fenestrations ( Fig 4B). 1,6,7 Evaluations were performed in dark room to improve the visualization of alveolar defects, 6 but also those who could be potential confounders, such as age and sex. All statistical analyses were performed using Alveolar defects increased to 96.5% at T 2 and 100% at T 3 . ...
Introduction:
Surgically Assisted Rapid Palatal Expansion (SARPE) promote maxillary expansion in skeletally mature patients. This technique is effective; however, some side effects are still unknown.
Objectives:
evaluate the presence of alveolar defects (dehiscences and fenestrations) in patients submitted to the SARPE. The null hypothesis tested was: SARPE does not influence the number of dehiscences and fenestrationss.
Methods:
A retrospective quasi-experiment study of a convenience sample of 279 maxillary teeth, in 29 patients evaluated with Cone Beam Computed Tomography (CBCT) at T1 (before SARPE), T2 (after expansion) and T3 (after retention), was performed. The examined teeth were: canines, first and second premolars, first and second molars. in axial, coronal, and cross-sectional views. The evaluations involved viewing slices from mesial to distal of the buccal roots.
Results:
All statistical analyses were performed using SAS 9.3 and SUDAAN softwares. Alpha used in the study was 0.05. Alveolar defects increased statistically from T1 (69.0%) to T2 (96.5%) and T3 (100%). Dehiscences increased 195% (Relative Risk 2.95) at the end of expansion (T2). After retention (T3), individuals were on average 4.34 times more likely to develop dehiscences (334% increase). Fenestrations did not increase from T1 to T2 (p = 0.0162, 7.9%) and decreased from T2 to T3 (p = 0.0259, 4.3%). Presence of fenestrations at T1 was a significant predictor for the development of dehiscences in T2 and T3. Dehiscences increased significantly in all teeth, except second molars.
Conclusion:
The null hypothesis was rejected. After SARPE the number of dehiscences increased and fenestrations decreased. Previous alveolar defects were predictor for dehiscences after SARPE.
... respectively. In 2012, Yagci A et al. [19] studied 41 Class I, 42 Class II, and 40 Class III patients, and found that alveolar bone dehiscence had the highest prevalence in the lower jaw of Class III patients (42.64%), while alveolar bone fenestration had the highest prevalence in the upper jaw of Class II patients (19.49%). In 2013, Sun L et al. [20] studied 44 cases of skeletal Class III malocclusion and found that the prevalence of alveolar bone dehiscence and fenestration was 61.57% and 31.93%, ...
... Since alveolar bone dehiscence and fenestration began to receive academic attention, their prevalence has been continuously studied due to their close association with gingival recession and the risk of orthodontic treatment [12][13][14][15]. These studies [1][2][3][4][5][6][7][8][9][10][11][19][20][21][22][23] can be divided into dry skull studies and CBCT studies, and include samples covering all types of malocclusions. There are systematic differences between dry skull studies and CBCT studies. ...
... In dry skull studies, the prevalence of dehiscence ranged from 0.99 to 13.4%, while the prevalence of fenestration ranged from 0.23 to 16.9% [11]. In CBCT studies, the prevalence of dehiscence ranged from 27.07 to 61.57%, while the prevalence of fenestration ranged from 3.06 to 36.51% [18][19][20][21][22][23]. Those studies confirmed that alveolar bone dehiscence and fenestration were widespread in the population. ...
Objectives
The purpose of this study was to investigate the prevalence of alveolar bone dehiscence and fenestration of Class I individuals with normality patterns in the anterior region using cone-beam computed tomography (CBCT).
Materials and methods
A total of 4715 retrospective cases from January 2018 to December 2020 in the Orthodontic Department of xxx Hospital were screened. Sixty-one cases were Class I individuals with normality patterns in the anterior region. Their incidence of dehiscence and fenestration in the anterior teeth region was studied and statistically analyzed.
Results
Dehiscence was found in 27.46% of the evaluated anterior teeth and fenestration was found in 26.91% of anterior teeth. Severe dehiscences and fenestrations mainly occurred in mandibular canines and maxillary canines, respectively. Alveolar bone defects were present in 100% of patients, while one patient had alveolar bone defects in 91.67% of the anterior teeth.
Conclusions
Dehiscence was found in 27.46% of the anterior teeth of Class I individuals with normality patterns, while fenestration was found in 26.91% of them. Alveolar bone defects were present in 100% of patients.
Clinical relevance
Alveolar bone dehiscence and fenestration were normal and common in our sample, indicating that they are more likely to be physiological rather than pathological defects. Orthodontists should be aware of the presence and severity of these defects before treatment in order to avoid both possible complications and overtreatment.
... They found a favorable correlation between the incisors' increased labial and total alveolar bone thickness and the retraction pace, change in inclination, and extent of incursion. [6][7][8] An essential component in defining the limits of tooth movement in alveolar bone. Unwanted orthodontic side effects, including as external root resorption, gingival recession, bone dehiscence, and fenestration, are likely to happen when the root travels past the alveolus and makes contact with the cortical bone. ...
... As a result, tooth movement needs to be done carefully. [6][7][8][9][10][11][12] Thus aim of the present study is to identify anatomic relationship between central incisor roots and alveolar bone thickness in individuals with variable sagittal malocclusions. ...
The predisposition of central-incisors and its association with alveolar bone in surrounding area required assessment before any decision for treatment which involves anteroposterior (AP) movement of incisor inside the jaws.
To identify anatomic relationship between central incisor roots and alveolar bone thickness in individuals with variable sagittal malocclusions and to also correlate if any sexual dimorphism among samples.
The present study was conducted on 100 pre-treatment lateral cephalograms of young adult patients aged 15 to 30 years. They were divided into 2 groups on the basis of Angle’s system of classification as Class I and Class II with 50 subjects each group. patients were selected from the pool of patients who reported to All the lateral cephalograms were hand traced by same operator and tracings included mandibular symphysis, 1 molar central incisors, the OP, incisal edges, root apices, incisor long axes, upper incisor CEJ and upper incisor root midpoint. Various parameters were then measured for both the groups. All data were analysed using the Statistical Package for the Social Sciences software (SPSS version 24.0 Inc, Chicago, IL, USA. Independent sample t-test was used to determine possible statistically significant differences between the Class I and Class II for various parameters.
U1-lab was statistically significant increased value in Class I sample, Where as L1-ling was statistically significant increased value in Class II sample. A very small but significant difference was found for the mandibular alveolar bone thickness in males and females in both Class I and Class II samples.
A significant variance between alveolar (AV) process of class II and Class I occlusion. There was also a significant variation in males and females of the sample group.
... However, another study found that the incidence of apical fenestrations is more common in the first premolars in cadavers of South African black people [22]. Generally, apical fenestrations are more frequent in the maxilla than in the mandible [23]. The results of the present study agree with the outcomes of all these studies, in which apical fenestrations were more frequent in the first molars and first premolars (Figure 3), in addition to being more frequent in the upper teeth than the lower (Table 1). ...
... The incidence of apical fenestrations is affected by diverse factors, including malocclusion, as a positive correlation was found between apical fenestration and the presence of skeletal Class I, II, and III malocclusions in 123 patients (males and females) in a Turkish population [23], besides other physiological and pathological factors [26]. In the present study, it was found that there was a negative correlation between the presence of apical fenestration and the mesial inclination, rotation, and extrusion of the upper teeth, in which lower percentages of these teeth positions were associated with the presence of apical fenestration in the upper teeth with a statistically significant difference with the scores MI0, RO0, and EX0 (p ≤ 0.05). ...
This study aimed to assess the relationship between apical fenestration—a defect in the alveolar bone involving the root apex—and tooth position in all tooth groups, excluding the third molars, utilizing cone-beam computed tomography (CBCT) images. A total of 800 CBCT scans (400 maxillary and 400 mandibular) from patients undergoing various treatments were examined by a single professional (radiologist and endodontist). Statistical analyses, including the chi-square test or Fisher’s exact test, were conducted using R software 2.7.3 (R Foundation, Vienna, Austria). Results indicated a significant association (p ≤ 0.05) between apical fenestration and tooth position. In the upper teeth, apical fenestrations were notably present in the mesio-buccal (17.17%) and disto-buccal (11.07%) roots of the first molars. Conversely, apical fenestrations in the lower teeth were relatively less frequent. The study revealed a negative correlation between apical fenestration and mesial inclination, rotation, and extrusion in the upper teeth. However, a positive correlation was observed between apical fenestration and lingual inclination in the upper teeth. In conclusion, this study illuminates the distribution of apical fenestration and its correlation with tooth positions, offering insights into factors influencing this defect in dental anatomy. The findings enhance our understanding of nuanced relationships between tooth position and apical fenestration in the upper and lower dental arches.
... The advent of cone beam computed tomography[CBCT] allows us to anticipate these defects in 3D images 10 . Several studies have assessed the alveolar bone defects using CBCT in cases with cleft lip and palate 11 , after rapid maxillary expansion 12,13 in adults with different skeletal patterns 6,8 and different malocclusions 14 . Hence the current study has chosen CBCT as a mode of evaluation for alveolar bone defects. ...
... Many studies have reported similar results with higher prevalence of dehiscence in buccal alveolar bone surface 6,8,[18][19][20][21][22] . This may be explained by the narrow morphology of maxilla which may result in resorption of the cortical bone covering the root surfaces 6,14,19 . According to Siriwat and Jarabak 23 , the incidence of dehiscence is positively correlated with thin alveolar bone. ...
Buccolingual position of teeth could affect the prevalence of alveolar bone defects. Presence of alveolar defects may have a deleterious effect on orthodontic treatment. The aim was to assess the prevalence and extent of dehiscence and fenestration in Class I hyperdivergent subjects and correlate it with buccolingual inclinations(BL) of maxillary first molar teeth. Methods: This retrospective study involved 80 CBCTs of class I hyperdivergent subjects divided into two groups - group A (n=33) buccolingual inclination >9º and group B (n=47) buccolingual inclination <9º. Prevalence and extent of alveolar bone dehiscence and fenestrations were measured in CBCTs using OSIRIX Lite software. Descriptive statistics, Mann Whitney U test and Spearman correlation were done for evaluating intergroup differences and correlation with Buccolingual inclination. Results: Overall prevalence of dehiscence and fenestration in maxillary first molars was 60.95% and 5% respectively. In the buccal alveolar bone, prevalence of dehiscence was highest in group A (84.6%) for 16 and in the lingual alveolar bone prevalence of dehiscence was highest in group B (71.4%) for 26 . On intergroup comparison, the extent of lingual alveolar bone dehiscence (26) in group B was significantly higher (p value <0.05) than in group A. No significant correlation between the extent of dehiscence and fenestration with buccolingual inclination of molar teeth was noted. Conclusion: Molar teeth with BL inclinations of more than 9º had higher prevalence of dehiscence on the buccal side and molar teeth with BL inclinations less than 9 degrees had more dehiscence on the lingual side. But no significant correlation of BL inclination with prevalence and extent of dehiscence and fenestration was noted.
... The mean and standard deviation values for age in the study sample were 34.8 ± (10.8) years old with a minimum of 18 and a maximum of 60 years old. The patients were categorized in to 3 groups according to age; 1st group (18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29) ...
... While for dehiscences, they were significantly more common in mandible (60.4%), which is also coinciding with all the other previous reports. However, explanation of this finding could not be discussed separately without addressing the differential frequency of dehiscence according to teeth types, as our results showed that the highest prevalence of dehiscence was found in lower central incisors which was in agreement with the studies assessing frequency of dehiscence in different skeletal patterns 8,15,24 . And not far from those who found that dehiscences were most frequently found in mandibular canines 2,3,12,14,16,17,18,19 . ...
Background: This study aimed to evaluate the frequency of root fenestration and dehiscence in a sample of adult Egyptian population using CBCT.
Materials and Methods: 100 CBCT scans showing both maxillary and mandibular dentation “with total number of 2576 teeth” were selected from the database of OMFR department, faculty of Dentistry, Cairo University, based on certain eligibility criteria. Identification of Fenestration and Dehiscence on CBCT scans was done using the identification criteria first mentioned by Davies et al 1974.
Results: Fenestration was found in 17 % of the population with a total of 26 affected teeth (representing 1% of the involved teeth) while dehiscence was found in 50% of the population with a total of 194 affected teeth (representing 7.5% of the involved teeth). Upper 2nd molars showed the highest prevalence of fenestration while lower central incisors showed the highest prevalence of dehiscence. Gender was found not significantly affecting the incidence of both defects, while age was significantly affecting the incidence of dehiscence, where older subjects were found to be 11.5 times more prone to develop dehiscence than younger subjects.
Conclusions: The relative common finding (50%) of dehiscence and to lesser extent (17%) fenestrations supports the need for CBCT examination before any surgical &/or implant treatment procedures even in areas believed previously to be safe zones “lower anterior region” to avoid complications related to the initial presence of fenestrations and dehiscence.
... Numerous studies investigated the presence of dehiscence or fenestration. 4,5,17,19,20,21,22 However, there is scarce literature about the dimensions of defects, their location at the root, the coexistence of dehiscence and fenestration and the involvement of apical foramen. 2,6 Our study not only examined the presence of a bone defect but also the dimensions or location according to two classifications. ...
... This result is in agreement with Pan et al. 2 Previous studies that used skulls stated the prevalence of fenestration in the anterior maxilla was between 0.42 and 23.03%, while the results of other studies that used CBCT were between 5.65% and 14.33% (Table 5). 2,4,5,21,22,24,25,26,27 Our study reported a higher prevalence (35.66%) compared with the literature. This difference can be related to racial factors and different methodologies of studies. ...
Background:
The primary objective of the study was to assess the buccal bone thickness (BT), evaluate and compare the prevalence of bone fenestration and dehiscence in anterior maxillary teeth using cone-beam computed tomography (CBCT).
Methods:
Images of 300 maxillary anterior teeth were investigated. The BT was measured at the bone crest, 3,6,9 mm from the bone crest, and apical. Fenestration and dehiscence were recorded according to Yang and Pan's classification. Student's t-test and one-way ANOVA were performed for statistical analysis.
Results:
Fenestration and dehiscence rates were 35.66% and 20%, respectively. Type-III fenestration was higher in group 3(>65 years) (P=0.028). Type-I and IV fenestration and CII DII dehiscence were more common in canines (P>0.05). Fenestration involving 2/3 (46.76%) and 1/3 (44.84%) of the root length was more common. Fenestrations involving the entire root was 8.4%. Most of the dehiscence (63.3%) involved 1/3 of the root length. Dehiscence involving 2/3 of the root length and the entire root were 5% and 9.95%, respectively. The coexistence of fenestration and dehiscence was 8.3%. Dehiscence on the palatal aspect was detected in 1.65% of the anterior maxilla.
Conclusions:
The rate of BT ≤1 mm was 80.08%, and ≥2 mm was 3.66%. Fenestration was most common in canines. Fenestration was mostly located in the apical third, while dehiscence was mostly located in the coronal third. © 2022 Australian Dental Association.
... Anatomically, the buccal bone wall is thinner than the lingual wall, 23 as well as it may contain bone dehiscence (i.e., "areas in which the root is denuded of bone and portions of the root surface are covered only by soft tissue, and the area extends to through the marginal alveolar bone") 21 and fenestrations (i.e., "window-like apertures or openings in the alveolar bone over the root without comprising the marginal crestal bone"). 21,[24][25][26][27] Indeed, bone dehiscence and fenestrations can be found in approximately 60% of the individuals and affecting 10% of the overall number of teeth. 24 However, in the anterior mandibular region, the presence of malocclusions may lead to a noteworthy increase in the frequency of fenestrations and dehiscence to approximately 35% and 50%, respectively. ...
... 24 However, in the anterior mandibular region, the presence of malocclusions may lead to a noteworthy increase in the frequency of fenestrations and dehiscence to approximately 35% and 50%, respectively. 26,27 Consequently, these anatomical features in combination to a buccal tooth movement (and its resulting effect of bone resorption caused by osteoclastogenesis triggered by the application of pressure forces on the bone walls) may induce the onset and progression of GRD, 5,28 as well as lead to clinical scenarios where PPM therapy (via soft tissue augmentation) shall be required to "intercept" the problem. ...
Objectives: The aim of this review is to address the potential applications of allogenous dermal matrix (ADM), as an alternative to subepithelial connective tissue graft (SCTG), in promoting periodontal phenotype modification (PPM) of challenging periodontal-orthodontic clinical scenarios.
Overview: The rationale behind the need of changing thin to thick gingival tissues is associated to the superior and more stable treatment outcomes promoted by PPM therapy. PPM, via soft tissue grafting, leads to clinical and histological changes of the pre-established original genetic conditions of the gingiva. Although SCTG-based procedures are recognized as the "gold standard" for the treatment of sites requiring root coverage and gingival augmentation, ADM has been recognized as the most suitable alternative to SCTG, particularly in clinical scenarios where the use of autogenous grafts is not possible. Thus, ADM is considered an optimal option for the treatment of patients with a history (or in need) of orthodontic tooth movement, due its two-fold potential indication: (1) the promotion of periodontal soft tissue phenotype modification; and (2) its use, as a barrier membrane, in hard tissues augmentation procedures.
Conclusions: ADM is a viable option for soft tissue augmentation, as well as for treatment approaches involving buccal bone gain.
... 7,8 The prevalence of ABDs has been reported to vary between 7%-89%, [9][10][11][12] whereas the prevalence of ABFs ranges between 5%-61%. [9][10][11] The ABDs and ABFs are common in patients with various malocclusions such as Class I, Class II, and bimaxillary protrusion, 6,9,13,14 and may lead to gingival recession and bone loss during OT. Moreover, rapid maxillary expansion 15 and fixed orthodontic appliances 16 have been associated with an increased incidence of ABDs/ABFs. ...
... A sample size of 22 subjects achieves 80% power to detect a 30% change in the number of ABDs after CAT in adults with a significance level set at a 5 0.05. 13,15 Mean 6 SD values and counts (%) were calculated for pretreatment continuous (age, ANB angle, treatment duration) and categorical variables (gender, race), respectively. Mean 6 SD values were calculated at T1 and T2 for U1-SN, FMIA, intercanine and intermolar widths, and dental treatment changes (T2 À T1). ...
Introduction: This study aimed to assess the association between nonextraction clear aligner therapy (CAT)
and the presence of alveolar bone dehiscences (ABDs) and fenestrations (ABFs) in adults with mild-tomoderate
crowding. Methods: Cone-beam computed tomography images from 29 adults were obtained before
and immediately after nonextraction CAT. Total root lengths were evaluated in axial and cross-sectional slices.
Linear measurement for dehiscence (LM-D) was defined as the distance between the alveolar crest to the
cementoenamel junction of each root (critical point set at 2 mm). Linear measurement for fenestration (LM-F)
was recorded when the defect involved only the apical one-third of a root (critical point set at 2.2 mm).
Counts of ABDs/ABFs and magnitudes of LM-Ds/LM-Fs were recorded before and immediately after
nonextraction CAT at buccal and lingual root surfaces. Binary logistic regression analyses and repeated
measures analyses of variance were performed. Results: Counts of ABDs/ABFs and magnitudes of LM-Ds/
LM-Fs increased at most jaw locations and root surfaces. Nonextraction CAT was associated with an
increased presence of ABDs and ABFs. Nonextraction CAT was associated with a higher magnitude of LMDs
but not LM-Fs. Conclusions: Immediate posttreatment cone-beam computed tomography scans showed
that nonextraction CAT is associated with increased ABDs and ABFs in adults with mild-to-moderate
crowding.
... Several studies have investigated the prevalence of RF in untreated patients with malocclusions, however further investigation is essential, as the results seem inconclusive. RF's correlation with different sagittal skeletal patterns has been examined [45,46]. Two IE-CBCT studies examining Chinese [47] and Korean [48] patients with untreated Class III malocclusions found RF to be very frequent 32% and 43% respectively, especially in the mandible. ...
... The identification of pre-existing RFs and of the thickness of the alveolar bone supporting teeth are two important considerations that affect treatment planning prior to orthodontic treatment. Care must be exercised to ensure that the direction of movement and the frequency and magnitude of orthodontic forces will not cause the development and exacerbation of RF [46], especially in maxillary expansion techniques [56]. Ideally, the treatment plan should help move teeth with defects inside the bony housing. ...
The aim of this systematic scoping review is to explore the literature on root fenestration prevalence and its possible etiologic, aggravating and predisposing clinical factors. A systematic search was conducted in 5 electronic databases, by two independent reviewers, without any language and date restrictions. Forty‐six full‐text records were included in the study, out of which 27 were used for prevalence analysis and 42 for clinical factor analysis. The results suggest that the literature is heterogenous, with major differences in the study protocols and results' presentation, providing limited information regarding root fenestration prevalence and possible racial distribution patterns. Further documentation is also required regarding clinical parameters that may affect root fenestration's presence and severity. Despite their few limitations, retrospective cone beam computed tomography studies with high‐resolution protocols, as well as open flap studies for direct observation of possible root fenestration sites, seem the most reliable methods to better comprehend its presence and possible distribution patterns.
... In addition, the inclination of the mandibular incisors is also mostly buccal so that the surrounding alveolar bone becomes thinner. 18 Fenestration and dehiscence are more commonly found on the facial (labial/buccal) surface than the lingual surface of the root and are more common in anterior teeth than posterior teeth. It was further explained that the anterior teeth most prone to dehiscence were the lower central incisors. ...
... It is associated with thinner bone on the buccal surface, where the amount of bone marrow is less dense than in the lingual area. 18,20 On the palatal surface, higher bone remodeling is believed to result from tooth retraction movements that are often performed in orthodontic treatment. Although the loss of alveolar bone on the palatal side does not affect the esthetics, it can cause loss of periodontal tissue support. ...
Considering the alveolar bone thickness (ABT) in orthodontic treatment needs special attention. The movement of teeth depends on the mechanism of bone remodeling and tissue response to orthodontic forces to evaluate ABT of the maxillary and mandibular anterior teeth in various types of malocclusion. Methods: Only prospective original articles reporting ABT in subjects who have not undergone orthodontic treatment were selected. A total of 10 studies met the eligible criteria. Most all studies measured the thickness using CBCT. ABT on the labial side of the lower anterior teeth in the class I malocclusion group was thicker than in class II. The lingual side of the apical region of the mandibular incisors was lower in the class III group than in class I or II. ABT of the maxillary teeth on the labial surface showed no significant difference among the groups, whereas the palatal side of normal occlusion had a wider bone thickness. The inclination of the upper and lower anterior teeth was influenced by differences in the skeletal malocclusion pattern, which affected the thickness of the bone. Fenestration was more common in class II malocclusion. The results showed that ABT around anterior teeth varied according to the different classifications of malocclusion. The inclination of the upper and lower anterior teeth seemed to be influenced by the sagittal discrepancies. The pattern of facial growth also affected the thickness of the bone. Accurate evaluation is very important to prevent iatrogenic risks during orthodontic treatment.
... Evangelista et al. reported that dehiscences were 35% more prevalent in patients with Class I malocclusion compared with Class II Division 1 patients before orthodontic treatment [5]. Yagci et al., in their study, reported that fenestrations had greater prevalence in the maxilla (Class I group, 18.83%; Class II group, 19.49%; Class III group, 14.06%), but more dehiscences were found in the mandible (Class I group, 24.02%; Class II group, 22.77%; Class III group, 42.64%) [6]. ...
... However, the results of the current study differed from the findings of Yagci et al., in patients with class I malocclusion before orthodontic treatment where the percentage of dehiscence and fenestrations in the lower jaw were 24.02% and 1.73%, respectively [6]. The difference may be attributed to the use of a relatively large voxel size of 0.3 in the later study by Yagci et al. [14]. ...
Background
No study has evaluated the diagnostic accuracy of cone-beam computed tomography (CBCT) imaging in detecting bone defects in orthodontic patients with Class I malocclusions. This study aimed to evaluate the accuracy of CBCT in detecting dehiscences and fenestrations before orthodontic treatment compared to the gold standard i.e., the actual clinical detection of bone defects on surgical exposure.
Methods
A validation study was undertaken at the Department of Orthodontics, University of Damascus between 29 August 2018 and 1 November 2020. The sample included 16 patients who had Class I malocclusion with moderate crowding on the lower anterior teeth.
Results
The proportion of dehiscence diagnosed on CBCT images was approximately two-and-a-half times greater than that found on direct examination i.e., 42.7% versus 17.7%, respectively. The proportion of fenestrations was almost three times greater when diagnosed on CBCT images compared to the gold standard i.e., 39.5% versus 13.5%, respectively. The sensitivity of CBCT imaging in detecting dehiscence and fenestration was 100%. The specificity of CBCT imaging ranged from 45.5% to 86.7% and from 50% to 86.7% for dehiscence and fenestration detection, respectively. Also, the diagnostic accuracy of CBCT imaging ranged from 44% to 87.5% and from 56% to 87.5% for dehiscence and fenestration detection, respectively.
Conclusions
The proportion of dehiscence diagnosed on CBCT images was approximately two-and-a-half times greater than that found on direct examination, and the proportion of fenestrations was almost three times greater when diagnosed on CBCT images compared to the gold standard. The CBCT overestimates the dimensions of the linear measurements compared to those measured by the gold standard.
... Uysal ve ark. 22 Sınıf I, II ve III malok-lüzyona sahip bireylerdeki diş eti çekilmesi ve fenestrasyon görülme sıklığını konik ışınlı bilgisayarlı tomografi ile değerlendirdikleri çalışmada, Sınıf III malok-lüzyona sahip hastalarda diş eti çekilmesi görülme oranını % 9,57, fenestrasyon görülme oranını ise % 2,71 olarak hesaplamışlardır. Sınıf III maloklüzyonda diğer anomali gruplarına göre diş eti çekilmesi prevalansının en yüksek, fenestrasyon prevalansının ise en düşük olduğu görülmüştür. ...
CAMOUFLAGE TREATMENT OF CLASS III MALOCCLUSION PATIENTS
... These bone lesions are commonly present in malocclusions, mainly in the anterior region of class III malocclusion, affecting orthodontic treatment, which must use the morphology of the alveolar bone lamina to define the procedures to be performed, since dehiscence and fenestration, during orthodontic treatment, can lead to gingival recession and alveolar bone loss [6]. For safe tooth movement in cases of dehiscence and fenestration, due to the thin thickness of the alveolar bone plates, it is important to consider grafting, ...
Introduction: Fenestration and dehiscence are alveolar bone defects. Although not considered a pathology, these alveolar bone defects end up influencing dental treatment, such as surgeries, mainly periodontal, and therefore must be considered during treatment planning. However, currently, little is known about the biomechanical origin of these bone formations. The aim of the study was to use the finite element method (FEM) to test hypotheses of predictive factors for fenestrations and dehiscence in human alveolar bone.
Methods: A FEM simulation of the action of functional, parafunctional, and orthodontic occlusal loads on the upper central incisor and upper canine was performed. For the simulation, a three-dimensional model of an adult human skull, fully dented and with intact bone structure, was constructed from computed tomography images. The buccal alveolar bone lamina was evaluated considering the calculation of equivalent stresses, as well as maximum principal stresses.
Results: The action of functional and parafunctional forces on the incisal edges and the orthodontic force on the buccal face of the upper central incisor and upper canine teeth generated tensions at different levels of magnitude in the buccal bone lamina, varying in regions, at all levels of strength. Changing levels of force magnitude resulted in variations in relation to the level of deformation.
Conclusion: The computational simulation using the FEM was able to identify a difference in stress in the alveolar bone tissue in each of the applied forces. The difference in stresses obtained may suggest the formation of dehiscence or fenestration in the region studied.
... On the other hand, it was demonstrated that, under some circumstances, an increase in labial alveolar bone due to orthodontic mandibular incisor retraction can be expected [8]. A previous study indicated that Class II patients had a greater prevalence of fenestration than Class I and Class III malocclusions [9]. Moreover, skeletal Class II patients have thinner labial cortical bone in mandibular anterior teeth than skeletal Class I patients [10], which demonstrates periodontal risks in the presurgical decompensation phase of mandibular incisors. ...
Background
The aim of the present study was to compare periodontal support changes during retraction of mandibular anterior teeth for skeletal Class II malocclusion with different facial divergence and to analyze relevant factors influencing bone remodeling by applying three-dimensional (3D) cone-beam computed tomography (CBCT) reconstruction technology.
Methods
Forty-eight patients with Class II malocclusion requiring surgical orthodontic treatment enrolled in the study were divided into the hyperdivergent group ( n = 16), normodivergent group ( n = 16) and hypodivergent group ( n = 16) according to their vertical skeletal patterns. Cone-beam computed tomography (CBCT) scans were obtained before treatment (T1) and after presurgical orthodontic treatment (T2). The two-dimensional (2D) alveolar bone morphology, movement of mandibular central incisors and volume of the alveolar bone around incisors were measured on the labial and lingual sides by 3D CBCT reconstruction technology. Statistical analyses were performed with one-way ANOVA, paired t tests and multiple linear regression.
Results
During presurgical orthodontic treatment, the alveolar bone height on the labial side of the hyperdivergent group decreased significantly ( P ≤ 0.05), but was maintained in the normodivergent and hypodivergent groups ( P > 0.05). However, the alveolar bone volume, alveolar bone thickness at each level and alveolar bone height on the lingual side decreased significantly for all the groups. Apart from the initial morphometric measurements at T1, the morphology of lingual alveolar bone at T2 was significantly influenced by the direction and amount of tooth movement. Horizontal retraction and vertical protrusion of the root apex were negatively related to the alveolar bone on the lingual side after presurgical orthodontic treatment.
Conclusion
For Class II malocclusion patients undergoing presurgical orthodontic treatment, the changes in the periodontal support of the lower central incisors varied in different vertical skeletal patterns. There exists a great periodontal risk of alveolar bone resorption on the lingual side for various vertical types. To avoid alveolar bone deterioration, it is essential to investigate the bone remodeling of patients with different alveolar bone conditions and cautiously plan tooth movement prior to orthodontic treatment. Moreover, 3D measurements based on CBCT construction can provide complementary information to traditional 2D measurements.
... 58−62 Regarding these bone features, the presence of fenestrations and dehiscence have been detected in most individuals (i.e., 60 %) and in up to 50 % of mandibular anterior teeth. 59 Taking into consideration only patients displaying Class I, II or III malocclusion the proportion of teeth presenting fenestrations and dehiscence may also be considered high, as demon- 62 Recent American Academy of Periodontology's Best Evidence systematic review on the use of CBTC for risk assessment of the dentoalveolar bone changes influenced by tooth movement, 3-dimensional imaging analysis may be used to improve the decision-making process and help to prevent the development of GRD. In particular in patients with thin periodontal phenotype, who are at increased risk for developing additional periodontal tissue loss, 3D imaging may be most useful. ...
Objective: this review aims to explore key aspects related to the treatment of gingival recession defects (GRD) and sites lacking keratinized gingiva in orthodontic patients. It focuses on five crucial core aspects: 1) risk assessment for GRD development; 2) diagnosis, characteristics, and the dilemma surrounding GRD treatment necessity; 3) the evolution of root coverage procedures and the significance of modifying soft tissue phenotype for gingival margin stability; 4) the development and progression of gingival recessions in orthodontic patients; and 5) the staging of orthodontic and periodontal therapies; specifically, the consideration of preemptive soft tissue phenotype modification (STPM) or treatment of GRD. Overview and Conclusions: the management of GRD and sites lacking gingiva or with a thin mucosal phenotype, as well as the staging of periodontal and orthodontic treatment, should be guided by the positioning of the tooth within the alveolar bone envelope and the periodontal phenotype. In cases where the gingival phenotype is thin (< 1 mm), with or without GRD, it is advisable to perform preemptive soft tissue augmentation (PMT) prior to orthodontic treatment if the tooth is located within the alveolar bone envelope. Conversely, if the tooth is positioned outside the alveolar bone housing, orthodontic tooth movement should be employed to reposition the tooth within the bone housing before any soft tissue augmentation procedure is performed. Research has demonstrated a negative correlation between tooth position and periodontal root coverage, whereas tooth repositioning has shown a two-fold positive effect: 1) improving the surrounding soft tissues by reducing or eliminating the defect, and 2) enhancing the implementation and wound healing dynamics of root coverage procedures.
... Orthodontically induced dehiscence and fenestration, as well as root resorption happen more frequently in the anterior region, as retraction of protrusive anterior teeth is a common scenario which requires the extraction of first premolars and a long duration of active orthodontic forces [17][18][19][20][21]. Therefore, an orthodontic force detection bracket and FEM were applied to measure the retraction force on the upper incisor and simulate the moving tendency. ...
This study aimed to develop an ultraminiature pressure sensor array to measure the force exerted on teeth. Orthodontic force plays an important role in effective, rapid, and safe tooth movement. However, owing to the lack of an adequate tool to measure the orthodontic force in vivo, it remains challenging to determine the best orthodontic loading in clinical and basic research. In this study, a three-dimensional (3D) orthodontic force detection system based on piezoresistive absolute pressure sensors was designed. The 3D force sensing array was constructed using five pressure sensors on a single chip. The size of the sensor array was only 4.1 × 2.6 mm, which can be placed within the bracket base area. Based on the barometric calibration, conversion formulas for the output voltage and pressure of the five channels were constructed. Subsequently, a 3D linear mechanical simulation model of the voltage and stress distribution was established using 312 tests of the applied force in 13 operating modes. Finally, the output voltage was first converted to pressure and then to the resultant force. The 3D force-detection chip was then tested to verify the accuracy of force measurement on the teeth. Based on the test results, the average output force error was only 0.0025 N (0.7169%) (p = 0.958), and the average spatial positioning error was only 0.058 mm (p = 0.872) on the X-axis and 0.050 mm (p = 0.837) on the Y-axis. The simulation results were highly consistent with the actual force applied (intraclass correlation efficient (ICC): 0.997–1.000; p < 0.001). Furthermore, through in vivo measurements and a finite element analysis, the movement trends generated when the measured orthodontic forces that acted on the teeth were simulated. The results revealed that the device can accurately measure the orthodontic force, representing the first clinical test of an orthodontic-force monitoring system. Our study provides a hardware basis for clinical research on efficient, safe, and optimal orthodontic forces, and has considerable potential for application in monitoring the biomechanics of tooth movement.
... Camouflaging severe skeletal discrepancies in which teeth are repositioned at their anatomic limits may enhance the occurrence and severity of iatrogenic sequelae. [13][14][15] This is concerning when incisor protrusion is planned in the presence of thin labial bone, gingival phenotype, and thickness. 1,3,13,[16][17][18][19] A significant association between thin GP with skeletal Classes I and III for the left MCI (P ¼ .0183) ...
Objectives:
To investigate the association between the width of keratinized gingiva (WKG), gingival phenotype (GP), and gingival thickness (GT) with craniofacial morphology in sagittal and vertical dimensions.
Materials and methods:
WKG, GP, and GT of mandibular anterior teeth in 177 preorthodontic patients (mean age 18.38 ± 5.16 years) were assessed clinically using a periodontal probe, a Colorvue Biotype Probe, and ultrasound by a single examiner. Patients were grouped into skeletal Class I, II, and III and hyperdivergent, normodivergent, and hypodivergent based on ANB and SN-MP angles. Mandibular incisor inclination (L1-NB) was also measured. Clinical and cephalometric measurements were repeated to assess inter- and intraexaminer reproducibility.
Results:
A significant association was found between thin GP and skeletal Classes I and III for the left mandibular central incisor (MCI; P = .0183). In skeletal Class III patients, L1-NB angle demonstrated a decreasing trend as phenotype thickness decreased. A significant association was found between thin phenotype and normodivergent and hypodivergent groups for MCIs (left: P = .0009, right: P = .00253). No significant association between WKG or GT and craniofacial morphology was found.
Conclusions:
Thin GP is associated with skeletal Class I and III for the left MCI. Thin GP is associated with hypodivergent and normodivergent skeletal patterns for the MCIs. There was no association between WKG and GT and craniofacial morphology in both skeletal and vertical dimensions. Dental compensations that exist due to different craniofacial morphology may influence the GP.
... This suggests that soft tissue plays a more important role in the pathogenesis of OGE than bone tissue. Moreover, the thicker the periodontal tissue, the less likely there are to be clinical changes in the alveolar bone (Persson et al., 1998;Yagci et al., 2012). Thus, orthodontists should pay more attention to patients with a thin gingival biotype and a thin bone biotype (Evangelista et al., 2010). ...
Introduction: Open gingival embrasure (OGE) is a common complication in adults following clear aligner therapy and the influence of gingival or alveolar bone biotype on OGE is of great concern. Unfortunately, due to the limited number of patients with clearaligner therapy and the clinical methods to distinguish the gingival biotype of patients being invasive, it is difficult to carry out clinical studies on the gingival or alveolar bone biotype of the OGE. In the meanwhile, the detailed biomechanics of the occurrence of OGE remains unknown. The goal of this study was to establish a new model to simulate the virtual space region, namely, the OGE region, to investigate the relationship between alveolar bone biotype and the occurrence of OGE, and explore potential biomechanical factors related to OGE.
Methods: The OGE region in the interproximal space was established using a filler with a very low modulus of elasticity (1 × 10⁻⁶ MPa). To illustrate the biomechanics of OGE more exhaustively, a line was created at the top of the alveolar crest along the proximal tooth root. FEA was then used to analyze the biomechanics of the surrounding tissues, the OGE region and the line at the top of the alveolar crest along the proximal tooth root of the central incisor under two different labial bone thicknesses (thick and thin) with an axial inclination of 80°, 90° and 100°.
Results: During intrusion of the incisors in clear aligner therapy, as inclination increased or bone tissue became thinner, the stress in the surrounding tissues [tooth root, alveolar crest, and periodontal ligament (PDL)] was greater. In the OGE region and interproximal alveolar crest, the strain increased with increasing inclination and labial bone thinning. The results from the line at the top of the alveolar crest along the proximal tooth root showed more detailed biomechanics: In all groups, stress and strain were focused on the mesial-labial alveolar crest. Interestingly, our results also demonstrated that when OGE occurs, other complications may arise, including root resorption and bone dehiscence.
... Most patients with malocclusion have skeletal discrepancies, and the linked compensations of alveolar bone morphology and tooth angles increase the difficulty of diagnosis [9]. Moreover, different sagittal skeletal patterns are associated with different degrees of risk of dehiscence and fenestration [10]. Recent studies have therefore focused on the effect of different skeletal facial morphologies on the thickness of the alveolar bone in the anterior region or on the position of the anterior teeth in the alveolar bone [11][12][13]. ...
Background
No studies have focused on cortical anchorage resistance in cuspids, this study aimed to characterize the cortical anchorage according to sagittal skeletal classes using cone-beam computed tomography (CBCT).
Methods
CBCT images of 104 men and 104 women were divided into skeletal class I, II, and III malocclusion groups. Skeletal and dental evaluations were performed on the sagittal and axial cross-sections. One-way analysis of variance followed by least significant difference post-hoc tests was used for group differences. Multiple linear regression was performed to evaluate the relationship between influential factors and cuspid cortical anchorage.
Results
All cuspids were close to the labial bone cortex in different sagittal skeletal patterns and had different inclinations. There was a significant difference in the apical root position of cuspids in the alveolar bone; however, no significant difference in the middle or cervical portions of the root was found between different sagittal facial patterns. The middle of the cuspid root was embedded to the greatest extent in the labial bone cortex, with no significant difference between the sagittal patterns. For all sagittal patterns, 6.03 ± 4.41° (men) and 6.08 ± 4.45° (women) may be appropriate root control angles to keep maxillary cuspids’ roots detached from the labial bone cortex.
Conclusions
Comparison of skeletal class I, II, and III malocclusion patients showed that dental compensation alleviated sagittal skeletal discrepancies in the cuspid positions of all patients, regardless of the malocclusion class. Detailed treatment procedures and clear treatment boundaries of cuspids with different skeletal patterns can improve the treatment time, periodontal bone remodeling, and post-treatment long-term stability. Future studies on cuspids with different dentofacial patterns and considering cuspid morphology and periodontal condition may provide more evidence for clinical treatment.
... Studies have found that the incidence of fenestration in the anterior teeth of Class II patients was higher than that of Class I and Class III patients. In Class II patients, 11.88% had bone fenestration, and 18.51% had bone dehiscence [16]. In the present study, 98.3% of maxillary central incisors and 93.2% of maxillary lateral incisors had Type I sagittal root positions in the Class II division 2 group, suggesting that such groups have an insufficient labial alveolar bone. ...
Background:
Safe orthodontic tooth movement should be performed within the alveolar bone. The purpose of this study was to evaluate the morphology of the alveolar bone of incisors.
Materials and methods:
This retrospective study included pretreatment cone beam computed tomography of 120 patients with malocclusion. Patients were divided into 4 groups (Class I, Class II division 1, Class II division 2 and Class III) according to the subspinale-nasion-supramental (ANB) angle and occlusal relationship. The sagittal root positions, anterior and posterior root-cortical bone angles (AR-CA and PR-CA), root-crown ratios (RCR) and alveolar bone thickness were evaluated.
Results:
The sagittal root positions were mainly positioned against the labial cortical plate in the maxillary incisors of the Class II division 2 group and engaged by both the labial and palatal cortical plates in the mandibular incisors of the Class III group. The AR-CA was lower than that in the other groups (P < 0.01) in the maxillary incisors of the Class II division 2 group, and the AR-CA and PR-CA were lower than those in the other groups (P < 0.01) in the mandibular incisors of the Class III group. The alveolar thickness showed no significant difference between the Class II division 1 group and the Class I group (P > 0.05), the middle and lower anterior alveolar thickness (LAAT and MAAT) were lower than those in other groups (P < 0.01) in the maxillary incisors of the Class II division 2 group, and the alveolar thickness at the measurement sites of the middle and lower line were lower than those in other groups (P < 0.01) in the mandibular incisors of the Class III group. The RCR had a moderate positive correlation with the LAAT.
Conclusion:
Based on several limitations, this study found that maxillary incisor roots were at risk of penetrating the alveolar bone of Class II division 2 patients, and mandibular incisors may have a relatively small range of safe movement on both the labial and lingual sides of Class III patients during orthodontic treatment.
... Sameshima and Sinclair (18) found that root resorption was twice as likely to occur in maxillary central incisors than in mandibular central incisors. Ahmet (19) reported that the contact of the maxillary central incisor roots with hard tissue structures, such as incisive canals and cortical bone, was a significant risk factor for root resorption. In addition, Baba et al. (20) Therefore, if the tooth movement pattern can be predicted by lateral cephalograms taken before the start of active treatment and the structure of the maxillary central incisor root and its positional relationship with the surrounding bone can be determined by CT, the risk of root resorption can be assessed. ...
This study aimed to evaluate the effect of CT values of the tooth root and bone on root resorption using data obtained before and after orthodontic treatment. Forty-one patients with jaw deformities were divided into those with and without root resorption （n = 18 and 23, respectively）. The distance from the anatomical root apex to the edge of the incisive canal was measured using axial CT sections before active treatment. The distance from the anatomical root apex to the labial and palatal cortical bone and the CT values of the root and alveolar bone were measured and compared using sagittal CT sections. The tooth axis and vertical and lateral movements of the maxillary right central incisor were examined using lateral cephalograms before and after treatment. Root resorption group showed significantly higher CT values of alveolar bone than the control group and different axial movement of the root apex and distance between the labial cortical bone and root apex on lateral cephalograms. The risk of root resorption increased with an increase in the CT values of the alveolar bone surrounding the maxillary central incisor. The horizontal movement of the root apex was associated with the distance between the labial cortical bone and root apex, and root resorption during maxillary central incisor movement.
... The prevalence of naturally occurring alveolar bone dehiscence and fenestration is high in different kinds of malocclusions [1][2][3][4][5]. These alveolar bone defects may pose potential risks for orthodontic treatment, such as gingival recession and additional bone loss [6][7][8]. ...
Silk fibroin is regarded as a promising biomaterial in various areas, including bone tissue regeneration. Herein, Laponite® (LAP), which can promote osteogenic differentiation, was introduced into regenerated silk fibroin (RSF) to prepare an RSF/LAP hybrid hydrogel. This thixotropic hydrogel is injectable during the operation process, which is favorable for repairing bone defects. Our previous work demonstrated that the RSF/LAP hydrogel greatly promoted the osteogenic differentiation of osteoblasts in vitro. In the present study, the RSF/LAP hydrogel was found to have excellent biocompatibility and significantly improved new bone formation in a standard rat calvarial defect model in vivo. Additionally, the underlying biological mechanism of the RSF/LAP hydrogel in promoting osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) was extensively explored. The results indicate that the RSF/LAP hydrogels provide suitable conditions for the adhesion and proliferation of BMSCs, showing good biocompatibility in vitro. With the increase in LAP content, the alkaline phosphatase (ALP) activity and mRNA and protein expression of the osteogenic markers of BMSCs improved significantly. Protein kinase B (AKT) pathway activation was found to be responsible for the inherent osteogenic properties of the RSF/LAP hybrid hydrogel. Therefore, the results shown in this study firmly suggest such an injectable RSF/LAP hydrogel with good biocompatibility (both in vitro and in vivo) would have good application prospects in the field of bone regeneration.
... This explained why the incidence of dehiscence at T0 in this study was lower than that in previous studies. 11,22,42,45 In our previous study, 19 we measured alveolar bone dehiscence with the naked eye during AC surgery and found that the incidence of anterior dehiscence in patients with class III malocclusion was 24.10%, consistent with this study. Therefore, we did not add ROC analysis for dehiscence. ...
Background/purpose
Alveolar bone fenestration and dehiscence is common in untreated patients and potentially harmful. This study was to evaluate the effect of augmented corticotomy (AC) on the prevention and treatment of alveolar bone defects in skeletal class III high-angle patients during presurgical orthodontic treatment (POT).
Materials and methods
Fifty patients with skeletal Class III high-angle malocclusion were enrolled, of whom 25 patients (G1) underwent traditional POT and 25 patients (G2) received AC during POT. The alveolar bone fenestration and dehiscence around the upper and lower anterior teeth were measured by CBCT. The incidence and transition of fenestration and dehiscence in the two groups were compared by the chisquare and Mann‒Whitney rank-sum tests.
Results
Before treatment (T0), the incidence of fenestration and dehiscence around the anterior teeth of all patients was 39.24% and 24.10%, respectively. After POT (T1), the incidence of fenestration in G1 and G2 was 49.83% and 25.86%, respectively, and the incidence of dehiscence in G1 and G2 was 58.08% and 32.07%, respectively. For teeth without fenestration and dehiscence at T0, more anterior teeth in G1 exhibited fenestration and dehiscence at T1 than in G2. For teeth with fenestration and dehiscence at T0, most transitions in G1 were maintained or worsened, but “cure” cases were observed in G2. After POT, the cure rates of fenestration and dehiscence in G2 were 80.95% and 91.07%, respectively.
Conclusion
During the POT of skeletal Class III high-angle patients, augmented corticotomy can significantly treat and prevent alveolar bone fenestration and dehiscence around anterior teeth.
... Therefore, tooth movement must be performed cautiously. Furthermore, alveolar bone defects in this area are a common finding before orthodontic treatment, especially on labial surfaces [14,15]. ...
Background:
The objective of the study was to ascertain whether the alveolar bone and root of the mandibular central incisor measured from cephalograms can represent the same measurements of both mandibular central and lateral incisors from CBCT.
Methods:
A total of 38 sets of CBCT images and cephalograms before treatment were selected for this study. Thicknesses included alveolar bone, cortical bone, and cancellous bone at the labial and lingual sides. Root diameter and total root-bone thickness were also evaluated. The measurements were performed at 3, 6, and 9 mm from the cemento-enamel junction. Heights included labial bone height and lingual bone height. All measurements were performed on cephalograms and CBCT images of the mandibular central incisor (L1CT) and mandibular lateral incisor (L2CT). The data were statistically analyzed using one-way ANOVA and Bonferroni tests (p < 0.01) to compare the cephalograms, L1CT, and L2CT.
Results:
The cephalograms presented thicker alveolar bone and cortical bone (labial: 0.16-0.31 mm, lingual: 0.14-0.29 mm; p < 0.001) as well as higher alveolar crest (labial: 0.46-0.48 mm, lingual: 0.38-0.39 mm; p < 0.001) than the CBCT images on both the labial and lingual sides, whereas lingual cancellous thicknesses were not significantly different (p = 0.257). The cephalograms presented greater total root-bone thicknesses than L1CT (0.19-0.30 mm; p < 0.001), whereas the cephalograms traced thinner roots than L1CT (0.18-0.23 mm; p < 0.001) and L2CT (0.39-0.59 mm; p < 0.001).
Conclusion:
Lateral cephalograms cannot represent both mandibular central and lateral incisor dentoalveolar thicknesses, heights, and root diameters the same as CBCT. However, the differences were less than 0.5 mm.
... A previous study noted that Class II and Class III subjects showed a high prevalence of bone defects surrounding the anterior mandibular teeth, with rates of up to 41.11% and 45.02%, respectively [18]. These defects usually lead to root exposure, gingival recession and even treatment relapse or failure, which pose challenges in orthodontic treatment [19,20]. Therefore, shortening the duration of orthodontic treatment and decreasing severe sequelae are of great significance for orthodontic patients, especially adults with bone fenestration and dehiscence, which are also aesthetically significant issues that are time consuming to treat. ...
Abstract Purpose The objective of the study was to explore the effect of periodontally accelerated osteogenic orthodontics (PAOO) in orthodontic patients with bone dehiscence and fenestration in the anterior alveolar region of the mandible. Methods A retrospective study was performed in 42 patients with bone dehiscence and fenestrations in the anterior alveolar region of the mandible who underwent the PAOO technique. The bleeding index (BI), probing depth (PD), keratinized gingiva width (KGW), gingival recession level (GRL), and gingival phenotype were recorded and assessed at baseline and 6 and 12 months postoperatively. Cone-beam computerized tomography was used to measure bone volume in terms of root length (RL), horizontal bone thickness at different levels, and vertical bone height at baseline and 6 months and 12 months after surgery. Results The sample was composed of 42 patients (22 males and 20 females; mean age, aged 25.6 ± 4.8 years) with 81 teeth showing dehiscence/fenestrations and 36 sites presenting gingival recessions. There was no significant difference in BI, PD, or KGW (between baseline and 6 or 12 months postoperatively) based on the clinical evaluations (P > 0.05). Gingival recession sites demonstrated a significant reduction in the GRL after surgery (P
... In the periosteum-fixed technique, the periosteum served as an encapsulating membrane to maintain bone substitutes in the desired position without displacement. As dehiscences were seen frequently in the mandibular anterior regions, vertical alveolar regeneration represents an essential outcome when treating alveolar defect underwent orthodontics [2,27]. This novel PAOO technique permits to gain extensive bone augmentation, especially for vertical augmentation by complete periosteum coverage in a dumpling-like fashion. ...
Background
Periodontal accelerated osteogenic orthodontics (PAOO) is a widely-used clinical procedure that combines selective alveolar corticotomy, particulate bone grafting, and the application of orthodontic forces. Different modifications of PAOO such as collagen-membrane coverage can better benefit patients from preventing displacement of grafts. Due to its stability, collagen-membrane coverage gradually gained popularity and became a widely-used procedure in traditional PAOO technique.
Objectives
To quantitatively investigate the radiographic changes of alveolar bone, periodontal soft tissue changes of the mandibular anterior teeth and postoperative complications in periosteum-covered techniques compared with traditional surgical technique in PAOO.
Methods
Orthodontic camouflage for dental Class II or decompensation for skeletal Class III malocclusions were included; Patients with bone defects on the buccal aspects of the anterior mandible regions confirmed by clinical and radiographic examination were randomly divided into the periosteum coverage group or traditional technique group for PAOO. Cone-beam computerized tomography (CBCT) scans were obtained before treatment (T0) and 1 week (T1) and 12 months (T2) after operation. The primary outcome variable was the vertical alveolar bone level (VBL), the secondary evaluation parameters included labial horizontal bone thickness at the midpoint of the middle third (MHBT) or apical third (AHBT) to the limit of the labial cortical surface during a 12-month follow-up. Postoperative sequelae were evaluated after 2 days and 7 days in both the groups. Periodontal parameters were analyzed at T0 and T2.
Results
Thirty-six adult subjects were eligible and recruited in the present study. Although experimental group exhibited more severe infection, no significant differences of the postoperative symptoms or periodontal parameters was found between the 2 groups ( P > 0.05). All patients were examined respectively using CBCT at baseline (T0), postoperative 1 week (T1) and 12 months (T2). Both alveolar bone height and width increased from T0 to T1 ( P < 0.001) and then reduced from T1 to T2 ( P < 0.001) in both groups. However, significant bone augmentation was achieved in each group from T0 to T2 ( P < 0.001). Furthermore, the vertical alveolar bone augmentation in the experimental group increased significantly than that in the traditional surgery ( P < 0.05).
Conclusions
Compared with traditional PAOO surgery, the periosteum-covered technique provides superior graft stabilization and satisfactory vertical bone augmentation in the labial mandibular anterior area.
... Thus, when a dehiscence occurs, the distance between the CEJ and the alveolar crest is increased. Many authors consider that a dehiscence is present, when this distance is > 2.0 mm [9,19,20]. In the present study, a proxy for dehiscence was necessary, because the CEJ is not detectable on CBCT scans. ...
Objectives
This study aims to assess whether different voxel sizes in cone-beam computed tomography (CBCT) affected surface area measurements of dehiscences and fenestrations in the mandibular anterior buccal region.
Materials and methods
Nineteen dry human mandibles were scanned with a surface scanner (SS). Wax was attached to the mandibles as a soft tissue equivalent. Three-dimensional digital models were generated with a CBCT unit, with voxel sizes of 0.200 mm (VS200), 0.400 mm (VS400), and 0.600 mm (VS600). The buccal surface areas of the six anterior teeth were measured (in mm2) to evaluate areas of dehiscences and fenestrations. Differences between the CBCT and surface scanner (SS) measurements were determined in a linear mixed model analysis.
Results
The mean surface area per tooth was 88.3 ± 24.0 mm2, with the SS, and 94.6 ± 26.5 (VS200), 95.1 ± 27.3 (VS400), and 96.0 ± 26.5 (VS600), with CBCT scans. Larger surface areas resulted in larger differences between CBCT and SS measurements (− 0.1 β, SE = 0.02, p < 0.001). Deviations from SS measurements were larger with VS600, compared to VS200 (1.3 β, SE = 0.05, P = 0.009). Fenestrations were undetectable with CBCT.
Conclusions
CBCT imaging magnified the surface area of dehiscences in the anterior buccal region of the mandible by 7 to
9%. The larger the voxel size, the larger the deviation from SS measurements. Fenestrations were not detectable with CBCT.
Clinical relevance
CBCT is an acceptable tool for measuring dehiscences but not fenestrations. However, CBCT overestimates the size of dehiscences, and the degree of overestimation depends on the actual dehiscence size and CBCT voxel size employed.
Keywords Cone-beam computed tomography · Dehiscence · Fenestration · Accuracy · Reliability
... Firstly, marginal bone loss and gingival recession are the potential periodontal risks when large-scale retraction is performed in adults [3]. In particular, patients with bialveolar protrusion demonstrate thin and elongated upper and lower anterior alveoli [4], and dehiscence and fenestration are commonly seen in their naturally occurring alveolar bone, especially in the lower anterior region [5]. Besides, the tissue response of adults to orthodontic forces including cellular activity and conversion of collagen fibers is less reactive compared to adolescent patients [2], resulting in worse periodontal remodeling. ...
Background
The patients of bialveolar protrusion always demonstrate thin anterior alveoli which may aggravate subsequent gingival recession and bone loss during retraction. This study aimed to investigate the periodontal changes, including alveolar height, thickness, and area, and the width of keratinized gingiva, in mandibular anterior teeth after augmented corticotomy-assisted orthodontics (ACAO) compared with traditional orthodontics.
Methods
Twenty adult patients with skeletal class I bialveolar protrusion were selected from two groups: ACAO group (augmented corticotomy on the labial side of the anterior mandibular teeth, n = 10) and control group (conventional orthodontics, n = 10). In all patients, four first premolars were extracted and the incisors were retracted under the maximum anchorage. The measurements included the labial alveolar bone area, vertical alveolar bone height, alveolar bone thickness surrounding the mandibular anterior teeth, root length, gingival recession and width of keratinized gingiva after alignment (T0) and 3 months after space closure (T1).
Results
The labial alveolar height, area, and thicknesses all decreased after space closure in the control group but significantly increased in the ACAO group. The decrease in the lingual alveolar height was statistically less in the ACAO group than that in the control group. Besides, the width of keratinized gingiva increased in the ACAO group but decreased in the control group. There was no significant difference in the changes of root length between groups. The dentoalveolar changes between anterior teeth were consistent but with different scales. The lateral incisors gained the most labial bone height and area.
Conclusion
Compared to conventional orthodontics, ACAO provided a more favorable effect of improving periodontal status surrounding the mandibular anterior teeth for Class I maxillary protrusion patients.
Introduction
The purpose of this study was to investigate the efficiency of segmental Le Fort I osteotomy in clear aligner therapy of skeletal Class III deformities and to explore whether Le Fort I segmental osteotomy was effective for maxillary incisor axis correction and reduced the duration of perioperative orthodontics.
Materials and Methods
Patients who had skeletal Class III deformities (ANB<0) treated with extraction of the maxillary first premolars, segmental Le Fort I osteotomy, and clear aligners therapy were included in this retrospective study. We measured the amount of tooth extraction space that was closed by surgery and recorded the preoperative orthodontic and total treatment duration. Lateral cephalograms were analyzed to measure changes of maxillary incisor inclination before treatment (T0), 1 week before surgery (T1), 1 week after surgery (T2), and after total orthodontic treatment (T3). Statistical analyses were performed, and the P value was set at 0.05.
Results
The sample was composed of 15 patients aged 19 to 30 (M=22.9) years. The average preoperative orthodontic treatment duration was 16.2±5.22 mo, with 33.5 pairs of clear aligners. The gap at the extraction site decreased from 5.42±1.57 mm to 0.80±0.62 mm on average after surgery. U1-SN and U1-NA(deg) increased sparingly with preoperative decompensation, decreased in quantity after surgery, and then slightly increased with postoperative compensation (T2<T3<T0<T1; △ U1-SN, △ U1-NA: T1-T2, P <0.05; T0 - T1 and T2-T3, P >0.05).
Conclusions
Le Fort I segmental osteotomy assisted decompensation of the upper anterior teeth and reduced the duration of preoperative orthodontics with clear aligners.
Objectives
To measure the alveolar bone thickness and root apex position in the upper anterior teeth of adults with Class Ⅱ malocclusion, and to explore the correlation with the corresponding cephalometric skeletal indexes.
Materials and Methods
Retrospective data collection was done on 90 adult patients with Class Ⅱ malocclusion. Measurement of sagittal skeletal patterns (SNA, SNB, ANB), vertical skeletal patterns (GoGn-SN), labial, lingual and total alveolar bone thickness in the root apex area (Tlabial, Tlingual, Ttotal), the labial, lingual and total rotation range of root (Rlabial, Rlingual, Rtotal), calculating root apex position (Pdistance, Pangle), and conducting correlation research.
Results
Tlabial(1.08 ± 0.96mm) and Rlabial (8.65 ± 7.33°) were significantly smaller then Tlingual(5.07 ± 1.7mm) and Rlingual(35.68 ± 14.82°) (P < 0.01) respectively; Ttotal was 6.15 ± 2.06mm, and Rtotal was 44.33 ± 14.38°; The maxillary central incisor root apex was situated at about 20% of the labial side of the alveolar bone (Pdistance: 19.04 ± 14.58%, Pangle: 21.10 ± 15.64%). Pearson correlation showed that: Ttotal, Rlingual and Rtotal were negatively correlated with GoGn-SN (r=-0.415, P < 0.01; r=-0.358, P < 0.05; r=-0.444, -0.411, P < 0.01); Ttotal, Rlingual and Rtotal were positively correlated with SNB (r = 0.316, P < 0.05; r = 0.421, P < 0.01; r = 0.476, P < 0.01).
Conclusions
In Class Ⅱ malocclusion the root apex is located on the labial side of the alveolar bone, and the thickness of the alveolar bone on the labial side is thin. The labial side of the maxillary incisor and the total alveolar bone thickness should be carefully examined in patients with high mandibular plane angle and mandibular retraction.
Clinical Relevance
The study shows that it is important to evaluate the alveolar bone thickness and root apex position before orthodontic treatment, and to guide clinical practice from cephalometric measurement.
Objective
To compare the prevalence of fenestration and dehiscence between pre‐ and post‐orthodontic treatment and to explore the factors related to fenestration and dehiscence in the anterior teeth after treatment.
Methods
This study included 1000 cone‐beam computed tomography (CBCT) scans of 500 patients before (T1) and after (T2) orthodontic treatment. These images were imported into Dolphin 11.9 software to detect alveolar fenestration and dehiscence in the anterior teeth area. The chi‐square test and Fisher's exact test were performed to compare the prevalence of alveolar bone defects between time points T1 and T2. A total of 499 patients were selected for logistic regression analysis to examine the correlation among age, sex, crowding, sagittal facial type, extraction, miniscrew use and fenestration or dehiscence post‐treatment.
Results
Except for the maxillary lingual fenestration and labial fenestration of mandibular canines, a significant change in the prevalence of fenestration and dehiscence was noted between time points T1 and T2 ( P < .025). Multinomial logistic regression showed that age, miniscrew use and extraction highly influenced the prevalence of anterior lingual dehiscence ( P < .05). Dehiscence of the mandibular labial side (skeletal Class III vs. I, OR = 2.368, P = .000) and fenestration of the mandibular lingual side (skeletal Class II vs. I, OR = 2.344, P = .044) were strongly correlated with the sagittal facial type. Dehiscence of the maxillary labial side (moderate vs. mild, OR = 1.468, P = .017) was significantly associated with crowding.
Conclusions
Older age, maxillary moderate crowding, skeletal Class III, extraction and miniscrew potentially significantly affect the prevalence of anterior teeth dehiscence. Adult females, skeletal Class III patients on the mandibular labial side and skeletal Class II patients on the mandibular lingual side should be monitored for anterior teeth fenestration.
We aimed to evaluate root parallelism and the dehiscence or fenestrations of virtual teeth setup using roots isolated from cone beam computed tomography (CBCT) images. Sixteen patients undergoing non-extraction orthodontic treatment with molar distalization were selected. Composite teeth were created by merging CBCT-isolated roots with intraoral scan-derived crowns. Three setups were performed sequentially: crown setup considering only the crowns, root setup-1 considering root alignment, and root setup-2 considering the roots and surrounding alveolar bone. We evaluated the parallelism and exposure of the roots and compared the American Board of Orthodontics Objective Grading System (ABO-OGS) scores using three-dimensionally printed models among the setups. The mean angulation differences between adjacent teeth in root setups-1 and -2 were significantly smaller than in the crown setup, except for some posterior teeth (p < 0.05). The amount of root exposure was significantly smaller in root setup-2 compared to crown setup and root setup-1 except when the mean exposure was less than 0.6 mm (p < 0.05). There was no significant difference in ABO-OGS scores among the setups. Thus, virtual setup considering the roots and alveolar bone can improve root parallelism and reduce the risk of root exposure without compromising occlusion quality.
Objectives
To evaluate alveolar bone dimensions and its relationship with tooth movement (retraction, intrusion and torque) during orthodontic treatment with fixed appliance and clear aligners.
Methods
Thirty‐two patients were included in this retrospective clinical study. Cone beam computed tomography (CBCT) was collected before and after treatment to measure the volume of dehiscence and fenestrations in the maxillary anterior region, anterior alveolar bone thickness and height and degree of tooth movement. Rank‐sum tests were used to compare the differences in alveolar bone defect volumes between clear aligners and fixed appliance, multiple linear regression analysis was used for study evaluation, and kappa statistics were used to assess internal consistency and test‐retest reliability.
Results
Post‐operatively, most alveolar bone defects occurred on the labial side. The incidence of bone fenestration was 23.96% in the clear aligner group and 26.18% in the fixed appliance group, which was higher than the incidence of bone dehiscence (5.21%). The labial bone height decreased by 0.272 mm, and the palatal bone height increased by 0.617 mm for every 1 mm downward intrusion of the anterior tooth apex in the fixed appliance group. In the clear aligner group, there was no significant change in the labial bone height, and the palatal bone height decreased by 0.447 mm for every 1 mm of anterior tooth retraction coronally.
Conclusions
In the fixed appliance group, anterior tooth intrusion and retraction may have led to alveolar bone resorption by its compression at the cervical level. This study provides a three‐dimensional tooth movement evaluation method by using CBCT.
The straight-wire appliance is an individualized, fully-programmed appliance system that has been in clinical use since the early 1970s. A study of tooth positions in individuals with naturally occurring harmonious occlusions led to the discovery of the Six Keys to Normal (Optimal) Occlusion which provided data for bracket features and prescription values incorporated into the straight-wire appliance. It was based on the notion that tooth anatomy, morphology, and optimal positions were alike enough among individuals, regardless of age, sex, or race to justify using prefabricated brackets with average prescription values. New technologies have led to advancements in appliance customization. Customized brackets can be made-to-order with one-of-a-kind prescription values and bracket base contours that fit precisely to the morphologic characteristics of the teeth. If costs and material qualities were comparable, would treatment efficiency or treatment outcomes be superior when using a customized appliance compared with a prefabricated straight-wire appliance? If not, why not?
Background:
Dental malocclusions may cause disruption in occlusal harmony, and destructive interferences during mandibular functional movements can be seen. Ideal occlusal contacts during dynamic mandibular movements may be crucial for preventing the occurrence of mid-buccal gingival recession (mbGR). While determining mbGR risk factors in young adults, the effect of occlusal interferences on mbGR has not yet been focused on. Based on this gap, this field needs to be clarified with new studies.
Objective:
The aim of this case-control study was to evaluate the relationships between the presence, extent and severity of mbGRs to dental malocclusions, occlusal interferences in anterior (AG) and lateral guidance (LG) and to determine the potential risk indicators in a young population.
Methods:
A total of 149 dental students were comprised and 70 of them presented mbGR(s) and 79 did not (18-25 years, 4553 teeth). Periodontal status was assessed with full mouth bleeding (FMBS) and plaque score (FMPS), probing depth (PD), clinical attachment level (CAL), recession depth, and keratinized tissue width (KTW) by a periodontist. Malocclusions and occlusal interferences were evaluated by an orthodontist. Logistic regression analyses provided data on the effect of occlusal interferences and the other indicators towards mbGR.
Results:
The mean of the number of teeth with mbGR(s) per subject was 4.3. The mean of the overall extent of teeth with mbGR(s) was 14.2%. FMBS, decreased KTW, self-reported bruxism, group function occlusion, increased contact number of all teeth and only premolars/molars in AG or LG and Class III malocclusions were significantly associated with the presence of mbGR. Decreased KTW, presenting mbGR in the mandible and non-carious cervical lesion (NCCL) adjunct to mbGR significantly increased the odds of the severity of mbGR. Group function occlusion revealed higher mbGRs in premolar/molars than canine guided occlusion.
Conclusion:
Increase in the occlusal interferences in premolars/molars during lateral and anterior guidance may have an effect on the presence and severity of mbGR. Further studies should be designed to confirm these findings.
The “envelope of discrepancy” to define the limitation of tooth movement is well accepted in orthodontics. However, it has been more for illustrating possibilities of various tooth movement. The described envelopes were not determined by scientific measurements or specific anatomic boundaries. Currently, CBCT imaging has enhanced our ability to evaluate the morphology of the craniofacial and dentoalveolar gingival complex. It allows the quantitative assessment of the dimensions of alveolar bone which could not be evaluated in two-dimensional images due to the superimposition of anatomical structures. The limits of orthodontic tooth movement which is defined as “orthodontic boundary limits” may need to be established, utilizing 3D imaging technology.The purposes of this chapter are to: (1) review the dentoalveolar gingival complex,dentoalveolar bone deficiency, and the dimensional changes of dentoalveolar gingival complex with tooth movement, and (2) challenge to determine the orthodontic boundary limits of mandibular incisors in Skeletal Class II patients.KeywordsSkeletal Class IICone-beam computed tomographyOrthodontic boundary limitsDentoalveolar gingival complexDentoalveolar bone deficiency
Patients who seek orthodontic treatment are present with dental crowding and/or with skeletal discrepancies. When patients with malocclusions resulting from underlying skeletal discrepancies desire treatment, we as orthodontists offer a spectrum of treatment options based on the clinical diagnosis and desired final outcome. As Dr. Morton Amsterdam wrote, for every malocclusion there are multiple treatment modalities but only one correct diagnosis [1]. When the etiology for the malocclusion is skeletally based, a patient’s treatment options include either a combination of orthodontics and orthognathic surgery or orthodontic “camouflage” treatment, including extractions and interproximal reduction [2, 3]. Orthodontists rely on comprehensive orthodontic records, including clinical presentation, periodontal condition, restorative needs, dental models, and radiography including three-dimensional cone beam computed tomography (CBCT) imaging, to help decide which treatment options and modalities are most appropriate for each patient. Using these diagnostic records, a problem list is generated, a diagnosis is developed, and clear treatment objectives are outlined [2, 3]. These objectives will help define which treatment strategies may be appropriate to achieve the desired outcomes.
Introduction
The objective of this study was to explore the effect of augmented corticotomy (AC) on anterior alveolar bone morphology in presurgical orthodontic treatment for skeletal Class III malocclusion.
Methods
Thirty-six surgical patients with skeletal Class III malocclusion with high-angle were included: 18 (AC group) accepted AC surgery during presurgical orthodontic treatment, and 18 (control group) accepted traditional presurgical orthodontic treatment. Cone-beam computed tomography scans were obtained before treatment (T0) and after presurgical orthodontic treatment (T1). The alveolar bone morphology, root length, dehiscence, and movement of mandibular central incisors were measured by cone-beam computed tomography using Dolphin software. Statistical analyses were performed with independent-sample t tests, paired t tests, and multiple linear regression.
Results
After presurgical orthodontic treatment, the whole alveolar bone thickness at each level, alveolar bone area, and alveolar bone height decreased significantly in the control group but increased or remained unchanged in the AC group. In the AC group, the lower the labial alveolar bone height at T0 was, the greater the increase after T1; the change in alveolar bone thickness was related to ΔL1-MP and sex. At T0, the incidences of dehiscence were similar in the 2 groups, ranging from 11.11% to 16.67%. At T1, the labial and lingual incidences of dehiscence in the AC group were 0% and 27.78%, compared with 55.56% and 66.67% in the control group.
Conclusions
During presurgical orthodontic treatment, AC is effective in preventing alveolar bone resorption and dehiscence without additional root resorption. AC can be recommended for high-angle skeletal Class III patients with thin alveolar bone around anterior teeth during presurgical orthodontic treatment.
Objective
The objective of this study was to retrospectively investigate the facial alveolar bone (FAB) thickness and fenestration rate of maxillary first and second premolars using cone-beam computed tomography (CBCT).
Design
A total of CBCT images of 66 patients were selected and 200 maxillary premolar (100 first and 100 second premolar) were included. The FAB thicknesses were measured at 1,3 and 5 mm apical to the alveolar bone peak. The prevalence of fenestration in maxillary premolars was recorded. The statistical analyses were performed.
Results
The FAB thicknesses of the second premolars (1.39 mm at 1 mm, 1.42 mm at 3 mm, and 1.22 mm at 5 mm) were significantly higher than the first premolars (1.11 mm at 1 mm, 0.70 mm at 3 mm, and 0.48 mm at 5 mm) at 1, 3, and 5 mm levels (p<0.05). The lowest prevalence (1%) of the thickness of FAB ≥ 2 mm was in the first premolar has at 5 mm apical of the alveolar bone peak. The overall prevalence of fenestration in maxillary premolars was found as 30.5%. There was a statistically significant difference between first and second premolars (p<0.05).
Conclusion
The FAB thicknesses are lower in the first premolar than the second premolar. The lowest FAB thickness was in the first premolar at 5 mm apical of the bone crest as 0.42 mm. The prevalence of fenestration in maxillary premolars was higher in the Turkish subpopulation than in other populations. Fenestration was more common in the maxillary first premolar.
Objective:
To determine the discrepancy of crown-root morphology of anterior teeth, using cone-beam computed tomography (CBCT), and to provide a guidance for proper torque expression.
Methods:
A total of eligible 200 CBCT were imported into Invivo v. 5.4 software, to obtain the middle labio-lingual sections of anterior teeth. AutoCAD 2007 software was applied to measure the crown-root angulation (Collum angle) and the angle formed by a tangent to the center of the labial surface and the long axis of the crown (labial surface angle). SPSS 18.0 was used for statistical comparisons of the two measurements, at the level of p< 0.05, and the Pearson correlation analysis was applied to investigate the association between the two measurements.
Results:
The value of Collum angle in maxillary central incisor was close to 0°. Significantly negative Collum angle in lateral incisors and maxillary canine, and positive value in mandibular canine were detected (p < 0.001). The labial surface angle in canine was significantly greater than the intra-arch incisors (p< 0.001), and no significant difference was detected between the central and lateral incisors (p > 0.05). Notably, there was also a significant positive correlation between the two measurements.
Conclusions:
The crown-root angulations were greatly different among anterior teeth. Accompanying the obvious crown-root angulations, the canines both in maxillary and mandibular arches presented considerable labial surface curvatures. Hence, equivalent deviation during bracket bonding might cause greater torque expression error and increase the risk of alveolar fenestration and dehiscence.
Purpose: The objective of the study was to explore the effect of periodontally accelerated osteogenic orthodontics (PAOO) in orthodontic patients with bone dehiscence and fenestration in the anterior alveolar region of the mandible.
Methods: A retrospective study was performed in 42 patients with bone dehiscence and fenestrations in the anterior alveolar region of the mandible underwent the PAOO technique. Bleeding index (BI), probing depth (PD), keratinized gingiva width (KGW), gingival recession depth (GRD), and gingival phenotype were recorded and assessed at baseline, postoperative 6 and 12 months. Cone-beam computerized tomography was utilized for bone volume measurement in term of root length (RL), horizontal bone thickness at different levels and vertical bone height at baseline, 6 months and 12 months after the surgery.
Results: The sample was composed of a total of 42 patients (22 males and 20 females; mean age, aged 25.6 ± 4.8 years) with 81 teeth showing dehiscence/fenestrations and 36 sites presenting with gingival recessions. There was no significant difference in BI, PD, and KGW (between baseline, postoperative 6 and 12 months) based on the clinical evaluations (P > 0.05). Gingival recession sites demonstrated a significant reduction in the GRD after surgery (P < 0.05). Besides, the proportion of teeth with thick gingival phenotype was increased from 33.61% at baseline to 53.13% at the end of the follow-up. In addition, the bone thickness at mid-root and crestal level was markedly increased compared with the baseline records (P < 0.05), although the increase in apical level was not statistically significant (P > 0.05). Moreover, alveolar bone height was also remarkably increased at postoperative 6 month compared with the baseline records (P < 0.05).
Conclusions: Within the limitations of the study, the obtained results show that PAOO technique is beneficial to periodontal conditions in terms of soft and hard tissue augmentation. PAOO procedure may represent a safe and efficient treatment for orthodontic patients with bone dehiscence and fenestration.
Trial registration: This study was approved by the ethics committee of stomatological hospital affiliated to Xi'an Jiaotong University (xjkqll[2019]NO.016) and registered in Chinese Clinical Trial Registry (ChiCTR2100053092).
Background/Purpose
Endodontic microsurgery (EMS) is a reliable treatment for teeth with non-healing apical periodontitis. This study evaluated the outcome of EMS with mineral trioxide aggregate as the retrograde filling material and identified potential prognostic factors associated with the EMS outcome.
Methods
Consecutive clinical and radiographic records of EMS performed in a teaching hospital from 2013 to 2017 were reviewed. Cases of root fracture, cemental tear, re-surgery, and incomplete records were excluded. After selection, 268 EMS-treated teeth with the follow-up period more than one year were included. Surgical outcome as success or failure was evaluated according to Molven's criteria. For analysis of potential prognostic factors, multivariate logistic regression was performed followed by bivariate chi-square tests. Stratified analysis was performed to understand the interactions between two prognostic factors.
Results
The overall EMS success rate was 89.9% in this study. Tooth type (anteriors vs. molars, odds ratio (OR) = 6.83, P = 0.001, anteriors vs. premolars, OR = 4.27, P = 0.010) and endodontic-periodontal (endo-perio) communicating defects (with vs. without, OR = 4.92, P = 0.005) both had a significant influence on the EMS outcome. The negative impact of endo-perio communicating defects was closely associated with tooth type. Premolars with endo-perio communicating defects had significantly higher rates of failure.
Conclusion
The EMS outcome is significantly affected by the tooth type and endo-perio communicating defect. The presence of endo-perio communicating defects has a greater negative influence on the success rate for premolars than for anteriors and molars.
Introduction: Computed tomography (CT) permits the visualization of the labial/buccal and lingual alveolar bone. Objectives: This study aimed at reporting and discussing the implications of alveolar bone morphology, visualized by means of CT, on the diagnosis and orthodontic treatment plan. Methods: Evidences of the interrelationship between dentofacial features and labial/buccal and lingual alveolar bone morphology, as well as the evidences of the effects of the orthodontic movement on the thickness and level of these periodontal structures were described. Results: Adult patients may present bone dehis-cences previously to orthodontic treatment, mainly at the region of the mandibular inci-sors. Hyperdivergent patients seems to present a thinner thickness of the labial/buccal and lingual bone plates at the level of the root apex of permanent teeth, compared to hypodi-vergent patients. Buccolingual tooth movement might decentralize teeth from the alveolar bone causing bone dehiscences. Conclusion: The alveolar bone morphology constitutes a limiting factor for the orthodontic movement and should be individually considered in the orthodontic treatment planning. Abstract Keywords: Computed tomography. Alveolar bone. Dehiscence. Orthodontics. IntROduCtIOn Computed tomography (CT) permits the den-tal professional to visualize what the conventional radiographs never showed: the thickness and lev-el of the labial/buccal and lingual alveolar bone.
To evaluate the alveolar bone loss around lower incisors incurred during surgical orthodontic treatment in individuals with mandibular prognathism.
The samples consisted of 25 patients (13 men, 12 women; mean ages: 26.3 ± 2.7 years) treated with jaw surgery and orthodontic treatment. Lateral and frontal cephalograms and cone-beam computed tomography (CBCT) images of the patients were obtained before treatment (T0) and after presurgical orthodontic treatment (T1) and after debonding (T2). After measurement of variables, repeated-measures analysis of variance with Bonferroni's multiple comparison test and Pearson and Spearman correlation analysis were performed.
The lower central and lateral incisors showed that the vertical alveolar bone level and the alveolar bone thickness of the labial and lingual plates were reduced after presurgical orthodontic treatment but were not deteriorated during postsurgical orthodontic treatment.
Excessive forward movement of lower incisors during presurgical orthodontic treatment could cause alveolar bone loss around the lower incisors; thus, special care should be considered in individuals with mandibular prognathism.
One of the main points in Orthodontic studies is the growth and development of the craniofacial structures. In this study, skeletal cephalometric characteristics of Class II, division 1 malocclusion were assessed in lateral cephalograms. The experimental sample comprised 55 white Brazilian individuals of both genders, with an ANB angle of 4.5 degrees or higher. The mean age of the subjects was 13.5 years. Steiner and McNamara Jr cephalometric analyses were used in order to evaluate the relation between angular and linear positions of the apical bases, the dental and cranial structures, comparing with the values obtained in the control group (available at Bauru Dental School-USP). The results showed that, for the experimental group, the maxilla was well positioned in relation to the cranial base. The maxillomandibular relation showed an increased overjet, which was predictable based on criteria for sample selection. The geometrical proportion of the apical bases presented a small mandible and a normal sized maxilla. The craniofacial growth pattern presented a vertical tendency. The maxillary incisors were buccally inclined and well positioned by the linear evaluation. The mandibular incisors showed marked buccal inclination and protrusion. No statistically significant difference between genders was found.
The aim of the present study was to assess the relationship between the maxillary sinus floor and the maxillary posterior teeth root tips using dental cone-beam CT.
A total of 87 right and 89 left maxillary sinus regions from 92 patients were examined using dental cone-beam CT. Images were analyzed by a specialist in oral and maxillofacial radiology. Perpendicular lines were drawn on the cross-sectional images between the deepest point of the maxillary sinus floor and the root tips of the maxillary first and second premolars and first, second and third molars, and the distances were measured using built-in measurement tools. Means, standard deviations and minimum and maximum values were calculated for all right and left premolars and molars. T-tests were used to compare measurements between left and right sides and between female and male patients.
The distance between sinus floor and root tip was longest for the first premolar root tip and shortest for the second molar buccodistal root tip for both right and left sides. No statistically significant differences were found between the right and left side measurements or between female and male patients (P>.05).
Knowledge of the anatomical relationship between the maxillary sinus floor and the maxillary posterior teeth root tips is important for the preoperative treatment planning of maxillary posterior teeth.
In this study, we aimed to verify, via computed volumetric tomography, a correlation between the morphology of the mandibular symphysis and the various facial types.
From a sample of 148 digital volumetric tomographs, the subjects were classified as either short face (25 subjects), normal face (27 subjects), or long face (28 subjects) according to the average values of their Frankfort-mandibular plane angle. The 80 healthy subjects were between 12 and 40 years of age. Tomography was carried out using NewTom 3G volume scanner (QRsr1, Verona, Italy). The following parameters were measured on the sections corresponding to the 4 mandibular incisors: height, thickness, and area of the entire symphysis; height, thickness, and area of the cancellous bone of the symphysis; distance of the vestibular and lingual cortices from the apices of the 4 incisors; and possible inclination of each mandibular incisor, expressed in degrees. The F test or analysis of variance (ANOVA) and the Tukey HSD Test were subsequently used.
The total thickness of the symphysis was greater in the short-face subjects than in the long-face subjects. No statistically significant differences in the total and cancellous areas of the symphysis were found between the 3 facial types. In all 3 groups, the total and cancellous heights and areas were greater at the central incisors than at the lateral incisors.
There is a statistically significant relationship between facial type and the total thickness of the mandibular symphysis.
The aim of this study was to compare the presence of alveolar defects (dehiscence and fenestration) in patients with Class I and Class II Division 1 malocclusions and different facial types.
Seventy-nine Class I and 80 Class II patients with no previous orthodontic treatment were evaluated using cone-beam computed tomography. The sample included 4319 teeth. All teeth were analyzed by 2 examiners who evaluated sectional images in axial and cross-sectional views to check for the presence or absence of dehiscence and fenestration on the buccal and lingual surfaces.
Dehiscence was associated with 51.09% of all teeth, and fenestration with 36.51%. The Class I malocclusion patients had a greater prevalence of dehiscence: 35% higher than those with Class II Division 1 malocclusion (P <0.01). There was no statistically significant difference between the facial types.
Alveolar defects are a common finding before orthodontic treatment, especially in Class I patients, but they are not related to the facial types.
The present study was undertaken to determine quantitatively the accuracy of modern high-resolution computed tomography (HR-CT) in imaging periodontal defects in vitro by means of comparative radiological and histological studies. The soft tissue and metallic restorations were removed from four mandibular and maxillary jaw segments. Eighteen lingual and buccal defects of different dimensions were artificially created over the roots of the teeth. Dental radiographs and 1.0 mm contiguous axial and coronal HR-CT scans were obtained. Histological specimens were prepared in the same plane as the CT scans. A quantitative analysis of the periodontal regions on the CT scans was feasible when the alveolar bone was 0.5 mm thick. A visible periodontal ligament space was found to improve the reliability of the measurement of buccal or lingual bone plates up to 0.2 mm thick or of the artificial dehiscences. In the axial HR-CT scans, 70% of the artificial defects could be identified. and in the coronal scans, 50%. In contrast, none of the defects could be evaluated on conventional dental radiographs. It is concluded that HR-CT scanning could be useful in assessing buccal and lingual alveolar bone morphology and in diagnosing larger dehiscences.
The biological response to orthodontic tooth movement has generally focused on reactions within the periodontal ligament (PDL), whereas less attention has been paid to the behavior of neighboring bone. The purpose of the study was to describe the influence of orthodontic force on bone surrounding the displaced tooth and the adjacent, untreated teeth. Bone changes in relation to treatment time and different sites were investigated. A mesial tipping of the left maxillary first molar was obtained from 54 adult male Wistar rats. Oxytetracycline was injected subcutaneously 48 h before killing, which took place after 4, 7, or 14 days. The maxilla was fixed in paraformaldehyde and embedded undecalcified in methylmethacrylate. A set of thick horizontal sections was taken from the cervical, intermediate, and apical levels of the roots. The sections were microradiographed and analyzed microscopically under bright-field and fluorescent illumination. Bone fraction and PDL width was measured using a Zeiss Videoplan device equipped with an overlay system. New bone formation was detected by oxytetracycline labels. The analysis showed a consistent, significant decrease of the alveolar bone fraction around both displaced and adjacent teeth at all treatment times. Apposition, indicated by the tetracycline uptake, was found on the periosteal side of the treated hemimaxilla and, after 14 days, also on the surface toward which the tooth was moving and around the adjacent teeth. These results suggest that a time rather than a space relationship exists between bone resorption and formation and that the whole hemimaxilla reacts to the mechanical challenge, resembling the regional acceleratory phenomenon (RAP) observed in other circumstances.
PERIODONTAL DISEASES ARE INFECTIONS, and many forms of the disease are associated with specific pathogenic bacteria which colonize the subgingival area. At least two of these microorganisms, Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans, also invade the periodontal tissue and are virulent organisms. Initiation and progression of periodontal infections are clearly modified by local and systemic conditions called risk factors. The local factors include pre-existing disease as evidenced by deep probing depths and plaque retention areas associated with defective restorations. Systemic risk factors recently have been identified by large epidemiologic studies using multifactorial statistical analyses to correct for confounding or associated co-risk factors, Risk factors which we know today as important include diabetes mellitus, especially in individuals in whom metabolic control is poor, and cigarette smoking. These two risk factors markedly affect the initiation and progression of periodontitis, and attempts to manage these factors are now an important component of prevention and treatment of adult periodontitis. Systemic conditions associated with reduced neutrophil numbers or function are also important risk factors in children, juveniles, and young adults. Diseases in which neutrophil dysfunction occurs include the lazy leukocyte syndrome associated with localized juvenile periodontitis, cyclic neutropenia, and congenital neutropenia. Recent studies also point to several potentially important periodontal risk indicators. These include stress and coping behaviors, and osteopenia associated with estrogen deficiency. There are also background determinants associated with periodontal disease including gender (with males having more disease), age (with more disease seen in the elderly), and hereditary factors. The study of risk in periodontal disease is a rapidly emerging field and much is yet to be learned. However, there are at least two significant risk factors-smoking and diabetes-which demand attention in current management of periodontal disease.
The mandible of a deceased 19-year-old young woman who had been treated with an edgewise appliance was removed during autopsy. The overall tooth movements during the 19 months of treatment were reconstructed (treatment documents) and compared with the macroscopic, radiologic, and micromorphologic findings of the incisor/alveolar bone/symphysis complex of the dry mandible. The initial lateral cephalogram revealed an extremely narrow and high symphysis, with an incisor position straight above the thin bone. During treatment, the incisors had been moved to lingual (lingual root torque) and derotated. Morphologic evaluation of the dry mandible revealed lingual (oral) aspects of the roots reaching some millimeters out of the lingual alveolar bone and largely without cortical plate covering, Lateral dental contact radiographs of any bone/incisor segment showed the sagittal alveolar bone width to be smaller than the labiolingual (orobuccal) diameter of the incisor roots. A comparison of the approximate pretherapeutic alveolar bone height, which was assessed by measuring the distance from the cementoenamel junction to the most coronal margin of any root resorption in scanning electron microscopy, with that of the specimen showed a calculated bone loss on the lingual aspect extending from 2.3 to 6.9 mm. On the labial (buccal) aspect, bone loss was far less pronounced. These results suggest that in the case of a narrow and high symphysis, pronounced sagittal incisor movements and derotation during routine orthodontic treatment with a fixed appliance may be critical and lead to progressive bone loss of lingual and labial cortical plates.
In 21 adult patients, two or three high-resolution computed tomography(HR-CT) examinations were performed before, during and after orthodontic treatment with fixed appliances. The time between the first, second, and third CT scanning varied according to the individual treatment or retention period from 12 to 36 months. Comparison of the CT examinations permits three-dimensional evaluation of osteoblastic and osteoblastic periodontal remodeling. The incidence of periodontal lesions, such as bone dehiscenses, fenestrations and root resorptions were assessed in relation to the initial periodontal situation and the applied orthodontic biomechanics. Anatomic risks were a small alveolar process, thin buccal or lingual bone plates, eccentric positioning of teeth, basally extended maxillary sinus, and progressive alveolar bone loss. Therapeutic risks were uncontrolled sagittal or vertical movements of the incisors and cortical or intermaxillary anchorage preparation. Orthodontically induced bone dehiscences were partly repaired by osteoblastic periodontal remodeling in the retention period.
In a clinical study of 11 adult patients, HR-CT-examinations were performed before or during and after orthodontic treatment with fixed appliances. The treatment period between the first and second CT-scanning varied from 12 to 24 months. Comparison of the first and second CT-examination permits three-dimensional evaluation of osteoclastic and osteoblastic alveolar remodeling. The incidence of periodontal lesions such as bone dehiscences, fenestrations and root resorptions was assessed in relation to the initial periodontal situation and the orthodontic treatment concept. Anatomical risks were a small alveolar process, thin buccal or lingual bone plates, eccentric position of teeth, basally extended maxillary sinus and progressive alveolar bone loss. Therapeutic risks were uncontrolled sagittal or vertical movements of incisors and cortical or intermaxillary anchorage preparation. CT-scanning of the alveolar process during orthodontic treatment with HR-CT allows three-dimensional interpretation of the alveolar osteodynamics, especially the development and repair of orthodontically induced bone dehiscences in relation to tooth movement.
The aim of this study was to test the null hypothesis that there is no difference in the alveolar bone thickness, bone loss or incidence of fenestrations between upper and lower incisors in skeletal Class I bidentoalveolar protrusive patients before orthodontic treatment.
Three-dimensional (3D) cone beam CT (CBCT) images were taken of 24 patients from the Republic of Korea (17 females and 7 males). Reformatted CBCT images were used to measure labial and lingual alveolar bone thickness (ABT) of the 4 upper incisors and 4 lower incisors of the 24 patients (total n = 192 incisors) at every 1/10 of root length (Level 0, cementoenamel junction (CEJ) area; Level 10, root apex area) as well as alveolar bone area (ABA) and alveolar bone loss (%BL) rate to dental root length. The numbers of fenestration teeth were also tallied.
All anterior teeth were supported by <1 mm of ABT on the labial surfaces up to root length Level 8. ABA was statistically greater on the lingual aspect than the labial aspect in lower incisors. The %BL was 26.98% in the lower labial region, 19.27% in upper labial aspect and most severe on the lower lingual plate 31.25% compared with the labial plate. There were no significant differences in %BL between subgroups when categorized by sex or age. Fenestrations were 1.37 times more frequent on lower incisors (37) than upper incisors (27).
The null hypothesis was rejected, confirming that incisor periodontal support is poor and alveolar bone loss is severe even prior to the start of orthodontic treatment. Careful diagnosis using 3D CBCT images is needed to avoid iatrogenic degeneration of periodontal support around anterior teeth, particularly in the lower lingual bone plate region.
To test the hypothesis that there is no difference in vertical alveolar bone loss and alveolar bone thickness around maxillary and mandibular central incisors in normal occlusion samples and skeletal Class III malocclusion patients.
The study sample comprised 20 Korean normal occlusion subjects (mean age, 22.1 years; group 1) and patients with skeletal Class III malocclusion with anterior open bite (mean age, 22.4 years; group 2). Three-dimensional (3D) cone beam computed tomography (CBCT) images were taken before orthodontic treatment, and sagittal slices chosen at the labio-lingually widest point of the maxillary and mandibular right central incisor were evaluated, respectively. The amount of vertical alveolar bone loss and/or alveolar bone thickness of the labial and lingual plate at the root apex were measured.
Group 2 had statistically significant more vertical bone loss than group 1 (P < .05). Alveolar bone at the apex was significantly thinner in group 2 (P < .05), except for the maxillary incisors. Mandibular incisors showed greater alveolar bone loss than was seen in maxillary incisors in both groups, especially at the lingual side in group 2 (P < .05). Overall, alveolar bone thickness at the apex was wider than cementoenamel junction (CEJ) width, except for the mandibular incisors in group 2, for which the percentage was 81.33%.
The hypothesis is rejected. Special care should be taken to avoid aggravating preexisting alveolar bone loss in the anterior teeth, especially in the mandible, in skeletal Class III patients, who may be more vulnerable to alveolar bone loss during orthodontic treatment.
The purpose of this study was to evaluate the accuracy and reliability of cone-beam computed tomography (CBCT) in the diagnosis of naturally occurring fenestrations and bony dehiscences. In addition, we evaluated the accuracy and reliability of CBCT for measuring alveolar bone margins.
Thirteen dry human skulls with 334 teeth were scanned with CBCT technology. Measurements were made on each tooth in the volume-rendering mode from the cusp or incisal tip to the cementoenamel junction and from the cusp or incisal tip to the bone margin along the long axis of the tooth. The accuracy of the CBCT measurements was determined by comparing the means, mean differences, absolute mean differences, and Pearson correlation coefficients with those of direct measurements. Accuracy for detection of defects was determined by using sensitivity and specificity. Positive and negative predictive values were also calculated.
The CBCT measurements showed mean deviations of 0.1 +/- 0.5 mm for measurements to the cementoenamel junction and 0.2 +/- 1.0 mm to the bone margin. The absolute values of the mean differences were 0.4 +/- 0.3 mm for the cementoenamel junction and 0.6 +/- 0.8 mm for the bone margin. The sensitivity and specificity of CBCT for fenestrations were both about 0.80, whereas the specificity for dehiscences was higher (0.95) and the sensitivity lower (0.40). The negative predictive values were high (>or=0.95), and the positive predictive values were low (dehiscence, 0.50; fenestration, 0.25). The reliability of all measurements was high (r >or=0.94).
By using a voxel size of 0.38 mm at 2 mA, CBCT alveolar bone height can be measured to an accuracy of about 0.6 mm, and root fenestrations can be identified with greater accuracy than dehiscences.
Gingival recession (GR) is a commonly observed dental lesion. The underlying etiology has not been clearly identified, although several theories have been suggested. Tooth crowding or tooth malalignment is also frequently observed, with both conditions appearing to be more prevalent in developed countries with heterogeneous populations.
A total of 25 consecutively treated patients representing 72 teeth and demonstrating facial clinical GR of > 3 mm were examined clinically, photographically, and with 3-dimensional radiology using conebeam computed tomography. All examined teeth presented with normal interproximal probing depths and attachment levels (< 4 mm). Tooth position or tooth volume plus the associated adjacent alveolar bone volume and GR were analyzed. This group was further evaluated during periodontal surgery for associated alveolar bone fenestrations or dehiscences.
All teeth demonstrating > 3 mm of GR presented with significantly prominent facial tooth contours and associated alveolar bone dehiscences. Most involved teeth presented with their root structures extending beyond the facial alveolar bony housing (fenestrations). This represents a discrepancy between tooth size and alveolar bone dimensions in the buccolingual, axial, and sagittal orientation. Fewer involved teeth were malpositioned toward the buccal aspect. Both conditions were associated with facial alveolar bone dehiscences and associated GR.
This study suggests tooth volume and/or tooth position within the alveolar bony housing strongly correlate with GR. All nonperiodontitis-involved teeth with GR were associated with either wider teeth or facially aligned teeth. However, it is emphasized that all facially aligned teeth, or "larger" teeth, do not necessarily present with GR. Based on these findings, the radiographic-supporting bone index is proposed. This index should facilitate appropriate evaluation of the alveolar bone supporting the mucogingival complex, both on the facial and lingual aspect of teeth. Further investigations are needed to support these preliminary data.
To test the null hypothesis that there are no correlations between the morphology of the upper jaw, the position of the upper incisors, and facial type.
From a sample of 191 patients, the FMA angle was used to select 20 short face type, 20 norm face type, and 20 long face type patients, aged 12 to 40 years. Using cone-beam computed tomography (CBCT), tomography was carried out on sagittal sections corresponding to the four upper incisors. Some parameters defining the dentoskeletal relationships, the alveolar thickness, the alveolar height, and the dental movement were measured. The measurements were processed using analysis of variance and Tukey's test.
At the upper central incisors, short face type patients presented a greater alveolar bone thickness than long face type patients. In short face type and norm face type subjects the root apex of the upper incisors was farther away from the lingual cortex than in the long face type patients. At the central incisors the alveolar thickness was greater and the lingual cortex was higher with respect to the lateral incisors in all three facial types.
At the upper incisors, facial type is statistically significantly correlated with both alveolar bone thickness and distance between the root apex and lingual cortex.
To test the hypothesis that there is no difference in the vertical alveolar bone levels and alveolar bone thickness around the maxillary and mandibular central incisors in surgically treated skeletal Class III malocclusion patients.
The study sample comprised 20 Korean patients with skeletal Class III malocclusion with anterior crossbite and openbite (9 male, 11 female, mean ages 24.1). Three-dimensional cone beam computed tomography images were taken at least 1 month before the orthognathic surgery, and sagittal slices chosen at the labio-lingually widest point of the maxillary and mandibular right central incisor were evaluated. Measurement of the amount of vertical alveolar bone levels and alveolar bone thickness of the labial and lingual plate at the root apex was made using the SimPlant Pro 12.0 program.
The mandibular incisors showed reduced vertical alveolar bone levels than the maxillary incisors, especially on the lingual side. The alveolar bone thickness was significantly greater on the lingual side in the maxillary incisors, whereas the mandibular incisors exhibited an opposite result (P < .05). The percentage of vertical bone loss to root length showed a statistically significant difference between the upper labial and lower labial alveolar bone and also between the upper lingual and lower lingual alveolar bone, showing more bone loss in the lower incisors (P < .001).
The hypothesis is rejected. For the skeletal Class III patients undergoing orthognathic surgery, special care should be taken to prevent or not aggravate preexisting alveolar bone loss in the anterior teeth, especially in the mandible.
The purpose of this study is to assess cortical thickness, height, and width with cone-beam computed tomography (CBCT), and determine the relationship of these parameters with age.
A total of 113 subjects from the University of California at San Francisco Orthodontic Clinic with a CBCT scan were enrolled. Subjects were stratified by age in decades. Thickness of buccal and lingual cortices and mandibular height and width were evaluated in 5 regions (13 sites). A single factorial ANOVA was used to compare the parameters among age groups. P less than or equal to .05 was statistically significant.
There were 44 (38.9%) males; 69 females. For all groups, the thickest to the least thick cortical plates were: base of the mandible, lower buccal one third, upper lingual one third, upper buccal one third, and lower lingual one third. In all groups, the mandible increased in height as the midline was approached, and the width of the upper third of the mandible decreased from the second molar to the symphysis whereas the reverse occurred in the lower third. Comparison of the age groups showed that subjects 10 to 19 years old had thinner cortical plates than other age groups (P <or= .05) with peak thickness in subjects 40 to 49 years old. The subjects 10 to 19 years old also had lower posterior mandibular height (P <or= .05). There was no statistical difference in width among the groups.
The mandibular cortical bone is thickest at the base, on the buccal side. Subjects who are 10 to 19 years old have thinner cortical bone and decreased mandibular height compared with all other age groups. The mandible continues to mature through 40 to 49 years of age and then decreases in thickness after this period.
Orthodontic treatment may in some cases initiate damage to teeth and supporting tissues (decalcification and gingivitis) or root resorption, pulp damage, allergic reactions, or craniomandibular dysfunction. This review updates some interesting findings regarding these problems.
The proliferation of cells is regulated by countervailing positively- and negatively-acting signaling networks. The anti-proliferative signals, the study of which has been much neglected until recently, are often conveyed by growth-inhibitory peptides. Elements that mediate the cellular response to growth inhibitors are encoded by tumor suppressor genes that if lost may lead to the runaway growth of the cancer cell.
The mechanisms controlling iatrogenic external root resorption (ERR) and repair were studied on 8 Macaca fascicularis monkeys. The animals were divided into short-term and long-term groups, and were treated with jackscrew, magnetic and sham palatal expansion appliances. Scanning electron microscopy morphometric analysis found major evidence of ERR in the tooth-borne jackscrew appliance, in the long-term group, in the maxillary premolars, on the buccal and furcation root surfaces, on the mesiobuccal root, and in the apical zone. Correspondingly, the ERR mechanism is controlled by the impulse (F. delta t) and the critical barrier of the periodontal ligament as primary determinants and by the environmental density as a secondary determinant. ERR is initially regulated by the force component of the impulse and, with increased duration, by the time component of the impulse. The impairment/repair dynamics were found to be regulated by three principles: ERR level of irreversibility, delayed resorption response and jiggling.
The purpose of this study is to examine associations between facial morphology and malocclusion, and to test for sexual dimorphism in such relationships. The sample of 500 subjects is studied by roentgenographic cephalometry, using the Facial Height Ratio (FHR) of Jarabak as the mensurational approach to describe craniofacial morphology. Significant findings are: Neutral pattern is dominant in Class I and Class II1 malocclusions. Hypodivergent pattern is dominant in Class II2 and Class III malocclusions. The majority of females demonstrate a neutral pattern, whereas the majority of males demonstrate a hypodivergent pattern. Sexual dimorphism in pattern is greatest in Class II1 and Class III. Males show a greater tendency toward prognathism, while females tend toward orthognathism and retrognathism. Mean values of all linear measurements in males are larger than in females. Relatively strong correlations are found between facial height ratio and ramus height, gonial angle, lower gonial angle, mandibular plane angle, occlusal/mandibular plane angle, palatal/mandibular plane angle, Frankfurt/mandibular plane angle, S-N-B, Y-axis angle, and the sum of the saddle + articular + gonial angles.
Orthodontic forces can be treated mathematically as vectors. When more than one force is applied to a tooth, the forces can be combined to determine a single overall resultant. Forces can also be divided into components in order to determine effects parallel and perpendicular to the occlusal plane, Frankfort horizontal, or the long axis of the tooth. Forces produce either translation (bodily movement), rotation, or a combination of translation and rotation, depending upon the relationship of the line of action of the force to the center of resistance of the tooth. The tendency to rotate is due to the moment of the force, which is equal to force magnitude multiplied by the perpendicular distance of the line of action to the center of resistance. The only force system that can produce pure rotation (a moment with no net force) is a couple, which is two equal and opposite, noncolinear but parallel forces. The movement of a tooth (or a set of teeth) can be described through the use of a center of rotation. The ratio between the net moment and net force on a tooth (M/F ratio) with reference to the center of resistance determines the center of rotation. Since most forces are applied at the bracket, it is necessary to compute equivalent force systems at the center of resistance in order to predict tooth movement. A graph of the M/F ratio plotted against the center of rotation illustrates the precision required for controlled tooth movement.
To identify the skeletal and dental relationships of adults who have class III malocclusion, lateral cephalograms of 302 adult patients who had a class III molar and cuspid relationship were traced. Ninety-four of the patients had had presurgical orthodontic treatment and 208 had not. The tracings were digitized, and the following sets of measures were analyzed: maxillary skeletal position; maxillary dentoalveolar position; mandibular dentoalveolar position; and mandibular skeletal position. In addition, the mandibular plane angle and lower anterior facial height were measured as an indicator of vertical facial dimensions. None of these values demonstrated significant gender differences except lower anterior facial height; therefore, the subjects were treated as a group. Although there was considerable variation among patients, the most common combination of variables was a retrusive maxilla, protrusive maxillary incisors, retrusive mandibular incisors, a protrusive mandible, and a long lower facial height.
The anterior teeth of five adult pigtail monkeys were moved lingually to correct a previously induced extreme labial displacement. (Roots had been moved through the labial bone to create bone dehiscence, loss of attachment, and gingival recession.) Eight months later, repositioning was performed with fixed appliances (Fig. 3). The teeth were retained in their more normal arch position for 5 months, after which clinical and histologic measurements were made of several periodontal parameters. The canines were not moved and served as reference teeth. Measurements were made to record changes in the levels of the gingival margin, the mucogingival junction, and the marginal bone relative to a fixed point on the tooth crowns, and the width of keratinized gingiva. Oxytetracycline was administered three times to label areas of osteogenesis in the periodontium. The incisors were retracted lingually a mean of 1.8 mm. The marginal bone level increased (moved coronally) a mean of 2.5 mm. and 3.1 mm. for maxillary and mandibular incisors, respectively (Table II). The tetracycline labels showed that osteogenesis occurred in the periodontium to a significant degree. The anchor canines had a loss of 1.1 mm. marginal bone (moved apically). Effects on gingival clefts and keratinized gingiva were slight. These observations demonstrate that in monkeys reapposition of labial bone can occur in a coronal direction, once teeth in extreme labial position with bone dehiscence and gingival recession are moved to a more normal environment. The effects on the periodontal soft tissues (width of keratinized gingiva, recession, attachment level) were, on the other hand, negligible in this study.
In this in vitro study we compared high resolution computed tomography (HR-CT) with dental radiographs regarding the interpretation of horizontal and vertical alveolar bone loss. After removal of the soft tissue and metallic restorations of 20 dentate upper and lower jaw segments 40 infra-alveolar bony defects of different dimensions were experimentally produced. The specimens were examined radiographically with standardized dental radiographs and 1.0 mm thick contiguous axial CT-scans. On the specimens, radiographs and CT-scans the bone loss was measured between the cemento-enamel junction and the adjacent alveolar bone level of 472 mesial and distal tooth surfaces; the identification, classification and vertical depth of the infra-alveolar bony defects were also compared. An average underestimation of 0.6 mm of horizontal alveolar bone loss in the dental radiographs and an overestimation of 0.2 mm in CT-scanning was shown. No significant differences between the imaging accuracy of horizontal alveolar bone loss between dental radiographs and CT-scanning could be evaluated. In the dental radiographs 24 (60%) of the infra-alveolar bony defects could be identified and the vertical depth was underestimated by a mean of 2.2 mm. In comparison, all 40 (100%) infra-alveolar defects could be identified in the CT-scans and the vertical depth was underestimated by an average of 0.2 mm. The HR-CT-technique offers a three-dimensional interpretation of the alveolar morphology without overlying structures. This permits a high identification rate and classification of infra-alveolar bone loss according to the number of surrounding bone walls into one-, two or three-walled bony pockets.
Unlabelled:
The maxilla of a deceased 19-year-old young woman who had been treated with a fixed appliance was removed during autopsy. The sagittal movements of the incisors could be reconstructed by using the treatment records, which were also at our disposal. The anterior segment of the specimen was prepared histologically in the sagittal plane and stained with toluidine blue.
Results:
The tooth movements were executed in two phases: an uncontrolled tipping (root movement to vestibular) was followed by palatinal root torque. The histologic changes, induced by the palatinal root torque were (1) root resorption with apical slope from facioapical to orocoronal, and (2) pronounced subperiosteal bone apposition (palatinal) with partial protrusion of the cortical plate thinning toward coronal. No osseous perforations occurred. The extent and the localization of root resorptions were not verified in the orthoradial x-ray film of the specimen.
The aim of this study was to evaluate the effect of orthodontic tooth movement on the level of the connective tissue attachment in sites with infrabony pockets. The experiment was carried out in four beagle dogs. The second and fourth premolars were extracted. After healing, angular bony defects were prepared at the mesial aspect of the third premolars. The exposed root surface was scaled and planed, and a notch was prepared at the bottom of the defect. Plaque-collecting cotton floss ligatures were placed around the neck of the teeth and maintained in situ for 3 weeks, followed by an additional 2 months of plaque accumulation before the orthodontic tooth movement was initiated. In each dog, one premolar was moved away from the angular bony defect and one premolar into and through the angular bony defect. The maxillary third premolars served as control teeth and were not subjected to orthodontic tooth movement. After orthodontic treatment (5 to 6 months), the teeth were stabilized for a period of 2 months before biopsy sampling. Clinical, radiographic, and histologic evaluations revealed that it was possible to establish and maintain an infrabony pocket with a subcrestal, plaque-induced inflammatory lesion during the entire course of the study. While the control teeth had maintained their attachment levels, all but one of the orthodontically moved teeth showed additional loss of attachment.(ABSTRACT TRUNCATED AT 250 WORDS)
Delineating the limits of orthodontic treatment in nongrowing individuals is important when making treatment decisions, especially in borderline orthodontic-surgical cases. The labial and lingual cortical plates at the level of the incisor apex may represent the anatomic limits of tooth movement. Cephalometric films of 107 adults were measured to determine the width of alveolar bone anterior and posterior to the incisor apex in each arch. Thin alveolar widths were found both labial and lingual to the mandibular incisors in groups of Class I, II, and III individuals with high SN-MP angle and in a group of Class III average SN-MP individuals. Thin alveolar widths were also found lingual to the maxillary incisors in a Class II high angle group. Clinical cases are presented showing that orthodontic tooth movement may be limited in patients with narrow alveolar bone widths and that these patients are likely to experience increased iatrogenic sequelae.
In a clinical study of 11 adult patients, HR-CT-examinations were performed before or during and after orthodontic treatment with fixed appliances. The treatment period between the first and second CT-scanning varied from 12 to 24 months. Comparison of the first and second CT-examination permits three-dimensional evaluation of osteoclastic and osteoblastic alveolar remodeling. The incidence of periodontal lesions such as bone dehiscences, fenestrations and root resorptions was assessed in relation to the initial periodontal situation and the orthodontic treatment concept. Anatomical risks were a small alveolar process, thin buccal or lingual bone plates, eccentric position of teeth, basally extended maxillary sinus and progressive alveolar bone loss. Therapeutic risks were uncontrolled sagittal or vertical movements of incisors and cortical or intermaxillary anchorage preparation. CT-scanning of the alveolar process during orthodontic treatment with HR-CT allows three-dimensional interpretation of the alveolar osteodynamics, especially the development and repair of orthodontically induced bone dehiscences in relation to tooth movement.
This clinical study was designed to investigate early orthodontic movement of human premolars subjected to a controlled, continuous, horizontally directed force. The maxillary right, first or second premolar in 56 children, 18 boys and 38 girls (mean age 13.8 years), was moved buccally with a fixed orthodontic appliance with a frontal bite-block disengaging the occlusion. The contralateral premolar served as control. A weekly controlled and reactivated force of 50 cN (approximately 50 gm) was applied. The force declined on average about 24% per week. The patient material was subgrouped to comprise eight patients in each of seven groups, for which the experimental periods varied from 1 to 7 weeks. Tooth displacement was studied on dental casts, with a coordinate measuring machine (Validator 100, TESA SA, Renens, Switzerland), which made it possible to measure the displacement in three dimensions. The movement pattern of the test teeth was found to be a combination of horizontal and vertical displacements, including tipping. The horizontal movement of the tooth crown was on average 0.8 mm during the first week and 3.7 mm after 7 weeks. The vertical movements were intrusive in 45% and extrusive in 55% of the teeth. In some tipping movements, the crown was "intruded" at the same time as the apex was "extruded." The individual variations in tooth displacements were considerable. The clinical experimental model used permits detailed study of orthodontic tooth movement under controlled force conditions, as well as detailed histologic analysis of related root resorption.
Peridontal diseases are infections, and many forms of the disease are associated with specific pathogenic bacteria which colonize the subgingival area. At least two of these microorganisms, Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans, also invade the periodontal tissue and are virulent organisms. Initiation and progression of periodontal infections are clearly modified by local and systemic conditions called risk factors. The local factors include pre-existing disease as evidenced by deep probing depths and plaque retention areas associated with defective restorations. Systemic risk factors recently have been identified by large epidemiologic studies using multifactorial statistical analyses to correct for confounding or associated co-risk factors. Risk factors which we know today as important include diabetes mellitus, especially in individuals in whom metabolic control is poor, and cigarette smoking. These two risk factors markedly affect the initiation and progression of periodontitis, and attempts to manage these factors are now an important component of prevention and treatment of adult periodontitis. Systemic conditions associated with reduced neutrophil numbers or function are also important risk factors in children, juveniles, and young adults. Diseases in which neutrophil dysfunction occurs include the lazy leukocyte syndrome associated with localized juvenile periodontitis, cyclic neutropenia, and congenital neutropenia. Recent studies also point to several potentially important periodontal risk indicators. These include stress and coping behaviors, and osteopenia associated with estrogen deficiency. There are also background determinants associated with periodontal disease including gender (with males having more disease), age (with more disease seen in the elderly), and hereditary factors. The study of risk in periodontal disease is a rapidly emerging field and much is yet to be learned. However, there are at least two significant risk factors-smoking and diabetes-which demand attention in current management of periodontal disease.
The objectives of the present investigation were to analyze intraoral radiographs and to study 1) the distribution of the distance between the cemento-enamel junction (CEJ) and the alveolar bone level (BL) and 2) the prevalence and severity of vertical defects, and furcation lesions in 416 individuals seeking dental care. Full mouth radiographs were enlarged 7.5 times and the mesial and distal distances between CEJ and bone level were measured. The extent of interradicular molar radiolucencies was also measured. Images of 10,282 teeth were studied. Subjects were between 15 to 94 years (mean age: 47.2, S.D.+/-15.2). On average they had 24.8 teeth (S.D.+/-5.5). The mean distance CEJ-BL increased significantly up to age 45 (r2=0.07; beta=0.29; P < 0.0001) and remained stable thereafter r2=0.09, beta=-0.02, N.S.). The mean distance CEJ-bone level was 1.4 mm (S.D.+/-0.7) in the 15 to 24 age group; 3.0 (S.D.+/-1.5) in the 45 to 54 age group; and 3.02 (S.D.+/-1.4) in the 75 to 94 age group. No vertical defects were found in 163 participants (39.3%); vertical defects > or = 3.0 mm were found in 30.2% (126). Mesial defects were significantly more common that distal defects (P < 0.001). The extent of horizontal bone loss was correlated to extent of vertical defects (r2=0.88; P < 0.0001). The number of remaining teeth was not associated with horizontal or vertical bone loss. In conclusion, the study indicated that few of the individuals had extensive horizontal bone loss. Vertical defects suitable for guided tissue regeneration procedures however, were found in many patients.
The validity of the postulate "bone traces tooth movement" was examined on 40 Angle Cl II cases. It was hypothesized that a 1:1 cortical bone remodeling/tooth movement ratio is preserved during maxillary incisor retraction. The sample was divided into retraction with tip (13 patients), retraction with torque (18 patients), and control (9 patients) groups. Two time point cephalograms were analyzed with two superimposition techniques, SN at S and a newly developed static tooth analysis, with the maxillary left central incisor serving as a reference object. In both retraction with tip and retraction with torque groups, the postulate bone traces tooth movement was not preserved and a bone remodeling/tooth movement ratio of 1:2 and 1:2.35 was obtained, respectively. In retraction with tip movement, the apical one third of the root tipped labially reducing the superior area of labial maxillaris by 19%. However, due to the compensating effect of the retraction movement, no apex approximation to the labial cortical plate occurred (eliminating the hazard of root resorption, dehiscence, or fenestration). In retraction with torque movement, the increase in both superior (28%) and inferior (65%) labial maxillaris areas was indicative for the hazard of root approximation to the palatal cortical bone. It is recommended to use the 1:2 bone remodeling/tooth movement ratio as a guideline to determine the biocompatible range of orthodontic tooth movements. Furthermore, a judicious interplay between the two modes of retraction can prevent major biologic impairments associated with the ratio and can extend the orthodontic range of treatment.
Direct and indirect resorption are perceived as reactions to an applied force. This is in contrast to the view of orthopedic surgeons, who describe apposition as a reaction to loading of bone. A histomorphometric study of the circumalveolar bone reaction to a force system generating translation of premolars and molars of five maccaca fascicularis monkeys is described. Three force levels (100 cN, 200 cN, and 300 cN) were applied for a period of 11 weeks. Undecalcified serial sections were cut parallel to the occlusal plane, and a grid consisting of three concentric outlines of the root intersected by six radii was placed on each section. Areas anticipated to be submitted to different stress/strain distributions were isolated. A-posteriori tests were used in order to separate areas that differed with regard to parameters reflecting bone turnover. Based on these results, a new hypothesis regarding tissue reaction to orthodontic forces is suggested. Direct resorption could be perceived as a result of the lowering of the normal strain from the functioning PDL and as such, as a start of remodeling, in the bone biological sense of the word. Indirect remodeling could be perceived as a sterile inflammation attempting to remove ischemic bone under the hyalinized tissue. At a distance from the alveolus, dense woven bone was observed as a sign of a RAP (regional acceleratory phenomena). The apposition could, according to the new hypothesis, be perceived as a result of the bending of the alveolar wall produced by the pull from the Sharpey fibers. The above suggested interpretation of tissue reaction would be shared with bone biologists.
The purpose of this study was to examine the prevalence, distribution, and features of alveolar dehiscences and fenestrations in modern American skulls and correlate their presence with occlusal attrition, root prominence, and alveolar bone thickness.
A representative sample of 146 dentate modern American skulls from a collection at the National Museum of Natural History were examined.
The skulls were from subjects ranging in age from 17 to 87 years old (mean 49.1 years). The mean number of teeth per skull was 22.7 and the mean number of either dehiscence or fenestration defects per skull was 3.0. Of the 3,315 individual teeth examined, 4.1% (135) had dehiscences and 9.0% (298) had fenestrations. A dehiscence was present in 40.4% of the skulls, and a fenestration was present in 61.6% of skulls. Mandibular canines were most often affected by dehiscences (12.9%), while maxillary first molars were most often affected by fenestrations (37.0%). Sixty-seven percent of dehiscences were found in the mandible, and 58% of fenestrations were found in the maxilla.
The presence of dehiscences and fenestrations were positively correlated with thin alveolar bone and negatively correlated with occlusal attrition. African-American males and Caucasian females were significantly more likely to have dehiscences, while African-American females were significantly more likely to have fenestrations.
In cases of bimaxillary protrusion, extraction of 4 premolars and orthodontic treatment with retraction of the anterior teeth is a widely used approach. However, there is controversy over whether the changes that occur in the anterior alveolar bone always follow the direction and quantity of tooth movement. Nineteen patients with dentoalveolar bimaxillary protrusion treated by extracting the 4 first premolars were evaluated with lateral cephalograms and computed tomography (CT). Cephalograms and CT scans were made before treatment and 3 months after retraction of the incisors. The measurements of the cephalograms showed that maxillary and mandibular incisors were retracted primarily by controlled tipping of the teeth. For all maxillary and mandibular incisors, we assessed the labial and the lingual alveolar plates at crest level (S1), midroot level (S2), and apical level (S3) for bone-thickness changes during retraction of the maxillary and mandibular anterior segments. In the mandibular arch, the labial bone maintained its original thickness, except the S1 measurements, which showed a significant decrease in bone thickness (P <.001). In the maxillary arch, the labial bone thickness remained unchanged. There were statistically significant decreases in lingual bone width in both arches after retracting the incisors. Some of the patients demonstrated bone dehiscence that was not visible macroscopically or cephalometrically. When tooth movement is limited, forcing the tooth against the cortical bone may cause adverse sequelae. This type of approach must be carefully monitored to avoid negative iatrogenic effects.
The purpose of this investigation was to measure the tissue-absorbed dose and to calculate the effective dose for the NewTom 9000, a new generation of computed tomographic devices designed specifically for dental applications. Comparisons are made with existing reports on dose measurement and effective dose estimates for panoramic examinations and other computed tomographic imaging modalities for dental implants.
Thermoluminescent dosimeters were implanted in a tissue-equivalent humanoid phantom at anatomic sites of interest. Absorbed dose measurements were obtained after single and double exposures. The averaged tissue-absorbed doses were used for the calculation of the whole-body effective dose.
The effective dose for imaging of maxillomandibular volume with a NewTom 9000 machine is 50.3 muSv.
The effective dose with the NewTom 9000 machine is significantly less than that achieved with other computed tomographic imaging methods and is within the range of traditional dental imaging modalities.
The aim of the present study was to determine the influence of gingival dimensions on the development of gingival recession following placement of artificial crowns. The study population consisted of 11 periodontally healthy patients in whom 44 maxillary anterior teeth and/or premolars had to be crowned. A total of 36 teeth (82%) had, after crown placement, a mean intracrevicular crown margin of 0.57 +/- 0.47 mm. Thirty-nine teeth without restorations served as controls. Immediately after incorporation, as well as after 3, 6, 9, and 12 months, periodontal examinations were carried out. Gingival thickness was determined sonometrically and averaged 1.25 +/- 0.40 mm. Mean periodontal probing depth was 1.80 +/- 0.54 mm. Twelve months later, crowned teeth had experienced a mean attachment loss of 0.17 +/- 0.99 mm as compared to an attachment gain of 0.18 +/- 0.46 mm at control teeth. At test teeth, the gingival margin had receded a mean of 0.43 +/- 0.74 mm. In multivariate analyses considering the correlated structure of the data employing generalized estimating equation methods, crown placement was identified as a major factor for attachment loss and development of gingival recession. In addition, a shallow probing depth and narrow band of gingiva negatively influenced the level of periodontal attachment. The present results point to the importance of a more detailed periodontal diagnosis of the dentogingival region before placement of artificial crowns.
The purpose of this study was to investigate the differences in initial skeletal, dental, and soft tissue characteristics of bimaxillary protrusion (BP) patients to determine poor or good results with orthodontic treatment (OT) or anterior segmental osteotomy (ASO) with extraction of four first premolars. Lateral cephalometric radiographs of 46 adult Korean females with BP were analyzed before treatment (T0) and after treatment (T1). According to the measurements at T1, patients were classified into group 1 (poor result with OT, n = 12), group 2 (good result with OT, n = 11), group 3 (poor result with ASO, n = 5), and group 4 (good result with ASO, n = 18). Sagittal, vertical, dental, and soft tissue variables were measured. The differences at T0 among the four groups were compared by one way analysis of variance test and verified by Scheffe's multiple comparison test. Stepwise discriminant analysis was performed to find decisive predictors. Skeletal class II malocclusion tendency, less developed chin, and vertical facial growth pattern were related with group 1. Overly uprighted and less protrusive upper and lower incisor, near normal interincisal angle (IIA), less protrusive upper lip, and more obtuse lower nasolabial angle (NLA) were related with group 3. IIA, U1-NA distance, combination factor, interlabial gap, lower NLA, pterygomaxillary fissure-N, and posterior nasal spine-anterior nasal spine were selected as significant variables for discriminating the four groups. The percentage of correctly classified cases was 91.3%. In particular, the discriminant function showed the highest accuracy in the prediction of group 4. These variables and discriminant functions contributed to the differential diagnosis on BP to make a procedural decision between OT and ASO.
Labial movement of mandibular incisors has traditionally been considered a risk factor for gingival recession. The aims of this study were to assess changes in prevalence and severity of gingival recession of mandibular incisors during orthodontic treatment of adults in whom the incisors had been moved labially and to identify parameters that could predict recession.
The sample consisted of 150 adult patients (aged 33.7 +/- 9.5 years, mean +/- SD) treated nonextraction with fixed appliances. Pretreatment overjet, overbite, degree of crowding, presence of tooth rotation, canine relationship, vertical face height, and position of the mandibular incisor to A-pogonion and mandibular lines were registered on study casts and lateral headfilms. Pretreatment gingival recession, width of keratinized gingiva, gingival biotype, gingival inflammation, and visible plaque accumulation were recorded, as was posttreatment gingival recession. Labial movement was determined by measuring pretreatment and posttreatment casts. Descriptive statistics were used to describe gingival recession at baseline and follow-up. Variables to be included in a logistic regression analysis as possible predictors of recession were identified with a bivariate correlation analysis.
No significant increase in the mean gingival recession was observed during treatment. The prevalence of gingival recession greater than 0.1 mm increased from 21% before treatment to 35% after (P < .05). Only 2.8% of the subjects developed recession greater than 2 mm, and 5% of the pre-existing gingival recessions improved. The presence of baseline recession (P < .001), gingival biotype (P < .0179), and gingival inflammation (P < .003) were identified as possible predictors of recession. None of the orthodontic variables was significantly associated with recession.
Gingival recession of mandibular incisors did not significantly increase during orthodontic treatment. After treatment, fewer than 10% of subjects had gingival recession greater than 2 mm, and, at follow-up, 5% of the pre-existing gingival recession had improved. Thin gingival biotype, visual plaque, and inflammation are useful predictors of gingival recession.
The aim of this study of native pig and human mandibles was to investigate the accuracy and quality of the representation of periodontal defects by intraoral radiography (IR), panoramic radiography (PR), computed tomography (CT), and digital volume tomography (DVT) in comparison with histologic specimens.
Following the standardized preparation of periodontal defects (14 dehiscences, fenestrations, 2- to 3-walled intrabony defects, respectively; Class I, II, and III furcation involvement) in six pig and seven human mandibles, IR, PR, CT, and DVT were performed. The histologic specimens were produced by cutting blocks with the individual defects out of the mandibles, embedding them in acrylic, and producing sagittal and axial microsections. The intrabony defects were measured using appropriate software on the digitized IR and PR images programs. The histologic sections were measured by reflecting stereomicroscopy. The statistical comparison between the measurements of the radiographic images and those of the histologic specimens was performed with Pearson's correlation coefficient. The quality of the radiographic images was determined through the subjective perception and detectability of the intrabony defects by five independent observers.
All intrabony defects could be measured in three planes in the CT and DVT scans. Comparison with the histologic specimens yielded a mean deviation of 0.16 +/- 0.10 mm for the CT scans and 0.19 +/- 0.11 mm for the DVT scans. On the IR and PR images, the defects could be detected only in the mesio-distal and craniocaudal planes. In comparison with the histologic specimens, the IR images revealed a mean deviation of 0.33 +/- 0.18 mm and the PR images a mean deviation of 1.07 +/- 0.62 mm. The quality rating of the radiographic images was highest for the DVT scans.
Overall, the CT and DVT scans displayed only a slight deviation in the extent of the periodontal defects in comparison with the histologic specimens. Both radiographic imaging techniques permitted imaging of anatomic osseous structures in three planes, true to scale, and without overlay or distortion. The DVT scans showed the best imaging quality.