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Association between nonextraction clear aligner therapy and alveolar bone dehiscences and fenestrations in adults with mild-to-moderate crowding
Abstract
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.
... Clear aligner Therapy can be used in patients of any age; however, it should be used with caution. Allahham, et al., reported that non-extraction treatment of mild to moderate crowding in adult patients with CAT led to an increased occurrence of Fenestrations and Dehiscence [10]. ...
Introduction: Clear aligners are emerging as a potential treatment option in the field of Orthodontics. General dentists are usually the first ones to determine the Orthodontic needs of the patient. With an increasing demand for aligners in daily practice; it is vital for dental students/ future practitioners to know about the basics of clear aligner therapy. Aim and Objectives: The aim of this study was to evaluate the knowledge, awareness and attitude regarding CAT among BDS Interns. Materials and Methods: A self-designed online questionnaire of 20 questions was designed and distributed among 378 BDS Interns via WhatsApp messenger and email. Results: The majority of participants were aware of the advantages of Clear Aligner Therapy over fixed appliances. However, most lacked knowledge regarding patient instructions, like wearing time, cleaning methods, etc. There was less awareness about the types of tooth movements possible with CAT, factors influencing tooth movement, associated auxiliaries, etc. Conclusion: It is important for general dentists to be aware of the various treatment modalities and the associated indications, pros, cons and patient instructions. Thus, there is need for addition of more details regarding advances like Aligners in the curriculum to improve the knowledge, awareness and attitude of emerging dentists.
... 2,3 Recently, Allahham et al. evaluated the cone-beam computed tomography (CBCT) images of adult patients with mild-to-moderate crowding treated with nonextraction clear aligner therapy and found an increase in alveolar bone dehiscence and fenestration from dental arch expansion. 4 Clinicians often assess alveolar bone anatomy of the anterior teeth by either subjective palpation or analyzing lateral cephalograms. With the broad adaption of threedimensional (3D) imaging in the dental field in the past decade, several clinicians/research groups have evaluated alveolar bone thickness in the mandibular incisor region on CBCT in the past few years and have consistently reported that hyperdivergent patients had a thin symphysis and a thin alveolus in the incisor region. ...
Objective
To evaluate the mandibular alveolar bone thickness in untreated skeletal Class I subjects with different vertical skeletal patterns.
Materials and Methods
A total of 50 preorthodontic treatment cone-beam computed tomography (CBCT) images of a skeletal Class I Chinese population with near-normal occlusion were selected. The buccal and lingual alveolar bone thicknesses of mandibular canines to second molars were measured at 2 mm below the cementoenamel junction (CEJ), mid-root, and root apex levels. Differences in the measurements were analyzed with Mann-Whitney U-test. The correlation between alveolar bone thickness and the sella-nasion–mandibular plane (SN-MP) angle was calculated using Pearson correlation coefficients and linear regression analysis.
Results
Buccal alveolar bone was thinner on all mandibular canines to first molars but thicker on second molars in comparison with lingual alveolar bone. Buccal alveolar bone was within 1 mm at the levels of 2 mm below CEJ and mid-root for the canines and first premolars. Significant differences were detected among subjects with different vertical patterns, with a negative correlation between the SN-MP angle and alveolar thickness, especially in the canine and premolar regions. The thinnest buccal and lingual alveolar bone were detected in the high-angle group canine region (0.50 mm at the levels of 2 mm below CEJ and mid-root for the buccal side, 0.90 mm at the level of 2 mm below the CEJ for the lingual side).
Conclusions
To avoid periodontal complications, buccal-lingual movement of the mandibular canines and first premolars should be limited, especially in high-angle patients.
... For root parallelism rate and bone dehiscence rate, no signi cant differences were found between CA and FA groups. While a study has indicated that non-extraction with CAs was associated with an increased presence of bone dehiscence [39]. These variations may arise from different treatment mechanics and forces applied. ...
Objective
This retrospective cohort study aims to compare the performance of clear aligners (CAs) with fixed appliances (FAs) in pre-surgical orthodontics of skeletal class III malocclusion patients.
Materials and Methods
Ninety-five patients were included in the study, and were divided into four groups: extraction with CA, extraction with FA, non-extraction with CA, and non-extraction with FA. The effectiveness of the treatments was measured using several parameters, including the PAR index, arch width coordination, incisor up-righting, root parallelism, root resorption, and bone dehiscence. The efficiency of the treatments was evaluated by comparing the duration of pre-surgical treatment and the number of follow-up visits.
Results
CAs were found to be as effective as FAs in the pre-surgical orthodontics of skeletal class III malocclusion. However, there are significant differences in treatment duration and follow-up visits between the two groups. The treatment duration was significantly shorter in CA groups than that in FA groups (409.21 ± 172.01 vs. 548.29 ± 208.14 days, P = 0.015 for non-extractions while 536.16 ± 195.78 vs. 768.32 ± 316.83 days, P = 0.009 for extractions). Similarly, the number of follow-up visits were statistically lower in the CA groups as well (7.58 ± 3.24 vs. 16.08 ± 5.28 visits, P = 0.001 for non-extractions, while 9.37 ± 3.73 vs. 22.39 ± 10.08 visits, P = 0.001 for extractions). Furthermore, the non-extraction with CA group showed better U1-SN reduction than the non-extraction with FA group (1.46 ± 5.57 VS -2.52 ± 6.11 degrees, P = 0.023).
Conclusions
CAs are an effective alternative to FAs for pre-surgical orthodontic treatment of skeletal class III malocclusion patients. Moreover, they offer high efficiency by shortening treatment duration and reducing the number of follow-up visits.
Clinical relevance
CAs can be a highly efficient and effective option in pre-surgical orthodontic of skeletal class III malocclusion.
Introduction
This study aimed to compare the extent of buccal bone defects (dehiscences and fenestrations) and transversal tooth movement of mandibular lateral segments in patients after orthodontic treatment with and without piezocision in cone-beam computed tomography and digital dental models.
Methods
The study sample of this study consisted of cone-beam computed tomography scans and digital dental models taken before (T0) and after (T1) orthodontic treatment of 36 patients with moderate mandibular anterior crowding. The experimental group consisted of 17 patients that had piezocision performed at the beginning of treatment with the goal of accelerating tooth movement, which was compared with 19 patients who did not receive piezocision. The measurement of bone defects, buccolingual inclination, and transversal distances of the tooth in the mandibular lateral segments (mandibular canines, premolars, and first molars) were evaluated at baseline and at the end of the orthodontic treatment.
Results
Overall, an increase in dehiscences, buccal inclination, and arch width from T0 to T1 was observed in both groups, but no statistically significant difference was found between groups. A significant increase in fenestrations from T0 to T1 was observed only for the canines in the experimental group. No statistically significant association was found between the increase of dehiscences and the amount of buccolingual inclination or transversal width changes. However, the changes in transversal width were statistically significantly associated with the increase in buccal inclination at the canines, first and second premolars.
Conclusions
No significant differences were found in buccal dehiscences and transversal tooth movement (buccolingual inclination and arch width) of mandibular lateral segments between patients after orthodontic treatment with and without piezocision. Dehiscences, buccal inclination, and arch width significantly increased from T0 to T1 in both groups.
Background: The presence of dentoalveolar lesions such as fenestration and dehiscence has great clinical importance. This study was designed to determine the incidence of bony fenestrations and dehiscences associated with the anterior teeth by using cone-beam computed tomography images.
Materials and Methods: A total of 216 images (1189 teeth) were included in this cross-sectional study. The presence of fenestration and dehiscence at the buccal and lingual/palatal surfaces and also their relative levels on the roots of the teeth were determined. McNemar's, Chi-square, and Cochran's Q tests were used for data analysis. A value of P < 0.05 was considered to be statistically significant.
Results: The incidence of fenestration and dehiscence was 17.6% and 3.9%, respectively with the maxillary fenestrations being more prevalent (P < 0.0001). No significant differences were observed in the incidence of dehiscences between the jaws (P = 0.824) and among the tooth types (P = 0.689). The lesions were more frequent at the buccal surfaces (80%–92.5%). About 85.9% of the fenestrations occurred in the apical root thirds, whereas dehiscences had the highest prevalence in the cervical thirds. Fenestration and dehiscence incidences were significantly higher in females (P < 0.05). There was no significant difference among the age groups regarding these lesions.
Conclusion: Fenestration and dehiscence were observed more on the buccal surfaces and also in the apical and cervical root thirds, respectively. Age had no significant influence on the occurrence of these lesions in contrast to the sex.
Background
To evaluate the changes of alveolar dehiscence and fenestration after augmented corticotomy-assisted orthodontic treatment on cone-beam computed tomography (CBCT) compared with traditional pre-surgical orthodontics, both quantitatively and qualitatively.
Methods
Two hundred and four anterior teeth from 17 skeletal class III malocclusions were divided into four groups. Groups G1 (upper teeth) and G3 (lower teeth), comprising 120 teeth, accepted traditional pre-surgical orthodontics; groups G2 (upper teeth) and G4(lower teeth), comprising 84 teeth, accepted augmented corticotomy-assisted pre-surgical orthodontics. The changes of alveolar bone dehiscence and fenestration of each tooth in all groups were evaluated with the help of CBCT.
Results
Quantitative analysis for comparing both groups: For the upper teeth, d1 − d0 was different between both groups while f1 − f0 was not statistically different. For the lower teeth, d1 − d0 was statistically different between both groups while f1 − f0 was not statistically different. Qualitative analysis: For the teeth that had no dehiscence before treatment, G2 and G4 had a better transition than did G1 and G3. For those having dehiscence before treatment, G4 had a better transition than did G3. For teeth having no fenestration before treatment, there was no statistically significant difference in transition between the control and treatment groups. For those having fenestration before treatment, G4 had a better transition than did G3.
Conclusions
For skeletal class III patients, augmented corticotomy-assisted orthodontic treatment is a promising method of improving alveolar bone dehiscence and fenestration for lower anterior teeth, and it also has the potential to protect both lower and upper anterior teeth against dehiscence.
Background
Align technology has developed greatly over past few years. Patients tended to prefer clear aligners over conventional brackets because of the superior comfort and esthetics, while the effectiveness of clear aligners was still controversial. The aim of this systematic review was to verify whether the treatment effectiveness of clear aligners was similar to the conventional fixed appliances.
Methods
A comprehensive search of the Pubmed, Web of Science, Embase, Scopus, and Cochrane Central Register of Controlled Clinical Trials Register databases for studies published through to August 20, 2018 was conducted. Comparative clinical studies assessing the effectiveness of clear aligners compared with braces were included.
Results
Eight papers were included in this study. Two of the included papers were randomized controlled trials and six were cohort studies. Clear aligners might not be as effective as braces in producing adequate occlusal contacts, controlling teeth torque, increasing transverse width and retention. While no statistically significant difference was found between two groups in Objective Grading System score (WMD = 8.38, 95% CI [− 0.17, 16.93]; P = 0.05). On the other hand, patients treated with clear aligners had a statistically significant shorter treatment duration than with braces (WMD = − 6.31, 95% CI [− 8.37, − 4.24]; P < 0.001).
Conclusion
Both clear aligners and braces were effective in treating malocclusion. Clear aligners had advantage in segmented movement of teeth and shortened treatment duration, but were not as effective as braces in producing adequate occlusal contacts, controlling teeth torque, and retention.
The aim of this study was to introduce an improved surgical technique using a pouch design and tension-free wound closure for periodontally accelerated osteogenic orthodontics (PAOO) in the anterior alveolar region of the mandible.
Patients with bone dehiscence and fenestrations on the buccal surfaces of the anterior mandible region underwent the modified PAOO technique (using a pouch design and tension-free closure). Postoperative symptoms were evaluated at 1 and 2 weeks intervals following the procedure. Probing depth (PD), gingival recession depth (GRD), and clinical attachment level (CAL) were assessed at the gingival recession sites at baseline, postoperative 6 and 12 months. Cone-beam computerized tomography (CBCT) was used for quantitative radiographic analyses at baseline, 1 week and 12 months after bone-augmentation procedure.
The sample was composed of a total of 12 patients (2 males and 10 females; mean age, 21.9 years) with 72 teeth showing dehiscence/fenestrations and 17 sites presenting with gingival recessions. Clinical evaluations revealed a statistically significant reduction in swelling, pain, and clinical appearance from postoperative week 1 to week 2 (P < .05). Moreover, gingival recession sites exhibited a significant reduction in the GRD and an increase in CAL after surgery with mean root coverage of 69.8% at the end of observation period (P < .01). Both alveolar bone height and width increased after surgery (P < .01) and decreased during the 12-month follow-up (P < .01). However, compared with the baseline records, there was still a significant increase in alveolar bone volume (P < .01).
This modified PAOO technique may have advantages in terms of soft and hard tissue augmentation, facilitating extensive bone augmentation and allowing the simultaneous correction of vertical and horizontal defects in the labial aspect of the mandibular anterior area.
The aim of this study was to evaluate the effects of the mandibular protraction appliance (MPA) for treating mild to moderate Class II malocclusion at different stages of dentofacial development. Lateral radiographs were evaluated before (T0) and at the end (T1) of orthodontic treatment with fixed appliance associated with MPA. Sixty-five consecutively treated patients were divided according to the stage of dentofacial development: 21 children in late mixed dentition, 22 adolescents and 22 young adults with full permanent dentition. The differences between and within groups were analyzed by MANOVA at p<0.05. The correction of anteroposterior discrepancy (Wits) was significantly reduced in all development stages (p<0.01), with no difference between groups. Class II was corrected predominantly by dental changes in the mandibular arch, with accentuated proclination of the mandibular incisors and mesial displacement of mandibular molars. The MPA had no skeletal effects in any of the groups, except for a mild reduction of SNA (p=0.018) and ANB angles (p<0.0001) among the mixed dentition children. With regard to soft-tissue profile, facial convexity decreased significantly in all groups (p<0.01). In conclusion, the MPA associated with fixed appliance corrected the Class II occlusion, basically by a mandibular arch protrusion. A mild skeletal maxillary change was significant only when this treatment protocol began during mixed dentition.
Forensic odontology plays a vital role in the identification and age estimation of unknown deceased individuals. The purpose of this study is to estimate the chronological age from Cone-Beam Computed Tomography (CBCT) images by measuring the buccal alveolar bone level (ABL) to the cemento-enamel junction and to investigate the possibility of employing the age-related structural changes of teeth as studied by Gustafson. In addition, this study will determine the forensic reliability of employing CBCT images as a technique for dental age estimation. A total of 284 CBCT images of Malays and Chinese patients (150 females and 134 males), aged from 20 years and above were selected, measured and stages of age-related changes were recorded using the i-CAT Vision software. Lower first premolars of both left and right side of the jaw were chosen and the characteristics described by Gustafson, namely attrition, secondary dentine formation and periodontal recession were evaluated. Linear regression analysis was performed for the buccal bone level and the R values obtained were 0.85 and 0.82 for left and right side respectively. Gustafson's characteristics were analysed using multiple regression analysis with chronological age as the dependent variable. The results of the analysis showed R values ranged from 0.44 to 0.62. Therefore it can be safely concluded that the buccal bone level highly correlated with the chronological age and is consequently the most suitable age-related characteristic for forensic age estimation.
Gingival recession has direct causes and predisposing factors. Orthodontic treatment is able to prevent recession and even contribute to its treatment, with or without periodontal approach, depending on the type and severity of gingival tissue damage. There is no evidence on the fact that orthodontic treatment alone might induce gingival recession, although it might lead the affected teeth (usually mandibular incisors or maxillary canines) to be involved in situations that act as predisposing factors, allowing direct causes to act and, therefore, trigger recession, especially when the buccal bone plate is very thin or presents with dehiscence. Several aspects regarding the relationship between orthodontic treatment and gingival recession have been addressed, and so has the importance of the periosteum to the mechanism of gingival recession formation. Clinical as well as experimental trials on the subject would help to clarify this matter, of which understanding is not very deep in the related literature.
Objectives:
To investigate the predictability of arch expansion using Invisalign.
Materials and methods:
Sixty-four adult white patients were selected to be part of this retrospective study. Pre- and posttreatment digital models created from an iTero scan were obtained from a single orthodontist practitioner. Digital models from Clincheck were also obtained from Align Technology. Linear values of upper and lower arch widths were measured for canines, premolars, and first molars at two different points: lingual gingival margins and cusp tips. A paired t-test was used to compare expansion planned on Clincheck with the posttreatment measurements. Variance ratio tests were used to determine if a larger change planned was associated with larger error.
Results:
For every maxillary measurement, there was a statistically significant difference between Clincheck and final outcome (P < .05), with prediction worsening toward the posterior region of the arch. For the lower arch measurements at the gingival margin, there was a statistically significant difference between the Clincheck planned expansion and the final outcome (P < .05). Points measured at the cusp tips of the lower arch teeth showed nonstatistically significant differences between Clincheck prediction and the final outcome (P > .05). Variance ratios for upper and lower arches were significant (P < .05).
Conclusions:
The mean accuracy of expansion planned with Invisalign for the maxilla was 72.8%. The lower arch presented an overall accuracy of 87.7%. Clincheck overestimates expansion by body movement; more tipping is observed. Overcorrection of expansion in the posterior region of the maxillary arch seems appropriate.
Few studies involving human participants have been conducted to investigate the effect of orthodontic treatment on alveolar bone density around the teeth. Our previous study revealed that patients who received 6 months of active orthodontic treatment exhibited an ∼24% decrease in alveolar bone density around the teeth. However, after an extensive retention period following orthodontic treatment, whether the bone density around the teeth can recover to its original state from before the treatment remains unclear, thus warranting further investigation.
The purpose of this study was to assess the bone density changes around the teeth before, during, and after orthodontic treatment.
Dental cone-beam computed tomography (CBCT) was used to measure the changes in bone density around 6 teeth in the anterior maxilla (maxilla central incisors, lateral incisors, and canines) of 8 patients before and after orthodontic treatment. Each patient underwent 3 dental CBCT scans: before treatment (T0); at the end of 7 months of active orthodontic treatment (T1); after several months (20–22 months) of retention (T2). The Friedman test was applied to evaluate the changes in the alveolar bone density around the teeth according to the 3 dental CBCT scans.
From T0 to T1, a significant reduction in bone density was observed around the teeth (23.36 ± 10.33%); by contrast, a significant increase was observed from T1 to T2 (31.81 ± 23.80%). From the perspective of the overall orthodontic treatment, comparing the T0 and T2 scans revealed that the bone density around the teeth was relatively constant (a reduction of only 0.75 ± 19.85%). The results of the statistical test also confirmed that the difference in bone density between T0 and T2 was nonsignificant.
During orthodontic tooth movement, the alveolar bone density around the teeth was reduced. However, after a period of bone recovery, the reduced bone density recovered to its previous state from before the orthodontic treatment. However, the bone density around ∼10% of the teeth in this region could not recover to 80% of its state from before the orthodontic treatment.
Objective:
To assess the scientific evidence related to the efficacy of clear aligner treatment (CAT) in controlling orthodontic tooth movement.
Materials and methods:
PubMed, PMC, NLM, Embase, Cochrane Central Register of Controlled Clinical Trials, Web of Knowledge, Scopus, Google Scholar, and LILACs were searched from January 2000 to June 2014 to identify all peer-reviewed articles potentially relevant to the review. Methodological shortcomings were highlighted and the quality of the studies was ranked using the Cochrane Tool for Risk of Bias Assessment.
Results:
Eleven relevant articles were selected (two Randomized Clinical Trials (RCT), five prospective non-randomized, four retrospective non-randomized), and the risk of bias was moderate for six studies and unclear for the others. The amount of mean intrusion reported was 0.72 mm. Extrusion was the most difficult movement to control (30% of accuracy), followed by rotation. Upper molar distalization revealed the highest predictability (88%) when a bodily movement of at least 1.5 mm was prescribed. A decrease of the Little's Index (mandibular arch: 5 mm; maxillary arch: 4 mm) was observed in aligning arches.
Conclusions:
CAT aligns and levels the arches; it is effective in controlling anterior intrusion but not anterior extrusion; it is effective in controlling posterior buccolingual inclination but not anterior buccolingual inclination; it is effective in controlling upper molar bodily movements of about 1.5 mm; and it is not effective in controlling rotation of rounded teeth in particular. However, the results of this review should be interpreted with caution because of the number, quality, and heterogeneity of the studies.
To evaluate the changes in cortical bone thickness, alveolar bone height, and the incidence of dehiscence and fenestration in the surrounding alveolar bone of posterior teeth after rapid maxillary expansion (RME) treatment using cone-beam computed tomography (CBCT).
The CBCT records of 20 subjects (9 boys, mean age: 13.97 ± 1.17 years; 11 girls, mean age: 13.53 ± 2.12 year) that underwent RME were selected from the archives. CBCT scans had been taken before (T1) and after (T2) the RME. Moreover, 10 of the subjects had 6-month retention (T3) records. We used the CBCT data to evaluate the buccal and palatal aspects of the canines, first and second premolars, and the first molars at 3 vertical levels. The cortical bone thickness and alveolar bone height at T1 and T2 were evaluated with the paired-samples t-test or the Wilcoxon signed-rank test. Repeated measure ANOVA or the Friedman test was used to evaluate the statistical significance at T1, T2, and T3. Statistical significance was set at p < 0.05.
The buccal cortical bone thickness decreased gradually from baseline to the end of the retention period. After expansion, the buccal alveolar bone height was reduced significantly; however, this change was not statistically significant after the 6-month retention period. During the course of the treatment, the incidence of dehiscence and fenestration increased and decreased, respectively.
RME may have detrimental effects on the supporting alveolar bone, since the thickness and height of the buccal alveolar bone decreased during the retention period.
The present adult patient case report shows the correction of a crossbite malocclusion and severe tooth rotations treated with the Invisalign system.
A 27-year-old female with a dental crossbite (24, 34), severe rotations of two lower incisors (more than 40 degrees) and malalignment of the upper and lower arches is described. The Invisalign system was treatment planned to correct the malocclusion.
The treatment goals of crossbite, rotation and malalignment correction were achieved after 12 months of active aligner therapy. The overbite improved (2.5 mm before treatment, 1 mm at the end); the dental crossbite, the crowding and the severe tooth rotations (with a mean of 2 degrees of improvement per aligner) were corrected.
After treatment, the dental alignment was considered excellent. The presented case indicates that the Invisalign system can be a useful appliance to correct a dental malocclusion involving severe rotations.
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.
Demineralization of a thin layer of bone over a root prominence after corticotomy surgery can optimize the response to applied orthodontic forces. This physiologic response is consistent with the regional acceleratory phenomenon process. When combined with alveolar augmentation, one is no longer strictly at the mercy of the original alveolar volume and osseous dehiscences, and fenestrations can be corrected over vital root surfaces. This is substantiated with computerized tomographic and histologic evaluations. Two case reports are presented that demonstrate the usefulness of the accelerated osteogenic orthodontics technique in de-crowding and space closing for the correction of dental malocclusions.
Orthodontics is combined with full-thickness flap reflection, selective alveolar decortication, ostectomy, and bone grafting to accomplish complete orthodontic treatment.
Rapid tooth movement was demonstrated in both cases and stability up to 8 years of retention.
The accelerated osteogenic orthodontics technique provides for efficient and stable orthodontic tooth movement. Frequently, the teeth can be moved further in one third to one fourth the time required for traditional orthodontics alone. This is a physiologically based treatment consistent with a regional acceleratory phenomenon and maintaining an adequate blood supply is essential.
The periodontal attachment apparatus consists of the periodontal ligament, alveolar bone, cementum and supra-crestal connective tissue. They are interdependent and provide protection and support to the dentition. It is theorized that the integrity of the periodontal apparatus can be maintained throughout life by exercising comprehensive oral hygiene practices and routine dental care. Additionally, it appears to be unaffected by aging. As a consequence, the investigators performed a study to determine the effects of chronological aging on alveolar bone loss.
The present study was conducted to determine the relationship between oral alveolar bone loss, oral hygiene, and aging among African-American and Caucasian populations.
The population consisted of 229 individuals. There were 131 men and 98 women. With respect to race there were 89 African-Americans and 140 Caucasians. Oral examinations, oral hygiene and missing teeth determinations and bitewing radiographs were performed on all the individuals. Radiographs were digitized and measurements were made from the cementum/enamel junction to the alveolar bone crest. Measurements were made for both the maxillary and mandibular jaws.
The results of the study showed a significant multiple linear regression model relationship between oral bone loss and aging. Oral hygiene was a factor, but contributed only slightly to the overall model. Race, gender and the number of missing teeth were not significant variables in the overall model.
The results of this study suggest age-related alveolar bone loss.
Objectives
To evaluate the morphometric changes in maxillary and mandibular anterior alveolar bone after orthodontic treatment and retention for 18-24 months by cone-beam computed tomography (CBCT).
Setting and Sample Population
Thirty-four adolescent patients (12 males and 22 females; mean age: 14.29±1.24 years) diagnosed with bimaxillary dentoalveolar protrusion and with extractions of the 4 first premolars were included.
Materials and Methods
The labial and lingual (palatal) alveolar bone thickness, height and root length of the maxillary and mandibular anterior teeth were assessed using CBCT imaging at the pre-treatment (T1), post-treatment (T2) and retention phases (T3). Voxel-based superimpositions of the T2 and T3 images were performed and the distances of incisal and apical movement between T2 and T3 were measured to determine whether relapses occurred.
Results
After orthodontic treatment, the labial and lingual (palatal) bone height decreased significantly (p < 0.005) and the labial thickness at the crestal (L1), midroot (L2), and apical levels (L3) had no significant change, while the lingual (palatal) bone thickness at all three levels decreased significantly (p < 0.005). After 18-24 months of retention, the lingual (palatal) height and the lingual (palatal) thickness at the crestal (L1) level increased significantly (p < 0.005). There were no obvious incisal and apical movement of the anterior teeth between T2 and T3 (p>0.05), indicating that no relapses occurred.
Conclusions
Even though lingual (palatal) alveolar loss occurred due to the orthodontic treatment, the cervical alveolar bone seemed to recover over time. Therefore, appropriate camouflage treatments can be used in patients with bimaxillary dentoalveolar protrusion, and this treatment will not irreversibly deteriorate periodontal health and affect the orthodontic treatment stability.
Objectives
To evaluate the accuracy of integrated models (IMs) constructed by pretreatment cone-beam computed tomography (pre-CBCT) in diagnosing alveolar defects after treatment with clear aligners.
Materials and Methods
Pre-CBCT and posttreatment cone-beam computed tomography (CBCT) scans from 69 patients who completed nonextraction treatment with clear aligners were collected. The IMs comprised anterior teeth in predicted positions and alveolar bone from pre-CBCT scans. The accuracy of the IMs for identifying dehiscences or fenestrations was evaluated by comparing the means of the defect volumes, absolute mean differences, and Pearson correlation coefficients with those measured from post-CBCT scans. Defect prediction accuracy was assessed by sensitivity, specificity, positive predictive values, and negative predictive values. Factors possibly affecting changes in mandibular alveolar defects were analyzed using a mixed linear model.
Results
The IM measurements showed mean deviations of 2.82 ± 9.99 mm3 for fenestrations and 3.67 ± 9.93 mm3 for dehiscences. The absolute mean differences were 4.50 ± 9.35 mm3 for fenestrations and 5.17 ± 9.24 mm3 for dehiscences. The specificities of the IMs were higher than 0.8, whereas the sensitivities were both lower (fenestration = 0.41; dehiscence = 0.53). The positive predictive values were unacceptable (fenestration = 0.52; dehiscence = 0.62), and the overall reliability was low (<0.80). Molar distalization and proclination were positively correlated with significant increases in alveolar defects at the mandibular incisors after treatment.
Conclusions
Alveolar defects after clear aligner treatment cannot be simulated accurately by IMs constructed from pre-CBCT. Caution should be taken in the treatment of crowding with proclination and molar distalization for the safety of alveolar bone at the mandibular incisors.
INTRODUCTION:
Implant osseointegration is strongly influenced by the bone quality at the implant insertion site. The present work aims to create distribution diagrams showing the average bone density at each position within the jaws.
MATERIALS AND METHODS:
Data were retrospectively collected from 4 oral surgeons who sought bone-density measurements during implant placement using a torque-measuring implant micromotor. Statistical analyses were performed to investigate whether bone density correlated with the patients' sex and age and whether the bone-density values at different positions within each arch correlated to each other.
RESULTS:
Records of 2408 patients and 6060 bone-density readings were retrieved, and density distribution diagrams were created. Density values showed a significant variation within subjects. Within the same jaw, density between adjacent positions showed significant differences. Density at a given position correlated significantly with that at the other positions in most cases. Bone density was significantly lower in women than in men; no significant correlation was found between bone density and the patient age.
CONCLUSIONS:
Bone density of patients displays significant interindividual variation, thus meaningful assessment must be conducted on a patient-by-patient basis.
Background:
Evidence exists on the clinical efficacy and safety of periodontally accelerated osteogenic orthodontics (PAOO) with "Piezocision"-a minimally invasive, flapless alternative to corticotomy for alveolar bone augmentation. Allograft has been extensively studied for alveolar bone augmentation in Piezocision; however, the use of deproteinized bovine bone mineral with 10% collagen (DBBM-C) in Piezocision for PAOO has not been investigated.
Methods:
This study is a prospective, observational, cohort study of 19 patients of Angle Class I malocclusion with a total of 692 teeth assessed for maintenance of health of the periodontal attachment apparatus. Patient-centered pain, sensitivity, and satisfaction outcomes, digital photographs and radiographs, and changes in probing depth, clinical attachment level, width of keratinized tissue, percussion sensitivity, pulp vitality tests, radiographic pathology, and root-crown-ratio were all recorded.
Results:
Overall treatment was significantly faster (5 to 7 days between clear aligner tray changes), periodontal parameters remained stable, and alveolar bone loss was not observed. Visual analog score for healing, sensitivity/duration, bleeding/duration, swelling/duration, appearance, and inflammation, demonstrated no significant differences between DBBM-C and control (no bone graft) groups. Patient-centered outcomes revealed high levels of satisfaction with Piezocision. Piezocision-treated teeth with DBBM-C tended to exhibit less root resorption, although it was not statistically significant (P = 0.074).
Conclusions:
Within the limits of the study, our results show that the use of DBBM-C with piezosurgically enhanced orthodontics is effective and safe. This study was not designed to demonstrate equivalence with other materials that might be used in Piezocision. To understand whether there is an advantage to using DBBM-C, additional studies may be required.
Background:
To calculate the prevalence of dehiscences and fenestrations and measure the buccal alveolar bone width overlying healthy mandibular incisors and canines.
Methods:
Cone Beam Computerized Tomographies (CBCTs) from patients aged 18 to 30 years were selected from a private database. The thickness of buccal bone in the sagittal scan was measured perpendicular to the long axis of 6 teeth at two locations: at the crest level and at the mid-root level. A single calibrated examiner performed all measurements. Descriptive and inferential statistics were performed.
Results:
A total of 100 CBCTs (600 teeth) were selected for the analysis. The overall prevalence of dehiscences and fenestrations was 89.16% and 5.16%, respectively. Dehiscences and fenestrations were shown to have a mean length of 6.78 ± 1.90 mm and 4.89 ± 1.74 mm, respectively. This result was similar between young and old subjects as well as between men and women. Bone width at the crest level was significantly thinner in women (0.71 ± 0.13mm), whereas men were found to have a statistically significant thicker bone at the mid-root level of tooth #33. Comparisons of bone width at the mid-root level among the 6 analyzed teeth showed no statistical difference.
Conclusions:
A high prevalence of dehiscences and sites with thin buccal bone were identified in correspondence of the lower anterior teeth by means of CBCT analysis.
Objectives:
The aim of this systematic review with meta-analysis was to assess the accuracy and reproducibility of dental measurements obtained from digital study models generated from cone beam computed tomography (CBCT) compared with those acquired from plaster models.
Methods:
Electronic databases Cochrane Library, Medline (via PubMed), Scopus, VHL, Web of Science, and System for Information on Grey Literature in Europe (SIGLE) were screened to identify papers from 1998 until February 2016. The inclusion criteria were: prospective and retrospective clinical trials in humans; validation and/or comparison articles of dental study models obtained from CBCT and plaster models, as well as articles that used dental linear measurements as an assessment tool. The methodological quality of the studies was carried out by QUADAS-2 tool. A meta-analysis was performed to validate all comparative measurements.
Results:
The databases search identified a total of 3160 items and 554 duplicates were excluded. After reading titles and abstracts 12 articles were selected. Five articles were included after reading in full. The methodological quality obtained through QUADAS-2 was poor to moderate. In the meta-analysis, there were statistical differences between the mesiodistal widths of mandibular incisors, maxillary canines and premolars, and overall Bolton analysis. Therefore, the measurements considered accurate were maxillary and mandibular crowding, intermolar width and mesiodistal width of maxillary incisors, mandibular canines and premolars, and in both arches for molars.
Conclusions:
Digital models obtained from CBCT were not accurate for all measures assessed. The differences were clinically acceptable for all dental linear measurements, except for maxillary arch perimeter. Digital models are reproducible for all measurements when intraexaminer assessment is considered and need improvement in interexaminer evaluation.
Since the introduction of the Tooth Positioner (TP Orthodontics) in 1944, removable appliances analogous to clear aligners have been employed for mild to moderate orthodontic tooth movements. Clear aligner therapy has been a part of orthodontic practice for decades, but has, particularly since the introduction of Invisalign appliances (Align Technology) in 1998, become an increasingly common addition to the orthodontic armamentarium. An internet search reveals at least 27 different clear aligner products currently on offer for orthodontic treatment. The present paper will highlight the increasing popularity of clear aligner appliances, as well as the clinical scope and the limitations of aligner therapy in general. Further, the paper will outline the differences between the various types of clear aligner products currently available.
The Clear Aligner can be used to correct tooth movement without involving extraction, surgery, and other adjunct orthopaedic appliances. Some forms ofattachments are required with clear aligners to achieve all major types of orthodontic tooth movements. The Clear Aligner is a procedure that can be performed by a clinician with computer simulation/calculation. Since the Clear Aligner can be fabricated in steps, it is readily available to change the treatment sequence throughout the course of the treatment in cases of complex malocclusions. The patient can receive any necessary dental procedures with ease during the course of the treatment. The treatment can also be easily resumed even if the patient has not worn the aligners for a period of time. The purpose of this article is to report dental anterior crossbite correction with a series of Clear Aligners without the use of any forms of attachments. The Clear Aligner could be used as an alternative in appropriate cases for those who are reluctant with conventional appliances.
To investigate the alveolar bone defects of anterior alveolar bone in patients with bimaxillary protrusion by using cone-beam computed tomography (CBCT).
The samples consisted of 50 patients with bimaxillary protrusion, who were assigned to the teenage group[20 cases, ( 13.1±1.0) years] and adult group[30 cases, (22.9±4.2) years] . The adult group included 9 hypo-divergent, 11 normo-divergent and 10 hyper-divergent patients. The images were obtained by using NewTom VG CBCT and the alveolar defects were evaluated.
The ratio of the patients had alveolar bone defects was 94.00%. Meanwhile, the defects were associated with 38.60% of all the teeth. Most defects occurred on labial alveolar bone (98.66%); fenestration was found more in the maxillary alveolar region and dehiscence occurred more in the mandible. The dehiscences (3.06%) and defects prevalence (30.13%) of the teenage group were significant lower than those of the adult group (11.73% vs. 42.46%), P<0.05; while there was no significance of the fenestrations prevalence between the two group (P>0.05). The hypo-divergent group had lower fenestrations prevalence (22.22%) than the normo-divergent (33.84%) and hyper-divergent groups (37.50%), P<0.05. The upper central incisor had the lowest alveolar bone defect prevalence.
Alveolar bone defects are common findings in patients with bimaxillary protrusion before orthodontic treatment. The prevalence of defects is affected by age and vertical-growth type.
The purposes of this study were to evaluate the accuracy of cone-beam computed tomography (CBCT) for detecting naturally occurring alveolar bone dehiscences and fenestrations and to find a better method to diagnose them.
The sample consisted of 122 anterior teeth in 14 patients with Class III malocclusion who accepted accelerated osteogenic orthodontic surgery in the anterior tooth region. Dehiscences and fenestrations were measured both directly, with a gauge during surgery, and indirectly, by CBCT scans collected before treatment. A Bland-Altman plot for calculating agreement between the 2 methods was used. Direct data were regarded as the gold standard, and indirect data were analyzed to evaluate the accuracy of CBCT for detecting dehiscences and fenestrations by sensitivity, specificity, positive predictive value, negative predictive value, Youden index, positive likelihood ratio, and negative likelihood ratio. Receiver operator characteristic curves were also used to determine the area under curve and the best critical points of CBCT for detecting dehiscences and fenestrations.
Both the sensitivity and specificity of CBCT for dehiscences and fenestrations were over 0.7. The negative predictive values were high (dehiscence, 0.82; fenestration, 0.98), whereas the positive predictive values were relatively low (dehiscence, 0.75; fenestration, 0.16). Areas under the curve were 0.873 for dehiscences and 0.766 for fenestrations. The best critical points for detecting both dehiscences and fenestrations were 2.2 mm.
Our study showed that the CBCT method has some diagnostic value for detecting naturally occurring alveolar bone dehiscences and fenestrations. However, this method might overestimate the actual measurements.
Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.
To investigate the prevalence and distribution of alveolar bone dehiscence and fenestration in anterior region of skeletal Class iii malocclusions.
The sample consisted of 19 males and 25 females with skeletal Class iii malocclusions selected from consecutive patients of Department of Oral and Cranio maxillofacial Science from May 1st to June 1st, 2012. Five hundred and twenty-three teeth were examined by cone-beam CT (CBCT) in total while alveolar bone dehiscences and fenestrations were detected and measured using a new method. The data was processed using SAS8.02 software package.
The prevalence of dehiscence was 61.57% in all teeth, while fenestration was 31.93% and the prevalence of defect (dehiscence or fenestration) was 77.44%. More defects were found in the mandible (58.52%) especially. The tooth site which was most commonly affected was lower canine, while the least was upper central incisor. No significant difference was found between both genders on most tooth sites of anterior region but more defects was found in lower central incisor and lower lateral incisor in male subjects.
Alveolar defect is an extremely common finding in this sample. Whether alveolar defects such as dehiscence and fenestration are potential factors of root resorption and addition bone loss is still unclear, and further researches are needed. Supported by National Natural Science Foundation of China (10972142), Research Fund of Science and Technology Commission of Shanghai Municipality (08411961600) and Program for Innovative Research Team of Shanghai Municipal Education Commission.
The reasons for inaccuracies in alveolar bone measurement from cone-beam computed tomography (CBCT) images might be multifactorial. In this study, we investigated the impact of software, the presence or absence of soft tissues, the voxel size of the scan, and the regions in the jaws on buccal alveolar bone height measurements in pigs at an age equivalent to human adolescents.
Marker holes, apical to the maxillary and mandibular molar roots, and mesiodistal molar occlusal reference grooves were created in 6 fresh pig heads (12 for each jaw), followed by CBCT scans at 0.4-mm and 0.2-mm voxel sizes under soft-tissue presence and soft-tissue absence conditions. Subsequently, buccolingual sections bisecting the marker holes were cut, from which the physical alveolar bone height and thickness were measured. One blinded rater, using Dolphin (version 11.5 Premium; Dolphin Imaging, Chatsworth, Calif) and OsiriX (version 3.9; www.osirix-viewer.com) software, independently collected alveolar bone height measurements from the CBCT images. Differences between the CBCT and the physical measurements were calculated. The mean differences and the limit of agreement (LOA, ±1.96 SD) for every jaw, voxel-size, soft-tissue, and software condition were depicted. Each measurement was then assessed for clinical inaccuracy by using 2 levels of criteria (absolute differences between CBCT and physical measurements ≥1 mm, or absolute differences between CBCT and physical measurements ≥0.5 mm), and the interactions between soft-tissue and voxel-size factors for every jaw and software condition were assessed by chi-square tests.
Overall, the mean differences between the CBCT and the physical measurements for every jaw, voxel-size, soft-tissue, and software condition were near 0. With all other conditions kept equal, the accuracy of the maxillary CBCT measurements was inferior (larger limit of agreement ranges and higher frequencies of clinical inaccuracy) to the mandibular measurements. The physical thickness of the maxillary alveolar crestal bone was less than 1 mm and significantly thinner than the mandibular counterparts. For every jaw and software condition, the accuracy of measurements from the 0.2-mm soft-tissue presence CBCT images was consistently superior (smaller limit of agreement ranges and lower frequencies of clinical inaccuracy) to those from the 0.4-mm soft-tissue presence, the 0.4-mm soft-tissue absence, and the 0.2-mm soft-tissue absence images; all showed similar accuracies. Qualitatively, the soft-tissue absence images demonstrated much brighter enamel and alveolar bone surface contours than did the soft-tissue presence images.
At an adolescent age, the buccal alveolar bone height measured from the maxillary molar region based on 0.4-mm voxel-size CBCT images can have relatively large and frequently inaccurate measurements, possibly due to its thinness. By using 0.2-mm voxel-size scans, measurement accuracy might be improved, but only when the overlying facial and gingival tissues are kept intact.
Background:
The width of the facial alveolar bone wall is crucial for long-term successful esthetic outcomes of implants immediately placed into extraction sockets. A threshold of 2 mm is recommended to minimize buccal vertical bone resorption.
Aim:
To assess the width of the facial alveolar bone wall using cone-beam computed tomography images (CBCT).
Material and methods:
Retrospective CBCT images were acquired from a representative sample of Asians using the i-CAT classic system with a 0.4-mm voxel size. At random, 200 CBCT images were selected according to predefined criteria. The DICOM file was imported into the i-CAT Vision software. In the panoramic screen, the middle of each tooth was selected, and in the sagittal window, the middle cross section was selected for performing the measurements using a computer. The vertical distance from the alveolar crest (BC) - cemento-enamel junction (CEJ) was measured. The width of the facial alveolar bone wall was measured at three locations: 1, 3, and 5 mm apical to BC. Descriptive statistics, frequency analyses, and multi-level comparisons were performed.
Results:
The sample consisted of 74 men and 126 women (mean age of 37.2 years; range 17-82 years). A total of 3618 teeth were assessed. There was no significant difference between the values of right and left sides, or between genders. However, statistically significant differences were observed between age groups at all levels. The distance from CEJ to BC varied from 0.4 to 4 mm, with an overall tendency to increase with age. The mean width of the facial alveolar bone wall at anterior teeth was 0.9 mm and increased toward posterior regions. Rarely, a width of 2 mm was yielded (0.6-1.8% for anterior teeth, 0.7-30.8% for posterior teeth). At a 5-mm distance from BC, minimal widths of facial alveolar bone were identified for the anterior teeth. The frequency of dehiscence ranged from 9.9% to 51.6% for anterior and 3.1% to 53.6% for posterior teeth, respectively.
Conclusion:
A thin facial alveolar bone wall was usually present in both jaws. Hence, for most patients, adjunctive bone augmentation may be needed when installing implants in areas of esthetic concern.
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.
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.
Cone-beam computed tomography (CBCT) has been used to assess alveolar bone changes after rapid palatal expansion. The purpose of this study was to investigate the accuracy of alveolar bone-height measurements from CBCT images with varied bone thicknesses and imaging resolutions.
Eleven maxillary specimens from 6-month-old pigs were measured for alveolar bone height (distance between drilled reference holes and alveolar crests) at 6 locations with a digital caliper, followed by CBCT scanning at 0.4-mm and 0.25-mm voxel sizes. Buccal alveolar bone of these locations was then reduced approximately by 0.5 to 1.5 mm, followed by CBCT rescanning with the same voxel sizes. The CBCT images were measured by using 3-dimensional software to determine alveolar bone height and thickness in buccolingual slices by independent, blinded raters. The specimens were subsequently cut into buccolingual sections at reference-hole levels, and direct bone height and thickness were measured from these sections. Intrarater and interrater repeatability and the differences between CBCT and direct measurements were assessed.
Excellent intrarater (intraclass correlations, r = 0.89-0.98) and good interrater (r = 0.64-0.90) repeatability values were found for alveolar bone-height measurements from the CBCT images. Before alveolar bone reduction, the thickness was much greater than the CBCT voxel size (0.4 mm), and bone-height measurements from the CBCT images were 0.5 to 1 mm more than the direct measurements (paired t tests, P <0.017 at most locations). After bone reduction, the thickness at the subcrest 1-mm level was near or below the CBCT voxel size (0.4 mm), and bone-height measurements from the CBCT images were 0.9 to 1.2 mm less than the direct measurements (paired t tests, P <0.017 at most locations). These measurement inaccuracies were substantially improved by decreasing the CBCT voxel size to 0.25 mm.
Alveolar bone-height measurements from conventional clinical 0.4-mm voxel size CBCT images might overestimate alveolar bone-height loss associated with rapid palatal expansion.
The aim of this study was to quantify laypersons' assessments of attractiveness, acceptability, and value of orthodontic appliances.
Orthodontic appliances were placed in a consenting adult, and digital images were captured, standardized, and incorporated into a computer-based survey. The survey displayed various images of orthodontic appliances for rating by a sample of adults (n = 50). Subjects rated each image for (1) attractiveness on a visual analog scale, (2) acceptability of placement of each appliance on themselves and their children, and (3) willingness to pay for each appliance for an adult or a child relative to a metal appliance standard. Rater reliability for the attractiveness, acceptability, and value ratings was assessed by rating 3 images twice.
Overall reliability values for attractiveness were intraclass correlation coefficient = 0.87 and kappa = 0.81 for acceptability and kappa = 0.88 for value ratings. The raters' annual income was not significant for attractiveness, acceptability, or value ratings. No significant difference was found between parent and child ratings for either the appliance acceptability or value ratings. Appliance brand, material, and wire were significant factors affecting attractiveness and value ratings. Attractiveness ratings were grouped in the following hierarchy of appliance types: alternative appliances such as clear trays and simulated lingual appliances > ceramic appliances > ceramic self-ligation appliances > all hybrid and stainless steel appliances. Acceptability ratings for all alternative and ceramic appliances were statistically equivalent, and statistically higher than those for other appliances. Standard metal braces had the lowest acceptability rate of 55%. The willingness-to-pay value of appliances relative to a metal standard appliance ranged from $629 for lingual appliances to $167 for a hybrid self-ligation appliance.
These findings show that a significant number of patients find commonly used appliances unattractive and unacceptable. Patients are willing to pay more money for appliances they deem more esthetic.
Our objective was to evaluate images produced by a commercially available cone-beam computed tomography (CBCT) machine (i-CAT model 9140-0035-000C, Imaging Sciences International, Hatfield, Pa) for measurement and spatial resolution (ie, the ability to separate 2 objects in close proximity in the image) for all settings and in all dimensions.
A custom phantom containing 0.3 mm diameter chromium metal markers approximately 5 mm apart in 3 planes of space was developed for analyzing distortion and measurement accuracy. This phantom was scanned in the CBCT machine by using all 12 commercially available settings. The distance between the markers was measured 3 times on the 3-dimensional images by using a Digital Imaging and Communications in Medicine (DICOM) viewer and was also measured 3 times directly on the phantom with a fine-tipped digital caliper. A line-pair phantom was used to evaluate spatial resolution. Thirty evaluators analyzed images and assigned a resolution from 0.2 to 1.6 mm according to the separation of the line pairs.
There were no statistically significant differences among the 3-dimensional images for any setting, in any dimension, or in images divided by thirds in terms of measurement accuracy. Comparison of the CBCT measurements to the direct digital caliper measurements showed a statistically significant difference (P <0.01). However, the absolute difference was <0.1 mm and is probably not clinically significant for most applications. The worst spatial resolution found was 0.86 mm. Spatial resolution was lower at faster scan times and larger voxel sizes.
This CBCT machine has clinically accurate measurements and acceptable resolution.
Ninety crania of Italian and Austrian males, 25-32 years old, coming from the ossurary of Custoza have been examined, (in all 2205 teeth) to determinate the presence and the frequency of dehiscences and fenestrations. All the crania presenting signs of serious stomatologic pathology have been rejected. Dehiscences are more frequent than fenestrations (7.30% vs 6.98%); dehiscences are more frequent in the mandible than in the maxilla (11.55% vs 1.86%), while fenestrations are more frequent in the upper alveolar arch than in the lower one (13.23% vs 2.10%); the upper right first molar is resulted to be the tooth showing the greatest number of defects (8.13% dehiscences and 49.69% fenestrations).
The purpose of this study was to evaluate the long-term stability of orthodontically induced changes in maxillary and mandibular arch form. Dental casts were evaluated before treatment, after treatment, and a minimum of 10 years after retention for 45 patients with Class I and 42 Class II, Division 1 malocclusions who received four first premolar extraction treatment. Computer generated arch forms were used to assess changes in arch shape over time. Buccal cusp tips of first molars, premolars, and canines plus mesial, distal, and central incisal aspects of incisors were marked, photocopied, and digitized in a standardized manner. An algorithm was used to fit conic sections to the digitized points. The shape of the fitted conics at each time period was described by calculating the parameter eccentricity; a small value represented a more rounded shape and a larger value represented a more tapered shape. Findings demonstrated a rounding of arch form during treatment followed by a change to more tapered. Arch form tended to return toward the pretreatment shape after retention. The greater the treatment change, the greater the tendency for postretention change. However, individual variation was considerable. The patient's pretreatment arch form appeared to be the best guide to future arch form stability, but minimizing treatment change was no guarantee of postretention stability.
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 establish cephalometric norms for African-American males and females, to compare these measurements with the findings of Alexander's "Alabama analysis," and to construct mesh templates for various age groups. The sample we evaluated included 71 African-Americans, divided into four groups: girls (8 to 12 years), boys (8 to 12 years), adolescent females (13 to 20 years), and adolescent males (13 to 20 years). The subjects met the following criteria: (1) normal Class I dental and skeletal relationship with minimal crowding, (2) balanced facial profile, and (3) no history of orthodontic treatment. The cephalometric radiographs were traced by hand, and linear and angular measurements were averaged to establish a mean with which to locate the anatomic landmarks used in the mesh diagram. In this study the African-Americans differed significantly from white Americans with regard to dental, skeletal, and soft tissue parameters. On average, the African-American subjects displayed larger SNA and ANB angles, more proclined lower incisors, and a more acute interincisal angle than did the white sample. Measurements between our African-American group and that of Alexander's African-American group in the "Alabama analysis" were consistent.
The relationship between loss of radiographic alveolar bone height and probing attachment loss has been studied by a number of investigators, with mixed results. Recent studies have found weak correlations and have suggested that the relationship between bone loss and attachment loss is complex, perhaps because changes in bone height and attachment level are separated in time.
The 85 patients in this report were part of a prospective estrogen replacement interventional study. All patients were in good oral health at entry and received annual oral prophylaxis as part of the study. Standard probing measurements were made with a pressure-sensitive probe at 6 sites on each tooth. Vertical bite-wing radiographs were taken of each patient, radiographs were digitized, and 6 linear measurements (corresponding to probing site measurements) were made from the cemento-enamel junction to the alveolar crest. These procedures were performed at baseline and at annual intervals; this study reports results after 2 years. Data were analyzed both by individual site and by averaging identical sites from all measured teeth for each patient.
Very weak direct relationships between change in alveolar bone height and change in attachment level were found in both the site data (r2=0.0022; P = 0.189) and the patient average data (r2=0.031; P= 0.104).
The changes in these patients were probably due to systemic changes in bone health rather than to periodontal disease. However, the weak correlations between changes in attachment level and bone height are similar to recent studies of periodontal disease. Our results support suggestions in the literature that the link between changes in attachment and alveolar bone height is complex, perhaps because changes in the 2 tissue types are separated by a considerable time delay.
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.
To examine the accuracy and precision of the Steiner prediction cephalometric analysis.
The sample consisted of 275 randomly selected patients, treated between 1970 and 1995 at a university department.
Lateral cephalograms before (T1) and after orthodontic treatment (T2) were analyzed using the Steiner analysis. A prediction of the final outcome at T2 for the variables ANB degrees, U1 to NA mm, L1 to NB mm, and Pg to NB mm was performed at T1. The difference between the actual outcome at T2 and the Steiner predicted value (SPV), which was done at T1, was calculated. Accuracy (mean difference between T2 and SPV) and precision (standard deviation of the mean prediction discrepancies) of the prediction were studied. Paired t-test was used to detect under- or overestimation of the predicted values.
The mean decrease in angle ANB was 1.4 +/- 2.7 degrees and for U1 to NA 2.0 +/- 2.6 mm, while L1 to NB increased 0.8 +/- 2.0 mm and Pg to NB 0.7 +/- 1.1 mm. The predicted values for the changes in ANB angle, the distance of upper incisor U1 to NA as well as the distance Pg to NB were significantly overestimated when compared with the actual outcome, while the change in the distance of lower incisor L1 to NB was underestimated.
The prediction of cephalometric treatment outcome as used in the Steiner analysis is not accurate enough to base orthodontic treatment decisions upon.
Long-term stability is an important measure of the success of orthodontic treatment. Research in the 1970s suggested that premolar extraction treatment had poor stability over the long term. The purpose of this prospective follow-up study was to investigate changes in intercanine widths and the irregularity index during the postretention phase in patients treated with and without extractions. Associations between the maxillary canine guidance angle and the mandibular intercanine widths and the mandibular irregularity index were also examined.
Two groups of 30 patients each, with and without premolar extractions, were studied and the results compared. Records were taken at pretreatment, at bracket removal, at the end of retention, and out of retention. The times out of retention were 6.3 years for the nonextraction group and 6.5 years for the extraction group. Stone casts were mounted on an articulator with an anatomical facebow and a central wax record. The measurements were made with a 3-dimensional digitizer.
Maxillary and mandibular intercanine distances behaved differently. The mandibular intercanine distance showed a net decrease between pretreatment and follow-up, whereas the maxillary arch had a net increase. The maxillary canine guidance angle at the end of retention, measured to the axis-orbital plane, was highly associated with relapse of mandibular anterior alignment and change of the mandibular intercanine distance.
Methods are needed that consider the anatomical configuration of the teeth for bracket selection before treatment. Individualized brackets (torque) should then be coordinated with the guidance angle of the maxillary teeth.
Dehiscence and fenestration in patients with Class I and Class II Division 1 malocclusion assessed with cone-beam computed tomography
- K Evangelista
- Vasconcelos Kdf
- A Bumann
- E Hirsch
- M Nitka
- Mag Silva
Evangelista K, Vasconcelos KdF, Bumann A, Hirsch E, Nitka M,
Silva MAG. Dehiscence and fenestration in patients with Class I
and Class II Division 1 malocclusion assessed with cone-beam
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