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An Assessment of the Effects of Orthodontic Treatment after Apexification of Traumatized Immature Permanent Teeth: A Retrospective Study
Abstract
Introduction
Root resorption may occur in traumatized necrotic teeth that have undergone apexification following orthodontic treatment. This study examined the effects of orthodontic treatment on the outcome of apexification.
Methods
This retrospective study included 36 children presenting with anterior permanent traumatized teeth with immature roots, who were treated by apexification and root canal treatment. The Orthodontic group consisted of 17 children with 24 teeth that were subjected to orthodontic treatment after apexification. The Control group consisted of 19 children with 21 teeth that underwent only apexification without orthodontic treatment. Almost half of the teeth in both groups underwent apexification with calcium hydroxide, whereas the other half were treated with mineral trioxide aggregate. The effects of sex, stage of root development, and apexification material on the outcomes of apexification were analyzed and compared between the two groups.
Results
Apexification was successful in 88% of cases after at least 5 years of follow-up. Neither apexification technique nor sex had a significant effect on treatment outcome. The stage of root development had a positive effect on outcome, although it was not statistically significant. Some root resorption (average 0.3 mm) was observed after orthodontic treatment, whereas teeth that underwent apexification without orthodontic treatment exhibited some root elongation (average 0.1 mm). This difference was highly significant.
Conclusions
Minor root resorption was observed in the Orthodontic group compared to a minor increase in root length in the Control group. Orthodontic movement of immature traumatized teeth after apexification appears to be safe.
The literature is replete with articles describing the many and varied interactions between endodontic treatment and orthodontic tooth movement (OTM), often reporting conflicting views and findings, which creates confusion for clinicians. Original research and review articles have described aspects such as apical root resorption and potential pulpal complications of teeth related to OTM. Some interactions are of relatively minor clinical significance, whilst others may have adverse consequences. A history of dental trauma before or during OTM further complicates the interactions. This review re-assesses the historical literature on endodontic-orthodontic interactions in light of more recent research and presents guidelines for managing clinical situations involving both disciplines. © 2023 Australian Dental Association.
Introduction
Orthodontically induced external root resorption (OIERR) has been labeled an unavoidable consequence of orthodontic tooth movement (OTM). The objective of this study was to investigate the change in surface area (mm²) and volume (mm³) of endodontically treated teeth (ETT) compared to contralateral teeth with a vital pulp (VPT) following OTM.
Methods
Seventy-six teeth were included in this retrospective analysis: ETT (n=38) and VPT (n=38). All teeth were evaluated using CBCT imaging at two time periods: before OTM (T1) and after OTM (T2). Study teeth were segmented to include all areas contained within the lamina dura and then were converted into a mesh model for data calculation. The surface area (mm²) and volume (mm³) of each tooth was calculated at T1 and T2 based on the number of cubic voxels present within the mesh model. Statistical analysis was performed using a linear mixed-effects model.
Results
The average change in surface area following OTM in ETT was 13.01 mm², and 19.95 mm² in VPT (p<0.05). The average percent change in surface area following OTM in ETT was 2.09%, and 3.38% in VPT (p<0.05). The average change in volume following OTM in ETT was 22.48 mm³, and 32.44 mm³ in VPT (p<0.05). The average percent change in volume following OTM in ETT was 2.62%, and 4.10% in VPT (p<0.05).
Conclusions
The results from this study suggest that ETT are less susceptible to root resorption following OTM than their vital counterparts.
Traumatic dental injuries (TDIs) occur most frequently in children and young adults. Older adults also suffer TDIs but at significantly lower rates than individuals in the younger cohorts. Luxation injuries are the most common TDIs in the primary dentition, whereas crown fractures are more commonly reported for the permanent teeth. Proper diagnosis, treatment planning and follow‐up are very important to assure a favorable outcome. These updates of the International Association of Dental Traumatology’s (IADT) Guidelines include a comprehensive review of the current dental literature using EMBASE, MEDLINE, PUBMED, Scopus and Cochrane Databases for Systematic Reviews searches from 1996‐2019 and a search of the journal Dental Traumatology from 2000‐2019.
The goal of these guidelines is to provide information for the immediate or urgent care of TDIs. It is understood that some follow‐up treatment may require secondary and tertiary interventions involving dental and medical specialists with experience in dental trauma.
As with previous guidelines, the current working group included experienced investigators and clinicians from various dental specialties and general practice. The current revision represents the best evidence based on the available literature and expert opinions. In cases where the published data were not conclusive, recommendations were based on the consensus opinions of the working group. They were then reviewed and approved by the members of the IADT Board of Directors.
It is understood that guidelines are to be applied using careful evaluation of the specific clinical circumstances, the clinician’s judgment and the patient’s characteristics, including the probability of compliance, finances, and a clear understanding of the immediate and long‐term outcomes of the various treatment options versus non‐treatment. The IADT does not, and cannot, guarantee favorable outcomes from adherence to the Guidelines. However, the IADT believes that their application can maximize the probability of favorable outcomes.
Background
The aim of this study was to compare the external apical root resorption (EARR) in patients receiving fixed orthodontic treatment with self-ligating or conventional brackets. Methods
Studies comparing the EARR between orthodontic patients using self-ligating or conventional brackets were identified through electronic search in databases including CENTRAL, PubMed, EMBASE, China National Knowledge Infrastructure (CNKI) and SIGLE, and manual search in relevant journals and reference lists of the included studies until Apr 2016. The extraction of data and risk of bias evaluation were conducted by two investigators independently. The original outcome underwent statistical pooling by using Review Manager 5. ResultsSeven studies were included in the systematic review, out of which, five studies were statistically pooled in meta-analysis. The value of EARR of maxillary central incisors in the self-ligating bracket group was significantly lower than that in the conventional bracket group (SMD −0.31; 95% CI: −0.60–−0.01). No significant differences in other incisors were observed between self−ligating and conventional brackets. Conclusions
Current evidences suggest self-ligating brackets do not outperform conventional brackets in reducing the EARR in maxillary lateral incisors, mandible central incisors and mandible lateral incisors. However, self-ligating brackets appear to have an advantage in protecting maxillary central incisor from EARR, which still needs to be confirmed by more high-quality studies.
Objective
The aim of this meta-analysis was to investigate the effect of orthodontic treatment on root resorption of endodontically treated teeth compared to vital teeth.
Materials and methods
A literature search was conducted in 18 electronic databases. Review articles and relevant articles were searched for cross-references. Two independent reviewers screened all articles according to predefined inclusion and exclusion criteria and extracted the corresponding data. The pooled estimate of mean difference of root resorption weighted by the fixed-effect model and the corresponding 95 % confidence intervals (CIs) were used to construct a forest plot by implementing the “RevMan 5.1” software. Quality and heterogeneity assessments as well as publication bias evaluation and sensitivity analyses were performed. Inter-reviewer agreement for data selection, data extraction and quality analysis was evaluated by Cohen’s kappa.
Results
Six out of 1,942 original papers met the inclusion criteria. Four out of six studies were included in the quantitative analysis. Root resorption was less in endodontically treated teeth than in vital teeth (MD = −0.48 mm; 95 % CI = −0.81 to −0.14 mm). The funnel plot indicated no evidence of publication bias, while no data heterogeneity was present (I
2 = 0 %). However, the overall quality of the included studies was considered as “low.”
Conclusions
Following orthodontic treatment, endodontically treated teeth exhibit relatively less root resorption than teeth with vital pulps.
Clinical relevance
Clinicians should consider orthodontic movement of endodontically treated teeth as a relatively safe clinical procedure.
This study examined risk factors associated with incisor injury in 3396 third and fourth grade school children in Alachua County, Florida. One of six orthodontists completed a standardized examination form for each child to assess severity of incisor injury, gender, age, race, skeletal relationships, morphologic malocclusion, incisor exposure, interlabial gap, TMJ sounds, chin trauma, and history of lower facial trauma. One in five (19.2%) exhibited some degree of incisor injury. This was limited to a single tooth in 73.1% of those with injury, while enamel injury predominated (89.4%). The majority of the injuries (75.4%) were localized in the maxillary arch, with central incisors the most frequently traumatized. Chi-square tests of association indicated that gender, race, school, orthodontist, history of lower facial trauma, chin trauma, profile, and maxillary and mandibular horizontal positions were associated with incisor injury (P < 0.05). Wilcoxon rank sum tests identified differences in age, overjet, time of screening, and interlabial gap between those with and without injury (P < 0.05). Results of logistic regression analyses indicated risk of incisor injury was greater for children who had a prognathic maxilla, a history of trauma, were older, were male, and had greater overjet and mandibular anterior spacing.
The purpose of this study was to compare the severity of apical root resorption occurring in patients treated with a standard edgewise and a straight-wire edgewise technique, and to assess the influence of known risk factors on root resorption incident to orthodontic treatment. The sample consisted of 80 patients with Angle Class II division 1 malocclusions, treated with extraction of at least two maxillary first premolars. Variables recorded for each patient included gender, age, ANB angle, overjet, overbite, trauma, habits, invagination, agenesis, tooth shedding, treatment duration, use of Class II elastics, body-build, general factors, impacted canines, and root form deviation. Forty patients were treated with a standard edgewise and 40 with a straight-wire edgewise technique, both with 0.018-inch slot brackets. Crown and root lengths of the maxillary incisors were measured on pre- and post-treatment periapical radiographs corrected for image distortion. Percentage of root shortening and root length loss in millimetres were then calculated. There was significantly more apical root resorption (P < 0.05) of both central incisors in the standard than in the straight-wire edgewise group. No significant difference was found for the lateral incisors. Root shortening of the lateral incisors was significantly associated with age, agenesis, duration of contraction period (distalization of incisors), and invagination, while root shortening of the central incisors was related to treatment group and trauma.
The purpose of the study was to investigate root lengthening during orthodontic treatment in relation to the age of the patient, the developmental stage of the root, and the anticipated growth. Specifically, the potential benefit of treating young teeth was addressed. The sample consisted of 80 patients with Angle Class II division 1 malocclusions, treated with extraction of at least two maxillary first premolars, and edgewise technique with 0.018-inch slot brackets. Additionally, a cross-sectional control group of 66 untreated individuals matched to gender, and pre- and post-treatment age of the experimental group was included. Crown and root lengths of the maxillary incisors were measured on peri-apical radiographs before and after treatment, and corrected for image distortion. The stage of root development before treatment was recorded. Root elongation during treatment was found for 50 out of the 280 examined teeth. Age at treatment start was significantly higher among the patients showing root shortening of the lateral incisors during treatment than among those showing root elongation (P < 0.05). The stage of root development was significantly related to the direction of root length change, i.e. shortening or elongation. Roots elongated during treatment did not differ in length from untreated teeth of similarly aged individuals. There was no significant difference in the extent of root lengthening between the roots elongated during treatment and the normal root lengthening in age-matched untreated individuals. Post-treatment root length was significantly related to pre-treatment age. Roots that were incompletely developed before treatment reached a significantly greater length than those that were fully developed at the start of treatment. The results of this study show a definite advantage for younger teeth with regard to post-treatment root length. This finding may influence treatment planning strategy.
This was the radiographic evaluation of 15 maxillary incisors apexification treatment carried out on 7-9 years old patients with periapical pathology due to pulpal necrosis after dental trauma.
The treatment consisted of two phases. The aim of first phase was the formation of a calcified apical barrier through calcium hydroxide medications repeated twice with a three months interval. The aim of the second phase was the obturation of the root canal system once achieved a radiographic evidence of the formation of an apical barrier. The treated teeth were radiographed at six months and then periodically once a year for a period of 7 and 13 years.
The radiographic analysis allowed to underline three different kinds of apical formation: a physiological development of the apical portion with a final root length equal to the contralateral tooth; the formation of a cap tissue and an apical development with the final root length slightly shorter than the contralateral tooth; or the formation of different layers of mineralised tissue that aggregate together trough the years.
Apexification is not a static phenomenon and the apexified area undergoes through the years to a conspicuous readjustment involving bone, apical root tissues and root filling material.
The aim of this study was to compare mineral trioxide aggregate (MTA) with calcium hydroxide [Ca(OH)2] clinically and radiographically as materials used to induce root-end closure in necrotic permanent teeth with immature apices (apexification).
Fifteen children, each with at least 2 necrotic permanent teeth requiring root-end closure (apexification), were selected for this study. All selected teeth were evenly divided into 2 test groups. In group 1, the conventional calcium hydroxide apexification (control) was performed, whereas in group 2, the MTA apexification (experimental) was done. The children were recalled for clinical and radiographic evaluations after 3, 6, and 12 months.
The follow-up evaluations revealed failure due to persistent periradicular inflammation and tenderness to percussion detected at 6 and 12 months postoperative evaluation in only 2 teeth treated with Ca(OH)2. The remaining 13 teeth appeared to be clinically and radiographically successful 12 months postoperatively. None of the MTA-treated teeth showed any clinical or radiographic pathology.
Mineral trioxide aggregate showed clinical and radiographic success as a material used to induce root-end closure and is a suitable replacement for calcium hydroxide for the apexification procedure.
Introduction
The aim of this study was to verify less resorption of incompletely developed roots compared with those that were fully developed during the same orthodontic treatment and to test the value of the amount of external apical root resorption for predicting tooth development.
Methods
A sample of 524 patients aged 10-15 years was selected following the inclusion criteria. For each subject, pretreatment and posttreatment digital panoramic and lateral radiographs were collected, and tooth development was determined from each radiograph. Through calculations, the amount of root resorption was assessed by a created and scientific approach for large-scale application using radiographs with only 8 measurement indexes for each patient. Other basic information and treatment parameters regarded as possible risk factors were also collected from standardized recordings or radiographs. The root length between the groups or in the single group were compared with t tests and correlation analyses. Linear univariate and multivariate regression analyses were used to test identify predictors for root resorption and to develop a prediction model.
Results
There was a statistically significant difference in the amount of root resorption with tooth development before correction (P <0.001) as well as after correction (P = 0.002). There was a statistically significant correlation (P <0.001) but no difference between pretreatment and posttreatment root length in the immature tooth group because of less root resorption. In the multivariate analyses, tooth development (P <0.001), treatment duration, apex horizontal movements, apex vertical movements, and previous orthodontic treatment were included in the final model as risk factors, and tooth development had the highest beta value.
Conclusions
There is an association between root resorption and tooth development, and tooth development is an important predictor of root resorption. Patients with immature teeth are at a much lower risk of apical root resorption.
The principles of formation, renewal, and eruption of teeth are discussed. Numerous genetic aberrations may affect the formation and eruption of teeth. Cleidocranial dysplasia (CCD), caused by mutations in the runt‐related transcription factor 2 (RUNX2) gene, is such a condition. The dental phenotype includes problems in both tooth formation (multiple supernumerary permanent teeth) and tooth eruption (lack of shedding of primary teeth and delayed or arrested eruption of permanent teeth). Clinical studies, animal models, and molecular biology studies have documented that RUNX2 is of paramount importance for osteoblast differentiation, for regression of the dental lamina, and for osteoclastogenesis in the dental follicle and the periodontal ligament. Jensen & Kreiborg, 25 yr ago, proposed a treatment strategy to be applied to patients with CCD, focussing on the importance of early treatment to promote spontaneous eruption of permanent teeth through extraction of primary teeth, surgical removal of supernumerary teeth, and removal of bone covering the first formed permanent teeth at the time when root formation of the permanent teeth has reached half or two‐thirds of their final length. This strategy still seems valid and seems to lead to reduction in the burden of care for patients compared with the treatment protocols otherwise recommended.
Introduction:
There is a lack of research to support the belief that root canal treatment can be considered for stopping or decreasing external apical root resorption (EARR). There is conflicting evidence as to whether root-filled teeth are more or less likely to experience EARR after orthodontic treatment. The purpose of this study was to compare the degree of EARR of root-filled teeth with that of contralateral teeth with vital pulp after fixed orthodontic treatment.
Methods:
The study sample consisted of 35 patients aged 25.23 ± 4.92 years who had at least 1 root-filled tooth before orthodontic treatment. Digital panoramic radiographs of each patient taken before and after orthodontic treatment were used to measure the EARR. The Student t test for matched pairs and the Pearson correlation analysis were applied.
Results:
The mean EARR values were 0.22 (0.14, 0.35) for root-filled teeth and 0.87 (0.59, 1.31) for contralateral teeth with vital pulp, indicating significantly less EARR for root-filled teeth compared with the contralateral teeth with vital pulp after orthodontic treatment. EARR was influenced by the patient's age, treatment duration, treatment type, and periapical pathosis, but not by tooth type and sex.
Conclusions:
Root-filled teeth appear to be associated with significantly less EARR than are contralateral teeth with vital pulp. This study suggests that the possible complication of EARR in root-filled teeth may not be an important consideration in orthodontic treatment planning, and root canal treatment can be considered for stopping or decreasing EARR when severe EARR occurs during orthodontic treatment.
Unlabelled:
Abstract - Background: The aim of this in vitro study was to assess the long-term fracture resistance of human immature permanent teeth filled with BioAggregate (BA), mineral trioxide aggregate (MTA) and calcium hydroxide (CH).
Materials and methods:
The study consisted of single rooted premolar teeth with immature root formation extracted for orthodontic reasons. A total of 28 immature premolars with average root length of 10.7 mm and apical diameter of 3 mm were included in the study. The pulps were extirpated and the canals were prepared using an apical approach. The teeth were randomly assigned to four groups: Group I: DiaRoot(®) BA (DiaDent, Burnaby, BC, Canada), Group II: Angelus MTA (MTA-A; Angelus, Londrina, Brazil), Group III: ProRoot(®) MTA (MTA-PR; Dentsply, Tulsa, OK, USA), Group IV: CH (Sultan Chemists Inc., Englewood, NJ, USA). The teeth were placed in saline solution at 4°C for 1 year. The root of each tooth was then embedded in an acrylic resin block. All specimens were loaded at a crosshead speed of 1 mm min(-1) in an Instron testing machine and the peak loads up to fracture were recorded. Data were analysed statistically by Kruskal-Wallis and Mann-Whitney U-tests.
Results:
Mean (±SD) failure loads (MPa) were: 37.69 ± 14.43 for BA group, 32.94 ± 8.15 for MTA-A group, 28.74 ± 9.49 for MTA-PR group and 23.18 ± 8.48 for CH group. The BA group exhibited the highest fracture resistance and the CH group showed the lowest resistance to fracture. Significant differences (P < 0.05) in fracture resistance were found between the DiaRoot-BA and CH groups, and also between the MTA-A and CH groups.
Conclusion:
Within the limitations of this study, data suggest that DiaRoot-BA-filled immature teeth demonstrate higher fracture resistance than other groups at 1 year. Considering the long-term risk of cervical root fracture associated with immature teeth, the use of DiaRoot-BA as a root canal filling material appears to be the most advantageous of the materials tested.
To determine whether root filled teeth and those with vital pulps exhibit a similar degree of external root resorption (ERR) as a consequence of orthodontic treatment.
The study sample consisted of 77 patients, with a mean age of 32.7 +/- 10.7 years, who had one root filled tooth before completion of multiband/bracket orthodontic therapy for at least 1 year. For each patient, digital panoramic radiographs taken before and after orthodontic treatment were used to determine the proportion of external root resorption (PRR), defined as the ratio between the root resorption in the root filled tooth and that in its contralateral tooth with a vital pulp. The student's t-test, anova and logistic regression analysis were used to determine statistical significance.
The mean PRR was 1.00 +/- 0.13, indicating that, in the total sample, there were no significant differences in root resorption in the root filled teeth and their contralateral teeth with vital pulps. Multivariate logistic regression analysis suggested that PRR was significantly greater in incisors (P = 0.0014; odds ratio = 6.2885, C.I. 95% = 2.0-19.4), compared to other teeth, and in women (P = 0.0255; odds ratio = 4.2, C.I. 95% = 1.2-14.6), compared to men.
There was no significant difference in the amount or severity of external root resorption during orthodontic movement between root filled teeth and their contralateral teeth with vital pulps.
This systematic review evaluated root resorption as an outcome for patients who had orthodontic tooth movement. The results could provide the best available evidence for clinical decisions to minimize the risks and severity of root resorption.
Electronic databases were searched, nonelectronic journals were hand searched, and experts in the field were consulted with no language restrictions. Study selection criteria included randomized clinical trials involving human subjects for orthodontic tooth movement, with fixed appliances, and root resorption recorded during or after treatment. Two authors independently reviewed and extracted data from the selected studies on a standardized form.
The searches retrieved 921 unique citations. Titles and abstracts identified 144 full articles from which 13 remained after the inclusion criteria were applied. Differences in the methodologic approaches and reporting results made quantitative statistical comparisons impossible. Evidence suggests that comprehensive orthodontic treatment causes increased incidence and severity of root resorption, and heavy forces might be particularly harmful. Orthodontically induced inflammatory root resorption is unaffected by archwire sequencing, bracket prescription, and self-ligation. Previous trauma and tooth morphology are unlikely causative factors. There is some evidence that a 2 to 3 month pause in treatment decreases total root resorption.
The results were inconclusive in the clinical management of root resorption, but there is evidence to support the use of light forces, especially with incisor intrusion.
Several case reports on endodontic regeneration involving immature permanent teeth have recently been published. These case series have used varying treatments to achieve endodontic regeneration including triple antibiotic paste, Ca(OH)(2), and formocresol. However, no study has analyzed the overall results.
In this retrospective study, we collected radiographs from 54 published and unpublished endodontic regenerative cases and 40 control cases (20 apexification and 20 nonsurgical root canal treatments) and used a geometrical imaging program, NIH ImageJ with TurboReg plug-in, to minimize potential differences in angulations between the preoperative and recall images and to calculate continued development of root length and dentin wall thickness.
The comparison to the 2 control groups provided a validation test for this method. Forty-eight of the 54 regenerative cases (89%) had radiographs of sufficiently similar orientation to permit analysis. The results showed regenerative endodontic treatment with triple antibiotic paste (P < .001) and Ca(OH)(2) (P < .001) produced significantly greater increases in root length than either the MTA apexification or NSRCT control groups. The triple antibiotic paste produced significantly greater differences in root wall thickness than either the Ca(OH)(2) or formocresol groups (P < .05 for both). The position of Ca(OH)(2) also influenced the outcome. When Ca(OH)(2) was radiographically restricted to the coronal half of the root canal system, it produced better results than when it was placed beyond the coronal half.
Ca(OH)(2) and triple antibiotic paste when used as an intracanal medicament in immature necrotic teeth can help promote further development of the pulp-dentin complex.
This study evaluated periapical tissue healing and orthodontic root resorption of endodontically treated teeth sealed with calcium hydroxide in dogs. The sample consisted of three contralateral pairs of maxillary incisors and two contralateral pairs of mandibular incisors in each of two dogs using a split mouth design. After biomechanical preparation of the teeth in the first group (n = 10), a Ca(OH)(2) dressing was placed for 14 days before root canal filling with Ca(OH)(2)-based sealer (Sealapex) and gutta-percha points. In the second group (n = 10), root canals were obturated immediately after the mechanical preparation with gutta-percha points and zinc oxide and eugenol (ZOE)-based sealer (Endofill). After completion of endodontic treatment, the teeth were moved with an orthodontic appliance with a calibrated force of 200 g, reactivated every 21 days. After 105 days, the animals were killed and the teeth were removed upon completion of active treatment, without a period of recovery, and prepared for histomorphological analysis. All sections of each tooth were graded subjectively on a scale from one to four to obtain the average of the 16 histomorphological parameters analysed. Evaluation of the differences between the two treatment protocols was made with Mann-Whitney U-test. It was observed that the teeth treated with Ca(OH)(2)-based materials provided better outcomes (P = 5%), with complete repair of all root resorption areas, high rate of biological closure of the main canal and apical accessory canals by newly formed cementum, less intense and extensive chronic inflammatory infiltrate, and better organization of the periodontal ligament. Under the tested conditions, Ca(OH)(2)-based materials had a favourable action on periapical tissue healing and repair of orthodontic root resorption in endodontically treated dogs' teeth.
Forty-two patients consecutively treated by the Begg method, all of whose first premolars had been extracted before orthodontic treatment, were examined roentgenologically by an intraoral technique on three to four occasions. The examinations were made before treatment, during treatment (before uprighting of tipped teeth), after completion of treatment, and 6 months after completion of treatment.In order to determine the occurrence and degree of root resorptions during the treatment period, a root resorption index was constructed. The reproducibility of the resorption index was studied by two observers.For assessment of the incidence and degree of root resorptions, the series of roentgenograms from each patient were examined simultaneously. The reproducibility of the simultaneous evaluation was also studied.In all of the forty-two cases treated, root resorption was recorded in the last roentgenologic examination.Before treatment small resorptions were found in 4 per cent of the teeth. Already, before uprighting of the tipped teeth, irregular root contours (score 1), probably caused by resorptions, and resorptions < 2 mm. (score 3) were recorded for 25 per cent and 31 per cent, respectively, of the teeth. There was no visible resorption in 42 per cent of the teeth.At the completion of treatment resorption < 2 mm. (score 3) predominated with 48 per cent, resorption of 2 mm.—one third of the root (score 5) occurred in 3 per cent, and no visible resorption occurred in 23 per cent of the teeth.When analyzing the percentage distribution of different degrees of root resorption in the teeth examined, we found that the relatively high frequency of root resorption before uprighting of tipped teeth increased slightly at completion of treatment. The resorption increased more for the upper central incisors, which were subjected to root torque, than for the upper lateral incisors.The incidence of root resorption 6 months after completion of treatment was highest at the lower central incisors (95 per cent). The upper central and lateral incisors showed an incidence of 90 and 87 per cent, respectively, and the lower and upper canines showed an incidence of 79 and 72 per cent, respectively. The lower premolars showed the lowest incidence of root resorption (53 per cent).The teeth that exhibited root resorption prior to treatment developed more resorption than the average during orthodontic treatment. This was especially marked for the upper incisors.
The reaction of previously traumatized teeth to orthodontic force application was investigated. Four groups of children were examined: group T comprised 56 children who encountered trauma to their maxillary incisors; group O comprised 29 orthodontic patients with intact incisors; group TO comprised 28 previously traumatized orthodontic patients; and group C served as the control group (n = 26). Orthodontic treatment was restricted to tipping movement executed only by means of removable appliances. Groups T, O, and TO were followed up longitudinally by means of clinical and radiographic examinations. In most of the cases the reported trauma occurred to teeth with completed roots and affected the crown only. Group TO presented the highest, though relatively moderate, prevalence of root resorption (27.8 per cent) and was followed by groups O and T (6.7 and 7.8 per cent, respectively) while in the control group no resorption was observed. Electrical pulp testing revealed the highest prevalence of loss of tooth vitality in group TO (7.3 per cent) in which the highest prevalence of pulp obliteration was also found. It can be concluded that the combination of trauma with orthodontic tipping renders the teeth more susceptible to complications, especially to root resorption and loss of vitality.
The purpose of this study was to determine whether vital and endodontically treated incisors exhibit a similar severity of apical root resorption in response to orthodontic treatment. Forty-three patients who had one or more endodontically treated incisors before orthodontic treatment and who exhibited signs of apical root resorption after treatment were studied. In each patient the vital contralateral incisor served as a control. Vital incisors resorbed to a significantly greater degree than endodontically treated incisors (p less than or equal to 0.05). When patients were separated by gender, control teeth in males exhibited a statistically significant increase in resorption over control teeth in females. No significant differences were apparent between males and females when endodontically treated incisors were compared.
The purpose of this study was to determine if apical root resorption associated with orthodontic treatment continues after the termination of active treatment (that is, the removal of fixed appliances). A sample of 45 subjects who had experienced root resorption during treatment was selected from the orthodontic clinic at the State University of New York at Buffalo. The length of the maxillary central incisors was measured from lateral cephalometric radiograms taken before treatment, after active treatment, and after retention. From these data, the resorption occurring during and after active treatment was calculated. The mean amount of root resorption during active treatment was 2.93 mm. The mean amount of root resorption during the posttreatment period was 0.1 mm. There was a statistical difference between these two means using the Student's t test at the 0.05 level of significance. The reliability coefficient comparing the first tracings and measurements in the 19 cases that were retraced and remeasured was r = 0.993. The data from this radiographic study support the hypothesis that root resorption associated with orthodontic treatment ceases with the termination of active treatment. There was also evidence to suggest that when posttreatment root resorption does occur, it is not necessarily associated with large amounts of root resorption during the active treatment period. It is more likely associated with other factors, such as traumatic occlusion and active force-delivering retainers.
The purpose of the study was to investigate whether root resorption of the upper incisors occurs during intrusion of maxillary incisors. It examines the possibility of a relationship between the amount of root shortening and duration of the intrusive force. The ratio of root length before and after intrusion was compared in 20 patients. In 66 incisors with an intrusion period of 29 weeks, an intrusion of 3.6 mm was performed. The control group consisted of 15 patients who underwent no orthodontic treatment. Consequently, 58 incisors had no intrusion. The follow-up time between 2 measurements was +/- 28 weeks. The findings clearly showed root shortening after intrusion. A mean resorption of 18% of the original root length was found. In comparison, none of the control patients showed root shortening. No correlation has been found between the amount of resorption and the amount and duration of intrusion. In combination with the apical deflection of the root, the nasal floor was occasionally a limiting factor for intrusion and this may have caused root resorption.
The effect of calcium hydroxide treatments and apicaldiameter on the time of apexification and type of apical barrier was studied in 51 pulpless immature permanent incisors. The apical diameter ranged from 2 to 3.5 mm. The root canals were debrided before receiving a calcium hydroxide treatment (Calasept). Patients were recalled monthly for evaluation. The root canals were reinjected with Calasept whenever voids were evident radiographically.
An apical barrier developed in 96% of the teethwithin 3 to 10 months and the types were 65% cap, 25% bridge, and 10% ingrown wedge.
Many of the teeth, 78%, developed an apical barrierwithin the 5- to 6-month period. There were fewer Calasept treatments regardless of the apical diameter, when apexification was faster.
A population of 400 patients, comprising 637 luxated permanent teeth was studied prospectively with respect to the development of pulp necrosis after luxation injuries. The patients were treated for traumatic dental injuries over a period of 10 years. While initial treatment was provided according to established treatment guidelines by the attending oral surgeon at the emergency room, follow-up examination and treatment was provided by one oral surgeon. It appeared that pulp necrosis occurred soon after injury, within 3 months after concussion, within the 1st yr after subluxation and extrusion, and might be diagnosed up to 2 yr after lateral- and intrusive luxation. While many factors, when considered one at a time, were found to have a significant or nearly significant died on the development of pulp necrosis (i.e. type of injury, age of patient, stage of root development, degree of dislocation, reduction/repositioning procedure, type of fixation, restorations in place at the lime of injury), a multivariate regression analysis revealed that when the type of injury (diagnosis) and stage of root development were taken into account, the effect of other factors was no longer significant. The risk of pulp necrosis increased with the extent of injury, i.e. concussion and subluxation represented the least risk, followed in ascending order by extrusive-, lateral-, and intrusive luxation. Moreover, teeth with completed root formal ion demonstrated a greater risk of pulp necrosis than teeth with incomplete root formation. No treatment effect could be demonstrated. However, as treatment was performed according to established guidelines, which might introduce bias, it would appear justified to conduct randomized clinical studies in order to determine the value of different forms of treatment (e.g. reduction and fixation of luxated teeth) to improve the prognosis with respect to the development of pulp necrosis after injury. In conclusion, the major factors influencing development of pulp necrosis after luxation injuries appear to be the extent of the initial injury to the pulp and periodontium, as reflected by the type of luxation, and the repair potential of the injured tooth, as reflected by the stage of root development.
Clinical experience illustrates the success of endodontic therapy based on the normal physiologic pattern of root development. The technic described brings about the resumption of apical development; after which the root canal can be obliterated by conventional lateral condensation technics.
A series of twenty-one incompletely developed pulpless human teeth have been treated conservatively with calcium hydroxide and methylcellulose as a root-filling material. Observation times varied from 14 to 75 months.Elimination of bacteria was achieved by routine endodontic procedures in conjunction with irrigation and dressing with an aqueous solution of 0.03 per cent chlorhexidine and 0.3 per cent cetrimide.Of the twenty-one cases, fourteen showed complete, five partial, and two no root development during the period of observation. Periapical repair was complete in twenty of the twenty-one cases and is proceeding satisfactorily in the remaining case. A clinical evaluation of success showed nineteen cases to be successful and two doubtful, with no failures over the period of observation.Histologic material has been presented which revealed that new tissue had been formed, both apically and within the old canal. This consisted of pulp, interglobular dentine, cementum, and attached periodontal membrane fibers. Two calcified layers of interglobular dentine extended into the old canal and lined it. However, no calcific barrier was present at the coronal extremity of the canal. Thick deposits of cellular and acellular cementum not only covered the newly formed tissue but extended beyond the junction with the old root.The results of the clinical series and the histologic material support the conservative approach to the treatment of pulpless, incompletely developed teeth. The method is indicated because of its simplicity, the lack of surgical trauma, and the improved prognosis afforded by the further root development.
The incidence and extent of apical root resorption in maxillary incisors were studied radiographically in 719 consecutively treated orthodontic patients. Mean age at start of treatment was 12.8 years and mean observation time 3.6 years in both sexes. Root lengths were measured to the nearest 1/10 mm on standardized intra-oral radiographs taken before and after treatment. Mean root shortening for the four incisors were 0.73 mm and 0.67 mm for girls and boys respectively. When using the most severe single root resorption per patient as a parameter the mean was 1.34 mm for both sexes.
A statistical search for clinical risk factors in apical root resorption indicated that patients starting treatment after 11 years of age experienced significantly more root resorption than patients starting earlier, even when taking residual root growth into account. Highly significant risk factors were: previous trauma, the correction of impacted maxillary canines, the use of rectangular archwires and Class II elastics. Fixed appliances caused significantly more apical root resorption than removable appliances.
Sex, overbite, overjet and the length of time with bands on the teeth were not closely related to the amount of apical root resorption.
This study determined the chemical composition, pH, and radiopacity of mineral trioxide aggregate (MTA), and also compared the setting time, compressive strength, and solubility of this material with those of amalgam, Super-EBA, and Intermediate Restorative Material (IRM). X-ray energy dispersive spectrometer in conjunction with the scanning electron microscope were used to determine the composition of MTA, and the pH value of MTA was assessed with a pH meter using a temperature-compensated electrode. The radiopacity of MTA was determined according to the method described by the International Organization for Standardization. The setting time and compressive strength of these materials were determined according to methods recommended by the British Standards Institution. The degree of solubility of the materials was assessed according to modified American Dental Association specifications. The results showed that the main molecules present in MTA are calcium and phosphorous ions. In addition, MTA has a pH of 10.2 initially, which rises to 12.5 three hours after mixing. MTA is more radiopaque than Super-EBA and IRM. Amalgam had the shortest setting time (4 min) and MTA the longest (2 h 45 min). At 24 h MTA had the lowest compressive strength (40 MPa) among the materials, but it increased after 21 days to 67 MPa. Finally, except for IRM, none of the materials tested showed any solubility under the conditions of this study.
A new radiographic method was developed for measuring changes in root length. With this technique, orthodontic intrusion was investigated as a potential cause of apical root resorption of maxillary incisors. The experimental group consisted of 17 patients with excessive overbite who were treated with a Burstone-type intrusion arch, which delivered a low level of force (about 15 gm per tooth). A control group was made up of 17 patients in full-arch fixed appliances who were randomly selected. After a period of approximately 4 months, the intrusion group had only slightly more root resorption than the controls, 0.6 mm versus 0.2 mm (statistically significant difference). Intrusion measured at the center of resistance of the central incisor averaged 1.9 mm. The amount of resorption was not correlated with the amount of intrusion. A weak correlation, r = 0.45, was found between resorption and movement of the apex (i.e., in addition to intrusion, there was often palatal root movement). Results of this study seem to indicate that intrusion with low forces can be effective in reducing overbite while causing only a negligible amount of apical root resorption.
The aim of this investigation was to study root resorption after application of a weekly controlled, continuous orthodontic force of 50 cN (approximately 50 gm). Fifty-six maxillary premolars in 18 boys and 38 girls (mean age 13.8 years) were moved buccally with a fixed orthodontic appliance. The contralateral premolar served as a control. The experimental periods varied from 1 to 7 weeks with eight children in each group. Root resorption was registered after 1 week and occurred in all test teeth but four. The surface extension as well as the depth of the resorption showed a marked increase after 2 weeks. Starting from the third week, eight test teeth exhibited apical root resorption that had reached half way to the pulp, or more. After 7 weeks, the test teeth showed on average more than 20 times larger mean resorbed root contour than the control teeth. Individual variations were considerable regarding both extension and depth of root resorption within each test group and were not correlated to the magnitude of tooth movement achieved. The radiographs failed to reveal any adverse tissue reactions. The great individual variations in root resorption without association to the amount of tooth displacement indicate that so far unknown individual factors are influential in these adverse tissue reactions.
The aim of this study was to evaluate the effect of sodium hypochlorite (NaOCl) solutions (3%, 5%) and saturated calcium hydroxide (Ca(OH)2) solution, individually and consecutively, on the flexural strength and modulus of elasticity of standardized dentine bars.
Standardized plano-parallel dentine bars (n = 121) were divided into five test groups and one control group. The control group 1 consisted of dentine bars, stored in normal saline until testing. The dentine bars in the five test groups were treated by exposure to the following solutions; group 2--3% NaOCl, 2 h; group 3--5% NaOCl, 2 h; group 4--saturated Ca(OH)2 solution, 1 week; group 5--3% NaOCl, 2 h and then saturated Ca(OH)2 solution 1 week; group 6--5% NaOCl, 2 h and then saturated Ca(OH)2 solution 1 week. The dentine bars were then loaded to failure in a three-point bend test.
The data revealed a significant (P < 0.001) decrease in the modulus of elasticity and flexural strength of the dentine bars treated with 3% and 5% NaOCl. There was no significant difference in the flexural strength and the modulus of elasticity between the 3% and 5% NaOCl groups. Exposure to Ca(OH)2 significantly (P < 0.001) reduced the flexural strength but had no significant effect on the modulus of elasticity. The groups treated with sodium hypochlorite followed by calcium hydroxide did not have moduli of elasticity and flexural strengths that were significantly different from those treated only with sodium hypochlorite.
NaOCl (3 & 5%) reduced the modulus of elasticity and flexural strength of dentine. Saturated Ca(OH)2 reduced the flexural strength of dentine but not the modulus of elasticity. Sequential use of NaOCl and Ca(OH)2 has no additional weakening effect.
Over the past 10 years, orthodontically induced inflammatory root resorption (OIIRR) has been increasingly recognized as an iatrogenic consequence of orthodontic treatment. With this in mind, orthodontists should take all known measures to reduce the occurrence of OIIRR. The evidence that we present in this review suggests several procedures known today that can avert this phenomenon; however, none of them can be relied on to completely prevent OIIRR. We believe that future studies might clarify the exact cause and course of OIIRR and, hopefully, help eliminate it. In Part I, we discussed the basic sciences aspects of OIIRR; in Part II, we present the clinical aspects of this phenomenon.
It has been proposed (Cvek 1992) that immature teeth are weakened by filling of the root canals with calcium hydroxide dressing and gutta-percha. The aim of the present study was to test the hypothesis that dentin in contact with calcium hydroxide would show a reduction in fracture strength after a certain period of time. Immature mandibular incisors from sheep were extracted and divided into two experimental groups. Group 1: the pulps were extirpated via the apical foramen. The root canals were then filled with calcium hydroxide (Calasept) and sealed with IRM(R) cement, and the teeth were then stored in saline at room temperature for 0.5, 1, 2, 3, 6, 9, or 12 months. Group 2: the pulps were extirpated and the root canals were filled with saline and sealed with IRM(R) cement. The teeth were then stored in saline for 2 months. Intact teeth served as controls and were tested immediately after extraction. All teeth were tested for fracture strength in an Instron testing machine at the indicated observation periods. The results showed a markedly decrease in fracture strength with increasing storage time for group 1 (calcium hydroxide dressing). The results indicate that the fracture strength of calcium hydroxide-filled immature teeth will be halved in about a year due to the root filling. The finding may explain the frequent reported fractures of immature teeth filled with calcium hydroxide for extended periods.
This study was carried out in order to observe the effectiveness of apexification in young permanent incisors. The sample comprised 26 young permanent incisors with necrotic pulp and open apices. The time taken to obtain apical closure, its form and size were analysed in order to find out if closure was influenced by existing pathology or size of apex. The treated teeth were compared with their corresponding contralateral teeth. The test of McNemar and anova was used and a result of P = 0.05 was considered significant. Teeth with pretreatment apical shapes that were convergent or parallel all resulted in physiological apical shapes after treatment. Eight teeth had divergent apical shapes before treatment. Of these, one had a physiological shape, five ended with rounded apices and two teeth had straight apices post-treatment. Apical closure was obtained in 100% of the cases studied, of these 88.4% needed three to four sessions of calcium hydroxide treatment (an average of 3.23 sessions) in order to obtain apical closure, the average time employed was 12.19 months. Clinical symptoms resolved in all teeth that presented with symptoms. Preoperative symptoms did not affect outcome. Pathology of the tooth before treatment does not influence the time needed to obtain apical closure.