L’ankylose dentaire : diagnostic par tomodensitométrie et reconstruction tridimensionnelle

Forced eruption in impacted teeth: analysis of failed cases and outcome of re-operation

BACKGROUND

Forced eruption of an impacted tooth usually requires surgical and orthodontic interventions to successfully bring the tooth into the dental arch. The clinical time required for a forced eruption is difficult to predict before treatment begins and success rates are affected by several factors before and after an eruption. This study was conducted to identify factors that affect the success of forced eruption, the duration of orthodontic treatment of impacted teeth, and the reasons for re-operation and forced eruption failure in a various teeth and cases.

METHODS

In this retrospective study, the records regarding the forced eruption of 468 teeth in 371 patients from June 2006 to May 2020 at the Advanced General Dentistry Department of Yonsei University Dental Hospital were initially examined. The records of 214 teeth in 178 patients who completed orthodontic treatment were included in the analysis. Data on patient demographics, tooth characteristics, orthodontic treatment duration, re-operations, and failures were collected from electronic medical records.

RESULTS

There was a significant difference in age between the success and failure forced eruption. Factors significantly affecting treatment duration were apex formation, position, rotation, and re-operation. Re-operation had a 96% success rate. The average orthodontic treatment duration was 29.99 ± 16.93 months, but the average orthodontic treatment duration for teeth that undergone re-operation was 20.36 ± 11.05 months, which was approximately 9 months shorter. Additionally, there was an interaction effect between rotation and re-operation on the duration of orthodontic treatment. The causes for failure of forced eruption in 6 cases were ankyloses (3 cases), incomplete alignment with the normal dental arch (2 cases), and a significant deviation in the impacted tooth's location (1 case).

CONCLUSIONS

To increase the success rate of forced eruption, age should be considered as a priority, and in order to predict the treatment period, the apex formation status, position in the arch, and rotation should be considered in addition to age. When determining re-operation, considering factors such as ankylosis, root curvature, and apex formation can help in the success of orthodontic treatment.

Pixel gray measurement for the diagnosis of dental ankylosis in cone beam computed tomography images

OBJECTIVE

The aim of this study was to investigate dental ankylosis in unerupted or partially erupted teeth by using cone beam computed tomography (CBCT) to quantify pixel intensity.

STUDY DESIGN

In total, 157 CBCT images from individuals with a total of 206 unerupted or partially erupted teeth with suspected ankylosis were evaluated. CBCT images were analyzed for the presence of ankylosis by 2 oral radiologists by quantifying mean pixel intensities (analysis 1) and variations in pixel intensities (analysis 2) in normal and ankylosed regions. The association between ankylosis and demographic and tooth-related factors was also examined.

RESULTS

Ankylosis was diagnosed in 57 teeth (27.7%). The diagnosis was established with all 3 multiplanar reconstruction views in 22 of these teeth (38.6%). In analysis 1, a higher pixel intensity was observed in areas with ankylosis compared with normal periodontal ligament (PDL) density as a result of bone deposition in this region, which is characteristic of ankylosis (P < .001). In analysis 2, reductions in pixel intensity were greater in the PDL areas than in the ankylosed areas. Ankylosis was significantly associated with the anterior teeth, the maxillary arch, single-rooted teeth, and impacted teeth (P ≤ .026).

CONCLUSIONS

Our results suggest that CBCT measurement of pixel intensity may be useful for the diagnosis of ankylosis.

[Diagnosis and management of ankylosed permanent maxillary incisors: proposal for a decision tree]

INTRODUCTION

Ankylosis of a maxillary incisor involves evolutive resorption for which clinical management is difficult for both general practitioners and orthodontists. This anomaly can give rise to potentially major aesthetic, functional and occlusal defects. The ankylosed tooth will be lost, in the short or long term, depending on the bone remodeling.

MATERIALS AND METHODS

The aim of this review was to determine the different therapeutic options known to date and allow the construction of several clinical decision support systems (summary tables and decision tree).

RESULTS

The different techniques were classified in three categories: abstention, conservative treatments and surgical treatments. The therapeutic objectives, indications and potential complications were listed for each technique. The possible persistence of an ankylotic zone or the ability to move the tooth after treatment was also recorded.

DISCUSSION

The therapeutic solution is decided on after a precise diagnosis in order to evaluate the extent of the resorption and its localization. The chosen treatment will be more or less stable, conservative, aesthetic and expensive, and will have varying success rates. The time component must be taken into account and an individualised diagnosis and treatment plan are necessary to select the most appropriate therapeutic option for patients.

[Reason for failure in the treatment of impacted and retained teeth]

The positioning of an impacted or retained tooth in either children or adults presents a real challenge for the two practitioners involved, the orthodontist and the surgeon in charge of the surgical exposure. The maxillary canine is the tooth most often impacted in the anterior segment, with a prevalence of 2% in the general population. One can understand, therefore, the functional and esthetic challenge for the surgical-orthodontic team whose aim will be to reposition the impacted or retained tooth in the arch. A large number of mistakes must be avoided in order to achieve a satisfactory result for both the patient and the practitioner. Modern imaging techniques should be used to obtain a precise diagnosis of the location of the tooth and to perform surgery which will spare the tooth in question as well as the surrounding anatomic structures. The directions and forces of the traction used will need to be carefully thought out in order to move the tooth into its final position on the arch in optimal conditions. The periodontal setting will be optimized and checked at every step of the treatment. The aim, in fact, is to anticipate the onset of periodontal problems on the grounds that prevention is easier than cure.

Restoration of a vertical alveolar bone defect by orthodontic relocation of a mesially impacted mandibular first molar

An impacted mandibular first molar tends to cause serious bone defects of the adjacent teeth. When choosing between the 2 typical treatment options-extraction or orthodontic relocation of the impacted tooth-the decision should be based on assessment of the prognosis. A 22-year-old man with severe mesioangulation and impaction of the mandibular first molar and a related vertical bone defect on the distal side of the second premolar was treated with extraction of the second molar and orthodontic relocation of the first molar with a retromolar miniscrew. Comprehensive orthodontic treatment involving premolar extraction was conducted. Strategic extraction of the molar and adequate orthodontic movement helped to restore the bone structure on the affected side. This case report suggests the effectiveness of restoration of bone defects by using viable periodontal tissues around the impacted tooth for the longevity of the periodontium.

Application of Bayesian classifier for the diagnosis of dental pain

Toothache is the most common symptom encountered in dental practice. It is subjective and hence, there is a possibility of under or over diagnosis of oral pathologies where patients present with only toothache. Addressing the issue, the paper proposes a methodology to develop a Bayesian classifier for diagnosing some common dental diseases (D = 10) using a set of 14 pain parameters (P = 14). A questionnaire is developed using these variables and filled up by ten dentists (n = 10) with various levels of expertise. Each questionnaire is consisted of 40 real-world cases. Total 14*10*10 combinations of data are hence collected. The reliability of the data (P and D sets) has been tested by measuring (Cronbach's alpha). One-way ANOVA has been used to note the intra and intergroup mean differences. Multiple linear regressions are used for extracting the significant predictors among P and D sets as well as finding the goodness of the model fit. A naïve Bayesian classifier (NBC) is then designed initially that predicts either presence/absence of diseases given a set of pain parameters. The most informative and highest quality datasheet is used for training of NBC and the remaining sheets are used for testing the performance of the classifier. Hill climbing algorithm is used to design a Learned Bayes' classifier (LBC), which learns the conditional probability table (CPT) entries optimally. The developed LBC showed an average accuracy of 72%, which is clinically encouraging to the dentists.