Assessment of Age at the Stages of the Eruption of Third Molar Teeth among the People of North-Eastern India

Background and Objectives. In the biological age determination of a person’s teeth at adolescence, the third molar (M3) or wisdom tooth development is considered a dependable method used over the years. The present research intended to evaluate the age from the eruption status of M3 and analyze and equivalence with a different quadrant of the jaws. Methods. A cross-sectional descriptive and analytical study was undertaken with 1060 Assamese individuals (642 males and 418 females) aged 14–26 years and was subjected to a clinical, dental, and general physical examination from January 2014 to December 2018. The data were statistically analyzed using Microsoft Excel and the Statistical Package for the Social Sciences (SPSS) version 22. The significant differences among variables were tested using the chi-square test and Student’s t -test, considering a p value < 0.05 as significant. Results. The carried-out research showed no eruption (NE) status of M3 with an overall mean (±SD) age at 17.39 (±2.273) years, although a significantly lower age among males with a mean age of 16.92 (±2.138) years ( p value < 0.001) was observed. The mean age (overall) for the complete eruption (CE) was observed at 20.33 (±2.566) years, which was seen earlier in males. The mandibular M3 appears earlier compared to the maxillary M3. The third molar eruption (TME) on both left and right quadrants of the jaw was observed substantially earlier in the lower jaw, compared to the upper jaw ( p value < 0.025). The earliest CE of M3 was marked at 15 years. The differences in the frequencies of TME in different chronological age groups were found significant ( p value < 0.001). A significant association between gender and TME ( p value < 0.045) in the current study is worth noting. Conclusion. Thus, determined by TME as a valid method, age can be used for various purposes to establish a person’s identity. Dental age estimated using third molar eruption status has a weighty association with chronological age. Thus, it should be utilized to determine the likely age of an individual.

Should Degree of Third Molar Eruption Influence Operative Management of Mandibular Angle Fractures? A Systematic Review

Objective There is a growing trend toward evidence-based management of third molars in the fracture line of mandibular angle fractures (MAFs). This study aimed to differentiate MAF fixation complications by degree of third molar eruption and by extraction strategy in patients undergoing Champy fixation. Methods PubMed, EMBASE, OVID, SCOPUS, the Cochrane Library, and clinicaltrials.gov were queried through May 2020 for English-language publications for MAFs with third molar involvement for this systematic review. Bias was assessed using author-defined criteria. Relative risk (RR) of post-operative complications associated with extracted unerupted and retained partially erupted third molars (Group I) was calculated against controls of retained unerupted and extracted partially erupted third molars (Group II). Results Ten studies reported complications by eruption or extraction; however, only one study stratified complications by both eruption and extraction to meet inclusion criteria. The risk of bias was medium as only cases meeting defined follow-up were included. 73 cases (N) were included: 34 qualified for Group I and 39 for Group II. Quantitative synthesis of individual case data demonstrated significantly higher complication rate in Group I compared to Group II (23.5% vs 5.1%) (RR 4.6, 95% CI 1.04–20.1). No significant differences were observed between groups for infectious complications, mechanical complications, nonunion, or dehiscence. Reoperation was required significantly more often for Group I ( P = .043). Conclusions For MAFs involving the third molar, concomitant extraction of unerupted as well as retention of partially erupted third molars increases risk of complications with Champy fixation technique. For these patients, alternative strategies for fixation should be considered.

Midfacial development and the wisdom of teeth: A case series

The alignment of third molars has largely been overlooked by orthodontists. Since difficulties arise during their eruption, a plethora of surgical procedures is advocated for their management, including prophylactic extraction. This case series describes the use of midfacial development in 4 patients and illustrates successful patterns of third molar eruption.

The Frequency of Mandibular Third Molar Impaction in Different Types of Vertical Skeletal Faces

OBJECTIVE: To determine the frequency of mandibular third molar impaction in different vertical skeletal facial types. METHODOLOGY: Data was collected using pre-treatment records including orthodontic files, pre-treatment lateral cephalograms and OPGs of 90 orthodontic patients. Patients from both genders were included. The age group of selected patients was 18-30 years. Vertical skeletal malocclusion was measured using facial angle and mandibular plane angle on cephalogram to group the subjects into Mesiofacial, Brachyfacial and Dolichofacial patients. Third molar eruption status was assessed using OPG. RESULTS: Results showed that erupted third molars were mostly found in brachyfacial patients. Among 32 erupted mandibular third molars, 16 belong to brachyfacial, 11 belonged to mesiofacial and 5 belonged to dolichofacial group. Complete impaction of mandibular third molar was most common among dolichofacial patients. Among 29 completely impacted mandibular third molars, 14 belong to dolichofacial, 9 belonged to mesiofacial and 6 belonged to brachyfacial group. No significant difference was found for partially impacted third molars among the three groups of facial types. There was higher prevalence of mandibular third molar impaction in females as compared to males. CONCLUSION: Frequency of third molar impaction was found to be highest in dolichofacial patients and lowest in brachyfacial patients due to forward direction of mandibular growth contributing to greater resorption of the anterior border of ramus and the additional space required for third molar eruption.

Effect of Genetic and Environmental Factors on the Impaction of Lower Third Molars

The aim of this retrospective study was to evaluate the impact of genetic and environmental factors on the impaction of lower third molars using a classical twin study by evaluation of the third molar eruption space and M3 angulation. The study group consisted of 212 twins: 80 dizygotic and 132 monozygotic twins with digital panoramic radiograms and lateral cephalograms. The zygosity of twins was determined using 15 highly polymorphic DNA regions from the venous blood of twins. The results showed that differences between siblings in the dizygotic and monozygotic twin pairs were not statistically significant. The most fitting model for the angulations of lower third molars was AE (additive genetic and specific environmental effect), where the additive genetic factors had up to 88% influence and the specific environment up to 27%. Therefore, the ACE( additive genetic, common and specific environmental effect), model showed higher significance for the lower third molar eruption level where additive genetic estimates reached 71%, a specific environment contributed up to 15% and the common environment reached 32%. The conclusion was that a considerable proportion of the third molar impaction could be attributed to additive genetic effects and the common environment, whereas the specific environment had a lower, but significant impact.

Artificial Intelligence (AI)-Driven Molar Angulation Measurements to Predict Third Molar Eruption on Panoramic Radiographs

The purpose of the presented Artificial Intelligence (AI)-tool was to automatically segment the mandibular molars on panoramic radiographs and extract the molar orientations in order to predict the third molars’ eruption potential. In total, 838 panoramic radiographs were used for training (n = 588) and validation (n = 250) of the network. A fully convolutional neural network with ResNet-101 backbone jointly predicted the molar segmentation maps and an estimate of the orientation lines, which was then iteratively refined by regression on the mesial and distal sides of the segmentation contours. Accuracy was quantified as the fraction of correct angulations (with predefined error intervals) compared to human reference measurements. Performance differences between the network and reference measurements were visually assessed using Bland−Altman plots. The quantitative analysis for automatic molar segmentation resulted in mean IoUs approximating 90%. Mean Hausdorff distances were lowest for first and second molars. The network angulation measurements reached accuracies of 79.7% [−2.5°; 2.5°] and 98.1% [−5°; 5°], combined with a clinically significant reduction in user-time of >53%. In conclusion, this study validated a new and unique AI-driven tool for fast, accurate, and consistent automated measurement of molar angulations on panoramic radiographs. Complementing the dental practitioner with accurate AI-tools will facilitate and optimize dental care and synergistically lead to ever-increasing diagnostic accuracies.

Orthodontic treatment with passive eruption and mesialization of semi-impacted mandibular third molar in an adult with multiple dental losses

ABSTRACT Objective: This article describes the orthodontic treatment performed on an adult patient with multiple dental losses. Case report: A female patient, 20 years and 4 months old, presented with the following conditions: absence of teeth #26, #35, #36 and #46; semi-impacted tooth #48; inclined molars adjacent to an edentulous space; canines and premolars in a Class II relationship; a convex profile; biprotrusion; and forced lip sealing. Results: Space in the region of tooth #26 was closed, as well the space of tooth #46; tooth #48 erupted and followed mesial movement passively; space of the region of tooth #35 was maintained for the placement of a dental implant; uprighting of tooth #37 was obtained. Aesthetic and functional goals of the treatment were achieved. Results remained stable 10 years after the end of the treatment. Conclusion: The modified helical loop could be effectively used in orthodontic mechanics to close edentulous spaces. Passive semi-impacted mandibular third molar eruption and mesialization can occur in adults when proper space is provided.