Effect of impaction on third molar development and age estimation-A study in a Lebanese population.

BACKGROUND: The effect of impaction on third molar development is disputable as the scientific literature is not uniform. In parallel, population-specific studies have been encouraged in dental age estimation. This study aimed to investigate the effect of impaction on third molar formation in a sample of Lebanese individuals. MATERIALS AND METHODS: The sample consisted of 518 panoramic radiographs of females (n=229) and males (n=289) between 15 and 23.9 years. Mandibular third molars were classified based on their position as non-impacted and impacted (with horizontal, vertical, mesioangular, and distoangular impaction). Dental development was classified according to Demirjian's 8-level staging system. RESULTS: Most teeth presented mesioangular impaction (#38=29.7%, #48=33%). Developing third molars were predominantly distributed between stages D and G. The mean age of most developmental stages was higher among impacted teeth, meaning that third molar mineralization could be slower in the presence of impaction. In general, the delayed dental development did not have statistically significant effects (P<0.05). However, descriptive data pointed out differences between (impacted and non-impacted) mean ages of >12 months-suggesting a potential clinical significance (despite the lack of a statistical one). Furthermore, differences changed based on sex and side (#38/#48). CONCLUSION: Therefore, dental age estimation from third molars in the selected Lebanese population should preferably be performed in non-impacted third molars whenever available.

Ear identification: A multi-ethnic study sample.

The external human ear is considered to be highly variable among individuals. Hence, forensic applications could be explored for human identification. This research compares the usefulness of Cameriere's ear identification method, in samples originating from six different countries (Brazil, India, Japan, Russia, South Africa and Turkey) in order to examine possible differences in their accuracy values. A sample of 2,225 photographs of the external human ear (1,134 left and 1,091 right ears) from 1,411 individuals (633 females and 778 males) was collected. The samples included healthy subjects with no systemic disorders and without any craniofacial trauma, maxillofacial abnormalities, auricular anomalies, ear diseases or previous auricular surgery. Cameriere's ear identification method was applied and measurements were performed on the images of each ear, considering four anatomic regions: helix, antihelix, concha, and lobe. The quantified measurement values were converted into a proposed coded number system. A search for identical codes was accomplished to find out the distinctiveness of the morphology of the human ear. The combined codes of left and right ears of each of the 814 subjects were not repeated in this multi-ethnic study sample. Dirichlet's distribution and the inherent study equation showed that the probability of two different individuals having the same code (false-positive identification) was found to be <0.0007. Because of the distinctive metrics of the ratios of external human ears, studies with Cameriere's ear identification method may be valuable for human identification. Studying the differences between the left and right ears of the same individual and across different ethnic groups could contribute to the development of supplementary tools for human identification.

Validation of radiographic visibility of root pulp in mandibular first, second and third molars in the prediction of 21 years in a sample of south Indian population: A digital panoramic radiographic study.

This study examines the radiographic visibility of root pulp (RPV) in lower first, second and third molars to validate the completion of 21 years. RPV in all lower three molars of both sides was assessed using a sample of 930 orthopantomograms of individuals aged between 15 and 30. The scoring of RPV was done using the Olze et al. four-stage classification (Int J Legal Med 124(3):183-186, 2010). Cut-off values were determined for each molar using the receiver operating characteristic (ROC) curve and the area under the ROC curve (AUC). The selected cut-off values were stage 3 for the first molar, stage 2 for the second molar and stage 1 for the third molar. For lower first molar, the AUC was 0.702, and the sensitivity, specificity and posttest probability (PTP) were 60.1%, 98.8% and 98.1% in males, and 64.5%, 99.1% and 98.6% in females. For lower second molar, the AUC was 0.828, and the sensitivity, specificity and PTP were 75.5%, 97% and 96.2% in males, and 74.4%, 96.3% and 95.3% in females. For the lower third molar, the AUC was 0.906; the sensitivity was 74.1% and 64.4% in males and females, while specificity and PTP were 100% in both sexes. The accuracy of predictions for the completion of 21 years was high. However, the greater percentage of false negatives and inapplicability of this method in one-third of lower-third molars have been recommended for using this method in conjunction with other dental or skeletal methods.

Radiographic evaluation of secondary dentin formation in lower premolars for forensic age diagnosis of 18 years in a sample of south Indian adolescents and young adults.

There has been an increase in the need for alternate methods of dental age assessment, especially for the forensic age diagnosis of the 18th year of life. This is due to the completion of the third molar development before 18 years or the agenesis or therapeutic extractions of the third molars. The present study aimed to verify whether the secondary dentin formation in lower premolars can be used to determine the completion of the 18th year of life in a sample of South Indian adolescents and young adults. For this purpose, 800 orthopantomograms of 400 male and 400 female South Indian subjects aged 14- 22 were evaluated. The characteristics of the secondary dentin formation were determined in all mandibular premolars using the stage classification according to Olze et al (Int J Legal Med 126(4):615-21). The results showed that when stage 3 of secondary dentin formation was reached in the first premolars, the probability of the subject completing the 18th year of life was very high. However, only a few individuals in the studied population were at stage 3. Therefore, proceeding cautiously with this degenerative change in lower premolars is advised due to the higher inter-examiner differences. It is also recommended to use this method in conjunction with other age estimation methods. Further research should investigate other degenerative characteristics in the studied population.

Testing the maturation and the radiographic visibility of the root pulp of mandibular third molars for predicting 21 years. A digital panoramic radiographic study in emerging adults of south Indian origin.

Prediction of the attainment of legal age thresholds, especially in children and young adults, is a common task in medico-legal practice. In many countries, 21 years has medico-legal importance. In the present study, we assessed and compared the accuracy of the third molar maturity index (I3M) and the stages of radiographic visibility of the root pulp (RPV) in predicting the age threshold of 21 years. A sample of 910 digital panoramic radiographs (455 males and 455 females) of adolescents and young adults aged between 16 and 30 of south Indian origin were evaluated. The authors examined the performance of different I3M cut-off values and RPV stages. I3M cut-off value of 0.02 has resulted in better discrimination with an accuracy of 76.92% and 80.44%, specificity of 48.28% and 56.16% in males and females, a sensitivity of 100%, and post-test probability of 65.9% in both sexes. The accuracy and sensitivity of RPV stage 2 were 84.76% and 84.55%, 78.17%, and 78.97% in males and females, while the specificity and post-test probability were 100% in both sexes. In conclusion, the I3M method resulted in a more significant percentage of false positives and cannot be used to state the attainment of 21 years. However, the presence of RPV stage 2 could say that the subject had already attained the age of 21 years. Further studies are warranted to address the usefulness of these methods.

Can root pulp visibility in mandibular first molars be used as an alternative age marker at the 16 year threshold in the absence of mandibular third molars: an orthopantomographic study in a South Indian sample.

In many countries, the 16 years of age threshold is considered to be legally relevant according to the law. This research aims to ascertain the sensitivity and specificity of Olze et al. stages of root pulp visibility (RPV) in a sample of 760 south Indian children aged between 12 and 20 years, with an age threshold of 16 years, using receiver operating characteristic curves and area under the curve (AUC). Spearman's rho correlation showed a strong positive correlation between the RPV stages and age. No significant difference between the right and left lower first molars was seen. RPV Stage 2 showed the highest AUC in both females (0.813) and males (0.790). The performance of the RPV Stage 2 to discriminate the legal age threshold of 16 years resulted in the sensitivity, specificity and accuracy values of 0.61, 0.96 and 0.77 in males, 0.65, 0.97 and 0.80 in females. It resulted in 3.6% and 2.9% of false positives and 38.5% and 34.5% of false negatives in both sexes. Even though, RPV Stage 2 can discriminate reasonably well between two age categories, due to the high percentage of false negatives we recommend its use in conjunction with other age estimation methods.

Comparison of the third molar maturity index (I3M) between left and right lower third molars to assess the age of majority: a multi-ethnic study sample.

The diagnostic accuracy of the I3M to assess the legal age of 18 years has already been tested in several specific-population samples. The left lower third molar has been extensively used for discriminating between minors and adults. This research aimed to compare the usefulness of lower third molar maturity indexes, from both left and right side (I3ML and I3MR), in samples originating from four distinct continents in order to examine possible differences in their accuracy values. For this purpose, a sample of 10,181 orthopantomograms (OPGs), from Europe, Africa, Asia and America, was analysed and previously scored in other studies. The samples included healthy subjects with no systemic disorders with both third molars and clear depicted root apices. Wilcoxon Signed Rank test for left and right asymmetry did not show any significant differences. Data about sensitivity, specificity, predictive values, likelihood ratio and accuracy were pooled together and showed similar results for I3ML and I3MR, respectively. In addition, all these quantities were high when only the I3MR was considered to discriminate between adults and minors. The present referable database was the first to pool third molar measurements using panoramic radiographs of subjects coming from different continents. The results highlighted that both I3ML and I3MR are reliable indicators for assessing the legal age of 18 years old in those jurisdictions where this legal threshold has been set as the age of majority.

Assessing the probability of having attained 16 years of age in juveniles using third molar development in a sample of South Indian population.

Juvenile crime or delinquency has been increasing at an alarming rate in recent times. In many countries, including India, the minimum age for criminal responsibility is 16 years. The present study aimed to estimate the probability of a south Indian adolescent either being or being older than the legally relevant age of 16 years using Demirjian's tooth formation stages. Orthopantomograms (OPG) of 640 south Indian adolescents (320 boys and 320 girls) aged between 12 and 20 years were retrospectively analyzed. In each OPG, Demirjian's formation stage of the mandibular left third molar was recorded and the data was subjected to statistical analysis. Descriptive and Pearsons correlation statistics were performed. The empirical probabilities were provided relative to the medico-legal question of predicting 16 years of age. The distribution of age throughout the 10th, 25th, 50th, 75th and 90th percentile follows a logical distribution pattern horizontally and vertically. Pearson's correlation statistics showed a strong positive correlation between the Demirjian's stages and age for both sexes. Therefore, it can be concluded that stage "F" can be used to predict the attainment of age equal to or older than 16 years with a probability of 93.9% for boys and 96.6% for girls.

Accuracy of four dental age estimation methods in determining the legal age threshold of 18 years among South Indian adolescents and young.

The aim of this study was to compare the accuracy, specificity and sensitivity of four commonly used methods of dental age estimation in a sample of south Indian adolescents and young adults aged between 14 and 30 years, with an age threshold of 18 years, using receiver operating characteristic curves (ROC) and the area under the curve (AUC). A total of 1070 orthopantomograms (535 males and 535 females) of adolescents and young adults of south Indian origin were collected retrospectively and interpreted. The effectiveness of each method was evaluated by using sensitivity (Se), specificity (Sp), likelihood ratios (LR+ and LR-) and AUC. Among all methods, I3M< 0.08 resulted in better values of AUC, Se and Sp which were 0.950, 91.5%, 97.8% and 0.950, 88.5% and 98.6% in males and females, respectively. For "stage H" of Demirjian's system, the AUC, Se and Sp were 0.940, 84.9%, 97.7% and 0.930, 79.9% and 98.5% in males and females, respectively. The use of the Olze et al "stage 1 (or higher)" root pulp visibility and "stage D" of third molar eruption were not recommended in the studied population due to the greater percentage of third molars with incomplete mineralization in younger age groups and impaction. Taking into account the values of Se, Sp, both positive and negative LRs, we recommend the use of the cut-off value of I3M< 0.08 to discriminate adults and minors in south Indian adolescents and young adults.

Testing the accuracy of Bedek et al's new models based on 1-to-7 mandibular teeth for age estimation in 7-15 year old south Indian children.

The goal of long term research on age assessment is to focus on the strengths and weaknesses of existing reliable methods of age estimation. In cases of age estimation when all teeth are present, maximum accuracy can be obtained using a 7 tooth model. Demirjian's system and Willems models require all seven mandibular teeth in the lower left quadrant for age assessment. Unfortunately, these methods cannot be applied in children with hypodontia. In 2019, Bedek et al., from Croatia, developed new models of age estimation based on a combination of one to seven mandibular teeth. In the present study, we tested the accuracy of the newly developed models for age estimation in South Indian children. Tested in parallel with Willems models, the accuracy of the new models was tested in terms of mean difference, mean absolute error (MAE) and percentage of correct estimations within intervals of +0.5 and +1 years. In terms of mean difference between chronological age (CA) and estimated dental age (DA), all models along with Willems models have underestimated the CA except Bedek et al's 6 tooth model where overestimation of CA was seen in boys. For MAE and percentage of correct estimations, the new models performed better than Willems models. With regards to our results, it can be concluded that the new models for dental age calculation are accurate and suitable. Therefore, we may encourage their use for age estimation in South Indian children, particularly in individuals with hypodontia or when multiple teeth are missing.