Evaluating legal age of 18 years through observation of third molars using Gambier et al. method in an orthopantomographic sample of subadults from South India.

In forensic practice, medicolegal physicians are often tasked with estimating age using dental evidence. This calls for an uncomplicated, reliable, and reproducible method for dental age estimation, enabling physicians to proceed without specific odontological expertise. Among various dental methods, third molar eruption analyses are less complicated and easier to perform. In our study, we explored the effectiveness of Gambier et al.'s scoring system, which examines the eruption of all third molars. We retrospectively analysed 1032 orthopantomograms (528 males and 504 females) of individuals aged between 15 and 24 years. The mean chronological age increased with the progression of stages (1 to 3) and phases (A to D) of the third molar eruption for both sexes. In terms of stages, none showed significant discrimination between minors (<18 years) and adults (>18 years), especially for males. However, Gambier's phase D displayed a relatively high likelihood of being 18 years or older, with an overall 85.9 % of males and 95.7 % of females having all third molars in stage 3 being 18 years or older. While the tested method could be helpful in indicating the completion of the 18th year of life, caution is advised (due to a high percentage of false positives), and it should be used alongside other age assessment methods by experts.

Is there any difference in the development of mandibular third molars according to the type of impaction: An orthopantomographic study in south Indian children and adolescents.

Development of third molars and their influence on the dental arch is a major concern in clinical dentistry especially, orthodontics and oral surgery. Lately, their position, eruption potential and development has become a subject of interest in forensic practice. The present study was aimed to determine whether if there is any difference in the development of the mandibular third molars according to the impaction type. Orthopantomographs (n = 1112) from 478 males and 634 females between 15 and 22 years old were analysed. In each radiograph, impaction status and the developmental stage of mandibular third molars were determined. Descriptive statistics were performed at developmental stages D to H. For stage G, there was a delay by 0.74 and 0.62 years for mesioangular impaction, 0.89 and 0.33 years for horizontal impaction, 1.43 and 0.9 years for distoangular impaction and 1.74 and 1.1 years for vertical impaction, in males and females. For stage H, delay by 0.17 and 0.74 years, 0.05 and 0.06 years, 0.48 and 1.48 years and 0.62 and 0.62 years, respectively for all impaction variants in both sexes. Mean chronological age of the distoangular and vertically impacted mandibular third molars were higher in certain developmental stages than mesioangular and horizontal impactions. Our findings concluded that distoangular and vertical impaction variants mineralize more slowly than mesioangular and horizontal variants, however these differences were smaller. Therefore, no distinction is required between impaction types for dental age estimation especially in the prediction of the age of majority (18 years).

Legal age determined by a new threshold value of third molar maturity index in subjects with impacted mandibular third molars: An orthopantomographic study in south Indian adolescents.

Third molars are one of the few biological markers available for age estimation in juveniles, especially for the estimation of the 18-year-age threshold. Literature has indicated that impaction has an influence on the development of third molars, which could possibly result in age misclassifications. The present study is intended to identify an alternative cut-off value of the third molar maturity index (I3M) in impacted mandibular third molars and also to evaluate its applicability in estimating the major (≥ 18 years)/minor (< 18 years) status. A total of 1330 digital orthopantomograms (OPGs) of 665 male and 665 female south Indian adolescents aged from 15 to 22 years were collected and assessed. Eight hundred forty OPGs (63.1%) represented test sample, and 490 OPGs (36.9%) represented validation sample. I3M was measured for the total sample. Logistic regression, receiver operating characteristic (ROC) curve analysis, and Youden's index were used to test the performance of the method in the test sample. An alternative cut-off value of I3M < 0.17 was established for the highest value of the Youden's index of 0.598 for both sexes. When tested in validation sample, it has resulted in sensitivity and specificity values of 0.91 (95% CI; 0.86-0.95) and 0.90 (95% CI; 0.78-0.91) in males and 0.86 (95% CI; 0.80-0.92) and 0.90 (95% CI; 0.83-0.95) in females. In conclusion, cut-off value of I3M < 0.17 could accurately discriminate adults from minors with impacted mandibular third molars. However, more work is needed to be done among a more diverse sample to confirm these findings.