Geometric morphometric analysis of mandibular morphology for age classification in Indonesian adolescents and adults

Accurate age estimation plays a crucial role in medicolegal investigations, particularly in determining whether an individual has reached the age of majority for criminal responsibility, which is legally defined as 18 years in Indonesia. Geometric morphometric (GM) analysis of the mandible enables the evaluation of shape variability in two-dimensional (2D) data with potential applications in categorizing individual ages. Purpose: This study aimed to evaluate the applicability of geometric morphometric (GM) analysis of mandibular morphology on panoramic radiographs for classifying individuals as adolescents or adults.

300 digital panoramic radiographs were obtained from Airlangga University Dental Hospital in Surabaya and divided into adolescent (15.0-17.9 years) and adult (18.0-21.0 years) age groups. Each sample was assigned 27 anatomical landmarks and analyzed using MorphoJ software with generalized Procrustes analysis (GPA) and principal component analysis (PCA), while statistical evaluation included Procrustes analysis of variance (ANOVA) and discriminant function analysis (DFA).

GM analysis revealed statistically significant differences in mandibular morphology between adolescents and adults. However, Procrustes ANOVA did not show significant differences in mandibular size between the age groups. Variable mandibular morphology patterns were identified at the incisor point, mental foramen, gonion, and mandibular notch. The geometric morphometric method successfully identified the mandibular morphologies specific to each group, achieving 67 % and 65 % accuracy for the adult and adolescent groups, respectively.

These findings underscore the potential of GM analysis of mandibular morphology for classifying individuals as adolescents or adults.