Usability of the mandibular gonial angle measured retrospectively from computed tomography sections in sex estimation

Sex estimation is a crucial step in the identification process. This study investigates the forensic potential of the mandibular gonial angle measured on computed tomography (CT) scans for sex estimation. In our study, cranial and maxillofacial images were randomly selected from computed tomography scans with appropriate imaging quality. Cases with maxillofacial morphological deformity, nonadult cases, foreign bodies or motion artifact in radiological images, or a history of surgical intervention due to maxillofacial trauma were excluded. 240 males and 240 females subjects were included in the study. Participants were categorized into three age groups (20–39, 40–59, and 60–80 years) to compare sex-related differences. Statistical analysis was conducted using a two-way fixed-effects ANOVA to evaluate the effects of sex, age group and their interaction on gonial angle measurements. Normality of distributions was confirmed by the Shapiro-Wilk test (p > 0.05) and homogeneity of variances was verified by Levene's test (p > 0.05). The ANOVA revealed statistically significant main effects for sex (p < 0.001) and age group (p = 0.001) as well as a significant interaction effect (p = 0.048). Effect sizes were calculated using partial eta squared, showing a moderate effect for sex (η² = 0.061) and small effects for age group (η² = 0.029) and the interaction (η² = 0.013). Post-hoc pairwise comparisons were performed using Tukey's HSD test. Our findings indicate that female gonial angles are consistently larger than those of males across all age groups. This angular variation as observed in our analysis tends to increase with age. It was also concluded that this increase starts to show statistically significant sexual dimorphism after the age of 40 and that it becomes more dimorphic between the ages of 60–80.