Sexual Dimorphism or Statistical Overlap? Diagnostic Evaluation of the Gonial Angle for Gender Determination - An Anthropometric Approach

Abstract Background Sex estimation is a critical step in forensic human identification. The mandible, owing to its structural resilience and morphological variation between sexes, has been widely studied for gender determination. Among its parameters, the gonial angle has been proposed as a potential radiomorphometric indicator; however, population-specific validation remains limited in the Tamil Nadu population. Aim To evaluate the reliability and predictive accuracy of the gonial angle for gender determination using digital orthopantomograms in a South Indian population. Materials and Methods A retrospective cross-sectional study was conducted on 158 digital panoramic radiographs comprising 79 males and 79 females aged 20–30 years. Bilateral gonial angles were measured using Planmeca Romexis software. Gender differences were assessed using the Mann–Whitney U test. Diagnostic performance was evaluated using Receiver Operating Characteristic (ROC) curve analysis, and binary logistic regression analysis was performed to assess predictive accuracy. Statistical significance was set at p < 0.05. Results The mean gonial angle was 127.78° ± 9.15 in males and 125.42° ± 6.21 in females. The difference was not statistically significant (p = 0.059). ROC analysis demonstrated poor discriminatory ability (AUC = 0.413; 95% CI: 0.324–0.502). The optimal cut-off value (125.48°) yielded sensitivity of 50.6% and specificity of 40.5%. Logistic regression analysis did not show gonial angle to be a significant predictor of gender (p = 0.093). Overall classification accuracy was 56.3%. Conclusion Within the studied Tamil Nadu population, gonial angle alone demonstrated limited predictive value for gender determination. It may serve as an adjunctive parameter when combined with other mandibular measurements in multivariate models.