Sexual dimorphism in mental foramen position: A discriminant function study in the Malay population

The mandible has emerged as a pivotal structure for sex estimation in forensic contexts due to its exceptional postmortem preservation and pronounced sex-linked morphological variation. Among the anatomical landmarks on the mandible, the mental foramen has garnered significant attention due to its metric consistency and resistance to age-related resorption, making it an ideal candidate for population-specific morphometric analyses. This study aimed to rigorously evaluate sexual dimorphism in the spatial relationship between the mental foramen and mandibular lower border within the Malay population by applying advanced discriminant function analysis to derive a high-specificity forensic sex estimation tool.

A retrospective cohort study was conducted using 141 high-resolution digital orthopantomograms from the Malay population comprising 71 females and 70 males, thereby ensuring a nearly equal sex distribution for discriminant function analysis. Linear distances from the superior (S-L) and inferior (I-L) borders of the mental foramen to the mandibular lower border were measured bilaterally. Discriminant function analysis was conducted to develop a sex classification model, which was validated based on cross-validation and comparative statistical metrics.

Significant sexual dimorphism was observed across all measurements (p < 0.001), where males had larger mean distances compared with females. The derived discriminant function achieved a classification accuracy of 75.18 %, where the left I-L had the highest discriminatory power (standardized coefficient = 0.488). Canonical correlation analysis (0.523) and Wilks' lambda (0.726) confirmed the model's robustness.

In this study, the first population-specific discriminant equation for sex estimation in Malays was established, addressing a critical gap in forensic anthropology. The findings highlight the need for ethnic-specific morphometric standards, and provide a reproducible tool for forensic applications.