Population specificity in mandibular sexual dimorphism: validation and development of forensic models for application in the contemporary Malaysian population

INTRODUCTION: Sex estimation is a critical part of the forensic anthropological assessment. The mandible, due to its robust nature and sexually dimorphic traits, is often a alternative region for sex estimation, particularly in cases where other skeletal are incomplete or absent. Population-specific studies are necessary to refine and enhance the accuracy of forensic methodologies. This study, therefore, aims to quantify mandibular sexual dimorphism and explore population variances, validate existing discriminant functions, and develop novel models for sex estimation specific to the Malaysian population. METHODOLOGY: The sample comprised cranial multi-detector computed tomographic scans of 213 male and 202 female Malaysian individuals. Following 3D volume rendering, nine mandibular landmarks were acquired using OsiriX, from which a total of 10 linear inter-landmark and one angular measurement were calculated. The data were then analysed using descriptive statistics and discriminant function analyses employing jackknife validations of classification results. RESULTS: All measurements were sexually dimorphic except for the mandibular angle. Bi-condylar breadth, ramus height, maximum mandibular length, and bi-coronoid breadth were the most dimorphic. Application of foreign discriminant functions to the Malaysian sample resulted in reduced accuracy and a greater sex bias compared to the original studies. The Malaysian specific univariate and multivariate discriminant functions ranged from 62.7 to 83.60% classification accuracy with associated 0.06 to -5.01% sex bias values. CONCLUSION: The findings emphasize the importance of validating and developing population-specific mandibular models for accurate sex estimation in the contemporary Malaysian population, while future research should expand multi-ethnic datasets to further enhance forensic identification reliability.