Sex and age biological variation of the mandible in a Portuguese population- a forensic and medico-legal approaches with three-dimensional analysis.

The medico-legal identification is based on a set of discriminatory characteristics between individuals in their biological, social, cultural, religious, legal and economic framework. The purpose of this study was to characterize the biological variation, regarding gender and age, in a Portuguese population. A three-dimensional (3D) analysis of 215 mandibles (7-20 years old) from the database of the Laboratory of Forensic Dentistry, Faculty of Medicine, University of Coimbra (CE-112/2019) was performed. A total of 13 cephalometric points defined 10 linear variables and 7 angular variables, on 3D reconstructions from ConeBeam Computed Tomography (CBCT) images. Intra and inter-observer errors were analyzed by Technical Measurement Error test. A descriptive statistics was performed. To verify the influence of gender and age on the variables and to determine its predictive value, ANOVA and Logistic Regression Analysis were performed. Gender and age influence most of the linear variables, however, the same is not true for angular variables. In the analysis of all variables, the model has a reasonable level of sensitivity (67.8%) according to gender. For the age prediction, with all variables, the model presented a reasonable level of sensitivity, classifying 79.4% of the individuals. The results supported, with a high level of statistical significance, an adequate recognition of individuals highlighting the identification and criminal imputability of Portuguese individuals.