Ο σεξουαλικός διμορφισμός της κάτω γνάθου σε Ελληνικά PMCTs ως εργαλείο εκτίμησης φύλου

Abstract

Sex estimation is a crucial aspect of forensic anthropology, as it contributes to the biological profile necessary for identifying unknown individuals. While the pelvis remains the most reliable skeletal element for sex estimation due to its pronounced sexual dimorphism, alternative methods are needed when the pelvis is unavailable. The mandible, being one of the most durable bones in the human skeleton, offers a potential alternative for sex estimation. This study evaluates the effectiveness of mandibular measurements in sex estimation using Post- Mortem Computed Tomography (PMCT) scans of a Greek population. A total of 106 individuals (31 females and 75 males) were selected for this study, with cases sourced from the Forensic Medicine Unit of the University of Crete Medical School, at the University General Hospital of Heraklion (PAGNI). The selection criteria ensured that all individuals were of Greek ethnicity and within the age range of 20 to 90 years. Mandibular measurements, including chin height (CH), bicondylar breadth (BCB), bigonial breadth (BGB), bimental breadth (BMB), and minimum ramus breadth (MRB), were taken from segmented PMCT images using 3D Slicer software. Statistical analyses, including independent t-tests, linear discriminant analysis (LDA), and recursive feature elimination (RFE), were performed in R and R Studio to determine the most predictive variables for sex estimation. Results indicated significant sexual dimorphism in mandibular measurements, with males generally exhibiting larger values than females. Among the variables tested, bigonial breadth (BGB) was found to be the most predictive feature, achieving an accuracy of 83.33% in sex classification. Bimental breadth (BMB) also demonstrated strong predictive power, with an accuracy of 81.48%. Chin height (CH) and bicondylar breadth (BCB) were moderately effective, achieving 64.81% and 70.37% accuracy, respectively. When multiple mandibular measurements were used in an LDA model, an overall classification accuracy of 81.48% was achieved for test data. The formulae developed by Kranioti, Gómez García-Donas, and Langstaff (2014) for Greek mandibles were applied to the current dataset for validation. The first formula (F1) achieved an accuracy of 78.30%, while the second formula (F2) resulted in an accuracy of 74.53%. 6 However, a notable misclassification of female mandibles as male was observed in both cases, suggesting potential secular changes or population-specific variations influencing mandibular morphology. Despite promising results, the study faced limitations, including an imbalanced sex ratio in the dataset, which may have impacted classification accuracy. Additionally, age-related bone resorption, particularly in older individuals with poor dental health, posed challenges for measurement consistency. Future research should focus on increasing sample size, addressing secular changes, and incorporating machine learning techniques to enhance predictive accuracy. Furthermore, cross-population validation is necessary to determine the broader applicability of the findings. This study demonstrates that mandibular measurements derived from PMCT scans offer a viable method for sex estimation in forensic and bioarchaeological contexts. While not as reliable as pelvic-based methods, the mandible provides a useful alternative when other skeletal elements are unavailable. The use of PMCT imaging enhances methodological precision, reducing inter-observer error and allowing for non-invasive forensic assessments. Continued refinement of mandibular-based sex estimation methods could contribute significantly to forensic anthropology and medico-legal investigation