Atlanto-axial morphometric measurements for age and sex estimation: a retrospective cone beam computed tomography...

Accurate determination of age and sex is fundamental in forensic anthropology, archaeology, and clinical diagnostics. Conventional methods are often limited by subjectivity and low precision. Cone Beam Computed Tomography (CBCT), with its high-resolution three-dimensional imaging, offers a reliable alternative for evaluating craniofacial structures. This study aimed to assess the utility of atlantoaxial morphometric parameters, particularly the atlantodental interval, in age and sex determination using CBCT. A retrospective observational study was conducted on 200 full-field CBCT scans (100 males, 100 females) of individuals aged 20-80 years. Scans meeting inclusion criteria were analyzed using standardized protocols. Eight parameters related to atlas (C1) and axis (C2) morphology and atlantodental intervals (AADI, PADI, LADI) were measured. Statistical analysis included ANOVA, independent t-tests, effect size estimation, and discriminant function analysis. Most parameters showed no significant variation across age groups, except posterior atlantodental interval (PADI), which demonstrated statistical significance. Sex-based comparisons revealed significantly greater atlas and axis dimensions in males (p < 0.01), indicating marked sexual dimorphism. Effect size analysis showed very large effects for atlas measurements and moderate to large effects for axis parameters. Discriminant analysis identified axis vertical length as the most reliable predictor of sex (accuracy: 82.5%), followed by axis anteroposterior length (72%). Atlantodental interval measurements showed limited discriminatory value. Atlantoaxial parameters exhibit selective age- and sex-related variations, with axis measurements demonstrating the highest utility for sex estimation. However, overall diagnostic accuracy remains moderate, indicating that these parameters should be used adjunctively. Further large-scale studies are required to validate their application in forensic and clinical settings.