Assessment of periodontal ligament visibility in third molars for threshold-based forensic age estimation: a cross-sectional study in a Turkish population

Overview

This cross-sectional study evaluated periodontal ligament (PDL) visibility staging in third molars as a forensic age estimation marker for individuals near the 21-year legal threshold. Using the Olze et al. staging system on digital orthopantomograms from a Turkish population aged 15–25 years (n=1,049), the research examined associations between PDL visibility patterns, chronological age, sex, and tooth position to assess diagnostic utility for threshold-based classification rather than precise age determination.

Methods and approach

Retrospective analysis of 1,049 digital orthopantomograms from individuals aged 15–25 years was performed. PDL visibility in maxillary and mandibular third molars was classified using the Olze et al. staging system. Statistical associations were established between PDL stages and chronological age, sex, and tooth position. Diagnostic performance for identifying individuals aged 21 years or older was evaluated through receiver operating characteristic (ROC) curve analysis. Intra- and inter-observer agreement was assessed to confirm methodological reliability.

Key Findings

Advanced PDL visibility stages demonstrated significant associations with increasing age. Mandibular third molars exhibited more informative staging patterns than maxillary counterparts. ROC analysis yielded an area under the curve (AUC) of 0.79 for the 21-year threshold discrimination, indicating good discriminative accuracy with balanced sensitivity and specificity. Substantial intra- and inter-observer agreement confirmed the reproducibility and methodological robustness of PDL visibility assessment.

Implications

PDL visibility staging in third molars represents a reliable and reproducible complementary tool within forensic age estimation protocols targeting the 21-year legal threshold in Turkish populations. The method supports probabilistic decision-making in threshold-based age assessment rather than providing precise age predictions, thereby contributing to multimodal forensic age estimation frameworks. Integration of PDL staging with additional skeletal, dental, and morphological markers may enhance diagnostic accuracy in legally relevant age assessment contexts.