Estimation of lip position from alveolar ridge measurements using sex- and age-specific regression models in a Korean population

Craniofacial reconstruction is a pivotal process in identifying unknown individuals by estimating facial feature positions and soft-tissue thickness from the skull. However, the oral region presents a significant challenge because the lips, composed primarily of muscle and skin, lack direct attachment to the underlying skeletal structure. This study aimed to bridge this gap by establishing a relationship between the alveolar ridge and lip morphology within a Korean population. Under 10-fold cross-validation, the proposed sex- and age-specific regression equations achieved an overall mean absolute error of 1.445 mm, with 73.8% of predictions falling within the ± 2.0 mm forensic threshold. The results identified several alveolar ridge dimensions as statistically significant predictors of lip morphology. These findings provide reference data tailored for the Korean population. By replacing subjective estimations with objective, data-driven equations, this study offers a standardised reference for forensic facial approximation in Korean adults.