Age estimation using third molars in forced migrant populations: Determining age and probability

Accurate age estimation is a critical component of forensic assessment in undocumented forced migrants, as it directly influences legal protection, social support, and immigration procedures.

To develop and validate a statistical model for estimating chronological age and its probability distribution based on third molar maturity index values in forced migrants.

In this observational study, we employed a Bayesian Calibration approach utilizing a Normal density and an expected value modeled by a Segmented function. The model underwent calibration using a training sample consisting of 481 orthopantomographs of healthy males, gathered during routine visits spanning from 2012 to 2017. A testing sample comprising 45 forced migrant males recruited from four Italian hosting centers in 2018 was utilized to validate the model.

The two samples exhibited similar distributions in terms of age and dental maturity index. The model's breakpoint age was estimated at 18.6 years, suggesting a sharp decline in dental maturity rate beyond this threshold. For instance, the probability of a forced migrant being 18 years or older with a dental maturity index of 0.15 was 0.75. The mean error in age estimation was 1.57 years, with a variability of 2 years, and demonstrated a statistically significant increasing trend of 0.3 years.

The model offers, in addition to estimated age, the likelihood that an individual is of a specific age or older, taking into account their dental maturity. This provides valuable supplementary information to authorities during the age assessment procedure. A web application has been launched to facilitate the retrieval of age estimates and associated probabilities when inputting the dental maturity index value.