The radiographic visibility of the root pulp of the third lower molar as an age marker

The aim of this work was to determine the usefulness of the visibility of the dental pulp in lower third molars in forensic age estimation.

Dental pulp visibility on lower third molars was assessed using a sample of 487 orthopantomograms. Intra and inter-observer agreement was determined using the Cohen's kappa test. A descriptive analysis of the stages according to age was done. The relationship between age and stage attainment was assessed using Chi square test and the strength and direction of the linear relationship between pulp visualization stage and chronological age was evaluated using Spearman rank order correlation (rho). Equations for predicting an age above 21 years were developed using logistic regression. The level of significance was defined at p < 0.05.

The relationship between age and stage attainment had statistical significance for both sexes (p < 0.001). There was a medium positive correlation between the two variables for both genders (Spearman ρ = 0.420, p < 0.001 and Spearman ρ = 0.454, p < 0.001, for males and females respectively). The model built for age estimation successfully predicted age over 21 in 96.2% of the females and in 96.9% of the males. However, only 19.6 and 27.0% of predictions were accurate for the group that was younger than 21, for females and males, respectively.

The accuracy of predictions for the group younger than 21 years of age was low, meaning that this methodology may not be suitable for age estimation. Still, stage 3 alone proved to be a suitable age marker for determining an age over 21 years.