Dental age assessment by the pulp/tooth area proportion in cone beam computed tomography: is medico-legal application for age estimation reliable?

Introduction: Forensic dentistry has, as one of its main goals, the identification of living and/or deceased individuals, based on the individual features of the teeth. One of the identification criteria to be established is the chronological age. Several authors, including Kvaal, have developed age estimation methods based on secondary dentine deposition. Nowadays, three-dimensional imaging tests, such as Cone Beam Computed Tomography (CBCT), are used in age estimation.

Objective: The aims of this research project were to validate Kvaal's method and its variables in age estimation and to create new linear regression formulae to better represent the study sample.

Methods: We selected 158 CBCT, with a total of 402 sound teeth (central incisors, lateral incisors and canines). The necessary measurements and ratios were calculated in both coronal and sagittal sections, with XelisDental . The formulae developed by Kvaal for age estimation calculation were applied. Subsequently, the results were statistically analyzed.

Results and discussion: The intraclass correlation coefficients from the two measurements ranged from 0.918 to 0.997. The calculated age estimation had a mean error of -21.4years (coronal section) and -26.3years (sagittal section). The t test revealed statistically significant differences between chronological age and estimated age. The absolute values of Pearson's correlation coefficient between age and the two Kvaal variables ranged from 0.06 to 0.38 and from 0.06 to 0.55. The coefficients of determination are lower than in the original study (between 0.03 and 0.39). In the linear regression formulae, the coefficients of determination ranged from 0.07 to 0.41.

Conclusion: This investigation concludes a non-reproducibility of Kvaal's method in the Portuguese population when applied in CBCT, with statistically significant differences between the chronological age and the dental age, estimated by the pulp/ tooth proportion method, based on the teeth analyzed in this study.