Secondary dentine as an indicato of adult age a 3d CBCT method for age estiamtion based on pulp chamber narrowing of central incisors

Secondary dentin deposition throughout the life of an adult individual results in a progressive narrowing of the pulp volume. Previous studies demonstrated a significant correlation between secondary dentin deposition and age and proposed a new simple non-invasive method of geometric approximation of dental volumes using Cone Beam Computed Tomography (CBCT) with good accuracy especially for age cohorts 30-59 with errors ranging from +/-0.71 to +/-5.86 years respectively. This study aims to evaluate the accuracy of this simple and conservative CBCT method on a larger sample to better predict the subjective viability and improve the reliability of the method for intermediate age cohorts. A total of 500 CBCTs from healthy subjects aged from 18 to 90 years were collected and only the upper left central incisor was chosen to evaluate pulp/tooth volume, the most reliable tooth according to previous review. We examined other teeth, 2.3 , 3.3 that were not reliable due to the difficulty of calculating their volume on CBCT. Not sound teeth were excluded from the study. Two experienced forensic odontologists performed blinded measurements of dental volumes: the root, the pulp and the crown were assimilated to elliptical based solid cones and the volume was calculated by taking nine measurements (3 linear and 6 areas) on DICOM images using RadiAnt software. The ratio between the pulp volume and the hard tissues volume (PHr) was assumed as the significant variable for age estimation in order to reduce errors according to the following formula: PHr = Vpulp/Vht [Vht=Vtot-Vpulp, Vpulp is the volume of the pulp, Vht is the volume of dental hard tissues, and Vtot the total volume of the tooth]. An inferential analysis will be conducted by creating multiples linear regression model with age as dependent variable and PHr as predictor