AGE ESTIMATION BASED ON A 3D CBCT STUDY OF THE PULP CAVITY AND HARD TISSUES OF THE TEETH FOR FORENSIC PURPOSES

BACKGROUND Age estimation is a mainstay of the reconstructive identification pathway of the living individual as well as of the dead, and, among the others, the odontological methods are considered to be quite reliable. In the adults, the dental age can be estimated by the analysis of the progressive physiological and degenerative phenomena which affect the tooth and, among them, the secondary dentinal apposition. Along with the histo-pathological methods of dental age estimation, the recent introduction of the devices for the three-dimensional processing of the radiographic images of the teeth – such as the modern CBCT – allows the adoption of a non-invasive/destructive, reliable and rather accurate method for dental age estimation. AIM The aim of the present research is to develop a non-invasive, conservative, reliable, accurate and simple method of dental age estimation in the living by mean of the analysis of the volume decrease phenomena which affect the pulp cavity of the teeth. The experimented method provides a specific software which allows the measurement of the volume of dental hard and soft tissues on the base of the three-dimensional radiographic images from the CBCT MATERIALS AND METHODS Two operators have randomly selected and analyzed 300 CBCT radiographs of caucasian subjects made for ordinary clinical purposes (Scanora 3D dental cone beam unit - Soredex, Tuusula, Finland). The sample of the CBCTs consists of 116 male individuals and 179 females in the age cohorts between 10 and 79 years. The image of the upper left central incisor has been extrapolated from the radiographs in DICOM file format (OnDemand 3D software - CyberMed Inc, Seoul, South Korea). To measure the volume of the dental tissues involved, the images have been then elaborated with an innovative method of geometric approximation of the dental anatomy: the ratio “pulp cavity volume/dental hard tissues volume” has been obtained and then correlated with the age of the subject. An inter-rater agreement has been performed. The results have been statistically analyzed and a special but easily usable formula has been elaborated. RESULTS The research needs to be implemented with the results from a larger number of exams before drawing final conclusions. The preliminary results are encouraging since the CBCT and the adopted method allow a precise and accurate measurement of the volume changes of dental tissues caused by ageing. The research shows a high correlation between dentinal apposition and the calculated ratio, and the age of the individuals with respect of gender and age cohort. Moreover the study of the volume instead of the linear or area measurement of the dental structures seems to be a promising approach, being the volume less influenced by x-rays distortion. The easy calculation of the rate with the proposed method has taken no more than 10 minutes each. Hence the method is quick and simple, and offers the best chance to reveal and to measure the correlation of such volume changes with the age of the subject thus obtaining useful evidence to assess age of a living adult in forensic practice. CONCLUSION The presented method is a promising tool in the procedure for age estimation, permitted by the high technological level achieved by the currently available machines for the CBCT. Due to the correlation with age, the low dose exposure to x-rays, the conservative and easy approach, the save of time and the economically irrelevant difference in costs between the CBCT and the OPG exam, the adopted procedure can be considered technically reliable and affordable for forensic purposes.