Estimation of age based on tooth cementum annulations using three different microscopic methods

Abstract

Background: The hard tissues of human dentition are able to resist decay and degradation long after other tissues are lost. This resistance to decay has made teeth useful for calculation of age at death of an individual. Recent research indicates that tooth cementum annulations (TCA) may be used more reliably than other morphological or histological traits of the adult skeleton for estimation of age. Objectives: The purpose of this study was to examine the correlation between age and the number of incremental lines in human dental cementum and to ascertain which, among three different forms of microscopy (light, polarized, phase-contrast) was the most reliable method of studying cementum. Materials and Methods: The study sample consisted of 40 teeth that had been extracted from patients ranging in age from 20−70 years. Longitudinal ground sections of each tooth were prepared and examined under light microscopy, polarized microscopy, and phase-contrast microscopy. The images were magnified on a computer and the cemental lines were counted with the help of Image Analysis Pro 6.0 software. Only the dark lines were counted. Results: There was a strong positive correlation between the estimated age and calculated age when phase-contrast microscopy was used; the correlation was less for light and polarized microscopy. Our results suggest that there is no significant influence of sex, age, periodontal disease, or tooth type on age estimation by the TCA method. This suggests that the accuracy and repeatability of the method is not dependent on tooth type or location and that this method can be applied to the general population regardless of systemic or periodontal health. Conclusion: With this study we conclude that among the methods of counting incremental lines by various types of microscopy phase-contrast microscopy improves the accuracy of age estimation and may serve as a valuable aid in forensic identification.