Age-at-death estimations using cementochronology in thermally altered teeth

Abstract

Macroscopic age-at-death estimations provide age ranges that give broad and often insufficient insight to an individual’s chronological age. Accurate age estimations can become more complex for a forensic anthropologist if the unknown individual has been subjected to extreme heat from an assortment of scenarios that include but are not limited to structure fires, airplane crashes, automobile accidents, and attempts to conceal evidence of homicide. Due to their high mineral content and sequestered placement in the jaw, teeth have the ability to be one of the best-preserved human tissue remains in extreme heat situations (Beach, Passalacqua, & Chapman, 2015). Cementochronology utilizes the cementum, the mineralized covering of a tooth root, as an aid in estimating an individual’s age (Colard, et al., 2015). The utilization of cementochronology is one of the most accurate ways to estimate age-at-death due to the countable cementum annulations found in the cross-sections directly correlating to the individuals age (Wittwer-Backofen, 2004). This study aims to provide an in-depth analysis of thermal alteration to human teeth by various accelerants when utilizing the cementochronology method to build a biological profile. The sample in this study consists of 36 teeth from both male and female donors from all odontological positions ranging in age from 9-87 years. Three accelerants with varied volumes were used to determine if the readability of cementum annulations can still remain accurate after alteration. Results indicated that the type of tooth had significant impact on the ability to count annulations. Annulations were able to be read and estimated after alteration with all three accelerants used in this study. However, acetone yielded the lowest results with the most severe alterations. A novel formula was developed to help approximate the amount of cementum annulations found within each sample. This formula was found to yield estimated tooth cementum annulations that were highly correlated with the actual ages of the individuals from whom the samples were from. After thermal alteration of teeth with accelerants it was found that cementochronology is an accurate and helpful tool for estimating age-at-death in unknown individuals.