Tooth cementum annulation for age estimation: results from a large known-age validation study.

Recent research indicates that tooth-cementum annulations (TCA) may be used more reliably than other morphological or histological traits of the adult skeleton to estimate age. Until now, however, confidence intervals for age estimated by this method have not been available for paleodemographic and forensic applications. The present study addresses this problem. Based on a large known-age sample, age estimates by TCA were conducted in a blind study involving 363 teeth. Tooth-root cross sections were made using a refined preparation technique. Improved digital graphic procedures and enhancement strategies were used to produce digital images with a specially adapted software package. This resulted in high concordance between the TCA age estimates and chronological age. Assessment of the method's accuracy, as expressed by 95% confidence intervals, showed that error bounds for age estimates do not exceed 2.5 years. Sex differences, intraindividual correlations, and the effects of periodontal disease were studied. None of these indicators had a quantitative effect on the number of TCA bands when the proposed methodological standard was followed. We conclude that the TCA technique is a reliable method for estimating a subject's age from cementum annulations.