Age estimation of archeological populations using secondary dentin analysis

Abstract

The innermost dental tissue, termed secondary dentin (SD), has been established as a valuable parameter for aging, as its thickness is highly correlated with age and can be viewed in a non-invasive manner using micro-computerized tomography (μCT). Dental remnants show a high preservation rate in an archeological context and may be used as age indicators, thus possibly supplementing traditional skeletal-based demographics. As the SD age assessment method was based on unworn teeth, in the current study, we adjusted the approach to allow age estimation of highly worn teeth and later to explore prehistoric samples. In order to do so, 90 lower premolars from known age and gender individuals with various degrees of occlusal attrition were included. The teeth originated from the Hamann-Todd Osteologic Collection (Cleveland, OH, USA) and from the Tel Aviv University collection (Israel). Combining SD measurements and occlusal Attrition slightly improved the standard error of age estimate from ±7.7 years based on SD and ±9.5 years based on Attrition to a range of ±6.5 years.The SD-age method was used to evaluate the age of individuals from three Natufian and Neolithic sites using dental remains (Hayonim Cave, Ein Mallaha 14,900–11,750 cal BP, and Kfar Hahoresh ∼12,175–8250 cal BP). Population coverage increased substantially with the addition of forty-eight premolars to previous skeletal age assessments to create new life tables. The addition of dental age assessments, representing unaccounted individuals, shifted the age distributions and increased the expected lifespan between 4.7 and 1.8 years. Using the SD-age analysis, isolated, fragmented teeth can be included in the paleodemographic study, thus broadening the coverage of samples and providing better insight into archaic populations' structure.