Measuring Root Dentine Translucency in Human Teeth of Varying Antiquity

Many workers have calibrated human root dentine transparency (RDT) as a linear regression on age. It is now regarded as a well-established means of estimating age at death in modern human material. Similar applications in archaeological material have not yet been developed. The aim of this study was to establish a standard protocol for measuring RDT which was derived from previous methods and which could be applied to teeth of unknown and varying antiquity. An initial study on two archaeological populations determined the choice of tooth to study and a second study, using expendable teeth (of unknown age and origin), evaluated various techniques of specimen preparation and examination. Findings from the pilot study indicated that the lower canine was the tooth of choice. From the second study it was observed that archaeological teeth could only be sectioned if they had first been infiltrated and embedded in methyl methacrylate. The optimal section thickness was found to be 150 μm and no benefit was gained by staining. Inter-observer reliability tests showed significant differences in repeated measures of RDT in intact teeth, which were not borne out when sectioned teeth were used. Intra-observer reliability was maintained for measurements in both intact and sectioned teeth. These findings have been used to establish a standard protocol for application to human teeth of any depositional phase to estimate the dental age at death of that individual.