Hominid enamel thickness: I. The Krapina Neandertals.

Dental x-rays were taken of isolated and in situ adult molar teeth of the Krapina Neandertal (n = 63) and of recent and contemporary molars (n = 423). The radiographs were digitized at high resolution (1,024 x 1,520 x 8 bits) with a 35 mm solid state scanner. Ratios of enamel cap area to the underlying dentinal-pulpal area were determined and comparisons were made between average ratios for the Neandertal and contemporary molars. Neandertal molars had significantly smaller ratios than did contemporary teeth (P < 0.05). It is suggested that the smaller ratios represent relatively thinner enamel for Neandertals and that the thin enamel may have been caused by a metabolic depression that resulted in reduced enamel quantity (hypoplasia). Alternatively, the observed differences may be related to expanded pulps seen in various stages of taurodontism.