ヒトの大臼歯の頂窩の形態と組織構造および元素組成からみた成因について

抄録

 We examined the shape, histological structure and elemental composition of the crestal pit in unworn human molars. We could distinguished the crestal pit from the pit on the enamel surface which forms the end of the enamel channelling by their histological structure. The shape of the crestal pit was various, such as dish-shaped concave, spiral groove and arch-shaped groove with central dome. The peculiar thick rodless laminal enamel was found at the bottom of the crestal pit in human molar. The contents of Ca and P were significantly higher, while those of C and Mg were significantly lower at this thick laminal enamel of the crestal pit. It was reverse tendency to the similar thick laminal enamel found in the enamel pearl.

 It is thought that the ameloblasts at the processed part of the dento-enamel junction form slow growth laminal enamel, so that the concave crestal pit is formed. It is considered that this thick laminal enamel of the crestal pit is higher calcified, and includes less organic matter than the middle enamel of the cusp part, and differs in nature from the similar thick laminal enamel found in the enamel pearl.