Morphological study of calcospherites in rat and rabbit incisor dentin.

Calcospherites from incisors of rats and rabbits were studied, by means of secondary and backscattered electron images, using scanning electron microscopy. Part of each incisor specimen was made anorganic to allow observation of the surface of the mineralization front by scanning electron microscopy; the other part was ground on one side for observation by scanning electron microscopy with a backscattered electron image detector. In both species the labial mineralization front was wavy and the image showed fused calcospherites, whereas the lingual mineralization front appeared to consist of a combination of linear and globular forms. In rat labial dentin the calcospherites were large and globular form, but they did not develop in the lingual dentin and were small and oval. The shape and size of rabbit incisor calcospherites varied from the pulp horn to the root apex. There were great differences between rats and rabbits with respect to the size and shape of the calcospherites at the mineralization front. This may be due to species differences and possibly the differing rates of dentinogenesis in rats and rabbits.