Ultrastructure of the intact surface zone of white spot and brown spot carious lesions in human enamel.

Abstract

Electron microscopy of the intact surface zone of white spot and brown spot carious lesions showed that in general their ultrastructure was similar. Their outermost crystalline surface consisted of small crystals similar to those in healthy enamel, crystals with central core dissolution, and rounded crystals. Below this, surface demineralization of enamel was observed as the enlargement of micropores, the central core dissolution of crystals, the formation of channels and the enlargement of spaces at prism boundaries. Remineralization of enamel was observed as the partial occlusion of voids, the rounding and enlargement of crystals, and some new needle-shaped crystals. Some other features in..