Micromorphometric analysis of cervical enamel structure of human upper third molars.

Fifty-two teeth were sectioned and embedded such that the structural characteristics of the palatal enamel could be examined by scanning electron microscopy. Measurements were made of the height of aprismatic cervical enamel, of cervical enamel with atypically shaped prisms, and of cervical enamel without Hunter-Schreger bands. Enamel thickness 80, 1000 and 2500 microns occlusally from the cervical enamel border, the maximum thickness of cervical enamel with atypical prism shape and that of aprismatic cervical enamel, and the thickness of occlusal enamel were also measured. The height of cervical enamel with atypical prism shape ranged between 103 and 756 microns, and was inversely related to the thickness of typically structured enamel, suggesting that atypical enamel formation follows some order. Atypical enamel in the cervical area may affect caries susceptibility as well as the efficacy of acid-etching in this region.