Journal of Dental Research, Vol 66, 1647-1653, Copyright © 1987 by International & American Associations for Dental Research Online Journals
Intracrystalline structure of enamel crystals affected by caries
H. Tohda, S. Takuma and N. Tanaka
Department of Oral Pathology, Tokyo Dental College, Chiba City, Japan.
Enamel crystals in the demineralized zones in early caries lesions of human
teeth were observed by high-resolution electron microscopy. The enamel
crystals frequently exhibited perforations in their centers and defects of
various sizes on their lateral surfaces. There were a number of small
electron-lucent spots, suggesting that the dissolution of crystals had
taken place there. These spots were in especially large numbers near the
central dark line. The central perforations, the lateral defects, and the
small spots had a common habit which formed regularly along the crystalline
a- and b-axes. In many cases, when the central dark line was seen, the
perforations were located a few unit cells away from the line. The
perforations seem to result from a fusion of small spots, which enlarge by
involving other small spots. The lateral defect seemed to enlarge by
removal of unit cells and progression along the a- and b-axes. In the
regions where the small spots were present, however, the enlargement of the
defects also progressed involving the spots. The central dark line seems to
be rather resistant to dissolution. One of the main factors for the central
perforation of the crystals is thought to be the presence there of
especially large numbers of defective sites.
