Journal of Dental Research, Vol 64, 12-18, Copyright © 1985 by International & American Associations for Dental Research Online Journals
Influence of repeated APF applications on long-term remineralization of initial lesions in bovine enamel
H. E. Bodde, D. G. Nelson, P. G. Koops and J. Arends
Initial lesions in bovine enamel were remineralized in vitro for periods
lasting from one hour to two weeks; in some cases, remineralization was
interrupted daily for a ten-minute APF application. After two weeks,
surface coatings appeared on APF-treated specimens; SEM and TEM
observations, including selected area and micro-electron diffraction,
indicated both a layered structure within these coatings, and the
predominance of calcium fluoride single crystals, ranging from 0.1 to 1.0
micrometer in size. Using double (45 Ca and 32 P) labeled remineralizing
solutions, we obtained depth profiles of deposited labeled calcium and
phosphate; these indicated that repeated APF applications prevented inward
penetration of calcium and phosphate and limited the deposition of these
ions to an outer surface region corresponding to the surface coating. These
phenomena are explained in terms of the composition and apparent reactivity
of the coating.
