Journal of Dental Research, Vol 61, 423-428, Copyright © 1982 by International & American Associations for Dental Research Online Journals
Electron spectroscopic studies of interactions between superficially-applied fluorides and surface enamel
H. Uchtmann and H. Duschner
Despite comparable acidities and fluoride concentrations, distinctly
different characteristics of fluoride deposition and enamel degradation
were observed. In the sequence of the amine hydrofluorides, this may
possibly be due to the increasing cation polarity. Thus, by the concomitant
rise in the dissociation constants of the compounds, the increasing
effectiveness of fluoride accumulation is due to the presence of more free
fluoride in solution. On the other hand, sodium fluoride shows behavior
comparable to that of the unsaturated amine hydrofluoride. Presumably,
specific interactions between the cations and surface apatite may favor
fluoride deposition. Under present conditions of treatment, however,
neither sodium nor quaternary ammonium cations are deposited in significant
amounts on tooth surfaces. Thus, the behavior of fluoridizing agents cannot
be understood only by their properties in bulk solution. Obviously,
specific reaction mechanisms between surface-adjacent solutions and enamel
apatite must be considered. Similar reactions have been studied extensively
in connection with corrosion problems. The investigations clearly
demonstrated that, for the interpretation of mechanisms, all relevant
parameters must be considered: the ionic composition of solutions, the
temperature, the time of treatment, etc. Thus, a series of additional
experiments will be necessary for more insight into the reaction mechanisms
of fluoride on superficial dental enamel. The consequence of the present
studies is that the cariostatic effect of superficially applied
fluoridizing agents cannot be discussed in terms of fluoride accumulation
only.
