APPLICATION OF CF-252 PLASMA DESORPTION MASS-SPECTROMETRY IN DENTAL RESEARCH

Topically applied fluorides as introduced in dental hygiene products elevate the concentration levels of fluoride in oral fluids and thus also affect chemical reactions of enamel de- and remineralisation. The chemical reactions on the surface of tooth enamel still are a subject of controversy. Here Cf-252-plasma desorption mass spectrometry and argon ion etching are used to analyse the molecular structure of the upper layers of enamel. The mass spectrum of untreated enamel is characterised by a series of cluster ions containing phosphate. It is evident that under certain conditions the molecular structure of the surface enamel is completely transformed by treatment with fluorides. The result of the degradation and precipitation processes is reflected by a total replacement of the phosphate by fluoride in the measured cluster ion distribution. Stepwise etching of the upper layers by Ar+ ions reveals the transition from a nearly pure CaF2 Structure to the unchanged composition of the enamel mineral.