Studies on dental erosion:: An in vivo in vitro model of endogenous dental erosion -: its application to testing protection by fluoride gel application

Background: The objective in this study was to develop an in vivo-in vitro model of endogenous erosion, with a view to exploring the potential for some degree of its control by the use of topical fluoride gel application to teeth. Methods: Six volunteers each wore a small clasp retained palatal acrylic appliance to which six sterilized enamel tiles were bonded. Three tiles on each appliance were coated extra-orally with either 1.23 per cent acidulated phosphate fluoride (APF) or 2.2 per cent sodium fluoride (NaF) neutral gel for four minutes prior to multiple periods of exposure to the simulated gastric acid, cumulating in 16, 36, 80 and 150 minutes of exposure. Impressions of the enamel tiles prior to and following acid exposure permitted dies to be prepared. These were sectioned through the exposed areas and examined under a stereomicroscope to assess maximum depths of erosion. Results: The depth of erosive demineralization of enamel was found to be greatly reduced with increased frequency of APF gel application. The reduction in enamel loss was less following topical application of NaF gel. Conclusions: It was concluded that fluoride gels significantly reduced enamel erosion using this in vivo-in vitro model and therefore, if prescribed appropriately, should help reduce tooth tissue loss from endogenous erosion.