Investigation of the Effect of Various Fluoride Compounds and Preparations Thereof on Erosive Tissue Loss in Enamel in vitro

Abstract

Metal fluoride preparations are promising in view of protection against dental erosion. The aim of this study was to screen the effect fluoride preparations containing various polyvalent metal cations had on erosion progression under increasingly severe erosive conditions in human enamel in vitro. Specimens were subjected to a cyclic de- and remineralisation procedure. Demineralisation (experiment E1 and E2a: 6 × 2 min/day, experiment E2b: 6 × 5 min/day) was performed with 0.05 M citric acid (pH 2.3). Fluoridation directly followed demineralisation and was reduced stepwise (E1: 6 × 2 min/day, E2a and E2b: 2 × 2 min/day). The test solutions were: ZnF₂(E1), AmF/NaF/CuSO₄ (E1), TiF₄/AmF/Zn lactate (E1), TiF₄ (E1, E2a), TiF₄/AmF (E2a), TiF₄/AmF/NaF (E2a), TiF₄/AmF/ZnF₂ (E1, E2a, E2b), AmF/NaF/SnCl₂ (2,800 mg/l Sn²⁺; E1, E2a, E2b), AmF/NaF/SnCl₂-1 (700 mg/l Sn²⁺; E2a, E2b), all 1,500 ppm F^–, pH 4.5, and AmF/SnF₂ (positive control, pH 4.2, 250 ppm F^–; E1, E2a, E2b). In the negative control group, specimens were not fluoridated. Tissue loss was determined by profilometry after the last experimental day. Under mild conditions (E1), tin- and titanium-containing solutions were of marked efficacy and could nearly completely inhibit erosive tissue loss (reduction between 94.2 and 97.5%). With increasingly severe conditions (E2a, E2b), titanium lost its efficacy. Only the highly concentrated tin preparation (2,800 mg/l Sn²⁺) was able to reduce erosive tissue loss by 93.1%, even under severe conditions (E2b), with less frequent application of the experimental preparations. It should be considered for approaches for a symptomatic therapy of dental erosion.