Tin and fluoride as anti-erosive agents in enamel and dentine in vitro.

OBJECTIVE: To investigate the efficacy of an experimental tin- and fluoride-containing mouth rinse on progression of erosion in enamel and dentine in vitro.

MATERIAL AND METHODS: Human enamel and dentine specimens were subjected to a cyclic demineralization and remineralization procedure for 10 days, with six 5-min demineralization periods per day. Erosive demineralization was performed with 0.05 M citric acid (pH 2.3). Except in the negative control group, the specimens were treated for 2 min with mouth rinses after the first and sixth demineralizations. An experimental tin-containing fluoride mouth rinse [125 mg/kg F(-) (amine fluoride), 375 mg/kg F(-) (NaF), 800 mg/kg Sn(2+) (SnCl(2))] and an experimental sodium fluoride mouth rinse (500 mg/kg F(-)) were used (both pH 4.5). A commercially available, tin-containing mouth rinse served as a positive control (pH 4.2, 409 mg/kg Sn(2+), 250 mg/kg F(-)). Tissue loss was determined profilometrically.

RESULTS: The highest tissue loss was found in the negative control group, in both enamel and dentine. In enamel, the NaF solution showed almost no effect. Both tin-containing solutions significantly reduced tissue loss (positive control: 65%; 800 mg/kg Sn(2+): 78%; both p ≤ 0.001 compared to negative control). In dentine all mouth rinses significantly reduced tissue loss (positive control: 43%; 800 mg/kg Sn(2+): 53%; NaF: 40%; all p ≤ 0.001 compared to negative control).

CONCLUSIONS: In enamel, the efficacy of mouth rinses depended on the compound used; tin-containing preparations were notably effective. In dentine, however, reduction of substance loss was nearly the same in all treatment groups.