In vitro treatment of human root surfaces with fluorides

Two-minute topical applications with four different fluoride compounds, acidulated phosphate fluoride, sodium fluoride, sodium monofluorophosphate and stannous fluoride, were evaluated for ability to reduce the acide solubility of human root surfaces in vitro. Each fluoride was in aqueous solution with the fluoride level adjusted to 1.23 percent and the pH native. Rectangular windows were prepared on root surfaces and control versus test differences were invariably studied within teeth and not between teeth. Sodium fluoride and sodium monofluorophosphate solutions reduced root surface solubility by approximately 30 percent while acidulated phosphate fluoride and stannous fluoride were more than 2.5 times more effective, the solubility reduction exceeding 80 percent. Root surfaces thus are similar to enamel in their reactions to topically applied fluorides. Based upon these results the clinician should choose between acidulated phosphate fluoride and stannous fluoride when making the choice of a single treatment compound for office application.