Enamel Erosion Inhibition by a Combination of Polymers and Fluoride

Objective: To determine the effect, in vitro, of pre-treatment of enamel with specific polymer-containing solutions on subsequent erosion by a dietary acid. Surface topography changes attributed to erosion were monitored using white light interferometry. Methods: Human enamel specimens were polished and divided into one of six treatment groups: i) deionised water, ii) 300ppm fluoride (sodium fluoride) iii) a novel combination of polymers in 300ppm fluoride iv) a novel combination of polymers in deionised water v) pluronic in 300ppm fluoride vi) a novel combination of polymers and pluronic in 300ppm fluoride. The specimens were incubated for 1 minute in the treatment solutions and subsequently washed with deionised water. Prior to acid exposure, part of the specimen surface was masked by taping. During the erosion phase, specimens were immersed in 1.0% citric acid, pH 3.8 for 5 minutes. Surface topography was investigated using an ADE PhaseShift MicroXAM White Light Interferometer. Results: Surface roughness values (Sa) from enamel treated with deionised water versus enamel treated with the combination of polymers show that they provide some protection to the enamel surface on acid exposure. Enamel treated with the combination of polymers and fluoride had the lowest Sa values, suggesting an additive effect. On removal of the tape mask from the specimens and subsequent measurement of step heights, enamel tissue loss data mirrored the surface roughness findings. Conclusion: This study has shown that treatment of human enamel with an aqueous solution containing three novel polymers provides some protection against surface damage on subsequent citric acid exposure. In combination with fluoride, the protection is additive to that provided by fluoride alone.