The effect of topical fluoride application combined with Nd:YAG laser irradiation, on demineralization of enamel - An in vitro study

Background: Fluoride varnishes and laser treatment of enamel have been shown to increase its resistance to acid dissolution.Objective: To evaluate the effect of fluoride varnish and Nd:YAG laser separately, and both combined on the demineralization of enamel.Study design: The resistance of enamel to acid solubility was measured by analysis of calcium ions released into the medium after an acid challenge.Materials and methods: Enamel discs prepared from molars were divided into four groups.Group I: No treatment, Group II: Fluoride varnish applied on enamel surface, Group III: Enamel surface treated with Nd:YAG laser, and Group IV: Fluoride varnish applied enamel surface irradiated with Nd:YAG laser.The specimens were immersed in lactic acid for 24 hours.The calcium dissolved was determined using Flame Photometry.Results: Calcium dissolution was significantly reduced by fluoride varnish application on enamel (Group II).Nd:YAG laser irradiation (Group III) gave a significantly lesser calcium dissolution than Group II.Dissolution was least when Nd:YAG laser irradiation was done on fluoride varnish applied enamel (Group IV).Conclusions: Application of fluoride varnish on enamel significantly increased its resistance to acid solubility.Nd:YAG laser irradiation of enamel increased its resistance to acid solubility better than topical fluoride varnish application alone.Least demineralization of enamel occurred when fluoride varnish applied enamel was subjected to Nd:YAG laser irradiation.