Laser ablation of enamel and composite using 355-nm laser pulses: influence of fluoride and laser treatment on adhesion

Abstract

Previous studies have demonstrated that Q-switched 355-nm laser pulses can be used to remove composite sealants and restorations from tooth surfaces without significant damage to sound tooth surfaces and have also shown that 355-nm lasers pulses can also be used to selectively etch the interprismatic protein of enamel to increase the effectiveness of topical fluoride for inhibiting decay and increase the bond strength to restorative materials without acid-etching. The first aim of this study was to test the hypothesis that topical fluoride can be applied after laser irradiation before composite resin placement without significantly reducing the bond-strength. The second aim was to test the hypothesis that thermal damage to existing composite due to laser irradiation does not compromise the adhesion of newly applied composite. There was a slight but significant reduction in the magnitude of the shear-bond strength of laser-treated surfaces with and without fluoride application. There was no significant difference in the magnitude of the bond strength between laser irradiated and non-laser irradiated aged composite to newly applied composite. These results suggest that after composite removal with 355-nm laser pulses fluoride can be subsequently applied to inhibit secondary caries before placement of composite restorative materials and that 355-nm laser pulses can be used for the repair of existing restorations.