Potential of yttrium‐aluminum‐garnet laser in caries prevention

Abstract. Intact tooth enamel of extracted human teeth was exposed to a pulsed Nd‐YAG laser at an energy density of 10 to 20 joules/cm 2 . In vitro demineralization by lactic acid was accomplished by dextran‐producing strains of Streptococcus mutatis PK‐1 growing on the enamel surface. Scanning electron microscopic observations on the laser irradiated enamel supported micro‐radiographic findings and indicated that the laser irradiated enamel surface was more resistant to decalcification than the non‐irradiated control enamel. Surface changes suggestive of fusion occurred at the low energy density of 10 to 20 joules/cm 2 . Laser beam irradiation imparted a degree of alteration to enamel surface that subsequently reduced subsurface demineralization. A significant difference in solubility was found between laser irradiated and non‐irradiated enamel.