Surface changes in dental enamel and dentin resulting from laser irradiation

Abstract

We studied surface changes in dental enamel and dentin by resulting from laser irradiation utilizing Nd: YAG and CO₂. Polished surfaces of enamel and dentin were prepared as samples. The structure of the laser irradiated enamel and dentin surfaces were observed by atomic force microscopy (AFM) and scanning electron microscopy (SEM), and analyzed by electron spectroscopy for chemical analysis (ESCA). AFM observations demonstrated contiguity of the enamel crystals, which gradually melted with increasing laser power. The rounded dentin crystals became square with increases in the laser power. Nd: YAG laser irradiation produced greater changes than did CO₂. It seems that laser irradiation should enhance acid resistance of the surface as a result of decreases in the surface area of the enamel and dentin crystals. SEM observations showed that the irradiated enamel surfaces were smoother than those of the controls. ESCA analysis of the laser irradiated enamel indicated that low power laser irradiation produced new calcium phosphate products on the enamel surface, and that low energy CO₂ laser irradiation reduced organisms on the dentin surface.Shika Igaku (J Osaka Odontol Soc) 1997 Mar； 60(1)：45-57．