脱灰エナメル質の再石灰化に及ぼすレーザー照射の影響

Abstract

The purpose of this study was to examine the influence of laser irradiation on remineralization of demineralized enamel. Twenty human premolar enamel slabs (3×5mm) were prepared for this study. The enamel slabs were ground down to about 400μm and immersed in 0.1M lactic acid buffer (3.0mM Ca, 1.8mM P, 1.0% carboxymethylcellulose, pH 4.5, 37°C) for 12 hours. Demineralized enamel slabs were irradiated with a Q-switch Nd-YAG laser at 50 J/cm2of total energy density. After laser irradiation, slabs were immersed in remineralizing solution (3.0mM Ca, 1.8mM P 1.0% carboxymethylcellose, 150mM NaCl, 3.0ppm F, pH 7.0, 37°C) for 10 days. The degree of remineralization was evaluated by microradiograph using calculated mineral content. Sectioned enamel slabs were also immersed in 0.5M HClO4solution for 1 minute to examine acid resistance of the remineralized enamel.There were signs of remineralization in both the lased and unlased areas, and no clearly difference was recognized between these areas. It appears that remineralization of enamel was not inhibited by laser irradiation. The acid resistance of the remineralized enamel was higher in the lased area than in the unlased area. However, the degree of remineralization corresponding to the mineral level was not significantly different between two areas. It is probable that the permeability of enamel was not decreased by laser irradiation.