Abstract
We investigated the possibility of treating the smear layer by laser irradiation. The surface of the smear layer was irradiated with a laser, and the changes were observed under a scanning electron microscope. A Nd-YAG laser (Osada YAG Laser) and a CO2 gas laser (Mochida Medilaser-MIC 30) were used in defocus. The results showed that both lasers induced changes in the smear layer. Depending on the irradiation level, the smear layer on the intertubular dentin was satisfactorily treated, with the tubular orifices closed.
Next, we determined the penetration of 1% methylene blue from the dentin surface when irradiated by both lasers under various conditions. It was found that while the dye applied to a non-irradiated dentin surface penetrated deeply over the entire area, an irradiated surface blocked dye penetration. This finding was also observed at low energy densities of 25-50J/cm2, which is very interesting from the standpoint of preserving dental pulp.
