Characteristic changes of lased dentin

摘要

Abstract: The present study investigated the effect of CO$-2$/ laser irradiation on dentin underneath the carious dentin that is to be removed.The investigation consisted of two experiments. In the first experiment, morphological and elemental changes of extracted human dentin irradiated by the CO$-2$/ laser were observed by microscope, SEM and XMA. In the second experiment, changes in hardness of bovine dentin irradiated by the CO$-2$/ laser were examined. Panalas C10, a CO$-2$/ laser with a flexible optical fiber, was used with different total energies for both experiments. The present study showed that CO$-2$/ laser irradiation made a significantly harder arched layer underneath the superficial carbonized layer in dentin. It seemed that this harder layer occurred where the dentin tubules were plugged with particular structural elements, and where there was a high concentration of calcium and phosphorus. It is suggested that use of the CO$-2$/ laser irradiation to remove carious dentin may have an additional effect that enhances the mechanical and chemical properties of the dentin layer underneath the carious dentin.!8