Laser radiation propagation in the hard and soft dental tissues

Abstract

The objective of this study was to compare the penetration effect of the near and mid-infrared laser radiation. For this reason the Er:YAG, Nd:YAG, and alexandrite laser systems were used in the experiments. The spread of the laser radiation energy in the hard dental tissue surrounding the root canal was evaluated and the possible bactericidal effect of these various laser wavelengths was analyzed. During the measurements, three experimental arrangements were used. The energy transport through the tooth tissue was observed for the frontal and side experimental layout. It was demonstrated that due to the absorption in the hydroxyapatite and water content in the dentin, the Er:YAG laser radiation is fully, and the Nd:YAG is partly absorbed in the root canal's wall. On the other hand, it was proved that the alexandrite laser radiation spreads through the canal system space and leaks into the surrounding tooth tissues. All laser radiation can be efficiently used for killing dental bacteria but the spreading of their radiation in the tooth tissues is different.