Effects of irradiated conditions of Er:yttritium–aluminum–garnet laser on tooth vibration

Abstract

Clinical studies that the Er:yttritium–aluminum–garnet (YAG) laser cause less pain in cutting. Unlike high-speed drilling Er:YAG laser irradiation does not cause pain by vibration, pressure, heat, or noise. We suspected that the greatest difference in characteristics between the Er:YAG laser and the high-speed drill is the amount of tooth vibration during cavity preparation. It will be simultaneously pain or discomfort during tooth cutting. Previously, the authors revealed that increased vibration speed was observed with an increase in Er:YAG laser irradiated energy, and different characteristic of Er:YAG laser and high-speed drill. However, the vibration speed was also influenced by other irradiated conditions. The purpose of this study was to determine the effects of various irradiated conditions of Er:YAG laser preparation on the vibration speed of the tooth. Four extracted permanent upper first premolars setup the plaster basement. The experimental periodontal tissue was selected of silicone impression material. The vibration speed and frequency characteristics were analyzed by using a laser Doppler vibrometer. The laser irradiation energy was applied 145 mJ; and the repetition rate examined was 1, 3, 5, and 10 Hz. The water flow rate was set at 5, 10, and 15 ml/min; and distance between irradiation tip and the tooth surface examined was 0 (contact), 0.5, 1, 1.5, and 2 mm. The highest vibration speed was significantly obtained with the following values: 10 Hz, 10 ml, and contact irradiation. These results suggest that other irradiation conditions, in addition to the energy level affect tooth vibration speed and may be linked to preparation efficiency.