Effect of a pulsed Nd:YAG laser on surface acoustic wave velocity of human dental enamel

The purpose of this study was to evaluate the effect of Nd:YAG laser irradiation on the phase velocity of surface acoustic waves (SAWs) of human enamel. A pulsed Nd:YAG laser at 1064 nm wavelength was used to irradiate the human enamel from extracted human premolars. The output power and repetition rate were 250 mJ and 5 Hz, respectively. The SAW phase velocities before and after laser irradiation were determined using a laser photoacoustic method. The laser-treated enamel surface exhibited a higher velocity value for frequencies higher than 3 MHz. The result of this study suggests that there is an important correlation between the elastic properties of human enamel and the pulsed Nd:YAG laser fluence, which increases the SAW phase velocity, and this may help shed some light on the mechanism of laser treatment in dental research.