The temperature effects of diode laser on pulpal tissues for the teeth whitening treatment

Abstract

Teeth are important organ of human body. Nowadays, people are more interested in dental care, especially, with teeth whitening. The latest development in this treatment is the use of laser diode. The laser process provides many advantages include a shorter treatment time, the reduction of tooth sensitivity and gingival irritation. However, a critical concern still exists, i.e. the destruction of the pulpal tissues due to the heat generated during the treatment. So the purposes of this research then include not only the changing of teeth color but also the temperature changing in pulpal tissues as a function of the power density of the laser diode. In the experiment, human-extracted teeth samples coated by 38 hydrogen peroxide were stimulated with 10.9, 16.1 and 36.7 W/cm 2 of a 808 nm laser diode. The exposure time of 60 seconds for a single-exposure and two of 30 seconds for double-exposure of were studied. The teeth color before and after the treatment were described by the CIE L*a*b* system. The results showed that the high power density (36.7 W/cm 2 ) had given more luminous teeth than the low power density. However, the high power density of the laser also created the high temperature in the pulpal tissue. The power density of 16.1 W/cm 2 was the highest power allowable before reaching the temperature safety limit for pulpal tissue. In addition, irradiation of laser diode with the double-exposure of 30 seconds created more luminous and less heat than that of the single exposure of 60 seconds. © 2010 Published by Elsevier Ltd.