Comparison of temperature increase in in vitro human tooth pulp by different light sources in the dental whitening process

This work evaluated the increase in dental pulp temperature caused by different light sources, used in the dental whitening process, following the irradiation protocol from the light manufacturer. Human incisor, canine and premolar teeth were used. A whitening gel made of hydrogen peroxide 35% v/v and a condenser agent were applied to each tooth, on the vestibular surface, and was activated by five different light sources: photo-polymerizer with blue bandpass filtered halogen lamp (HL) (600 mW, λ = 430–480 nm), blue light emitting diode (LED) (BL) (1 W, λ = 470 nm), blue LED associated with infrared diode laser (BL+IL) (120 mW, λ = 795 nm), green LED (GL) (600 mW, λ = 530 nm) and green LED associated with infrared diode laser (GL+IL) (120 mW, λ = 795 nm), with the equipment turned on, an exposure time of 1 min, and resting time of 30 s, repeated three times. The temperature was measured at the beginning and ending of exposure by a digital thermometer (type K thermocouple), placed inside the dental pulp chamber. Analyzing the mean temperature variation that occurred along the irradiation time, we found that the BL and BL+IL group presented the highest temperature variations, mainly in the incisor tooth. The GL and GL+IL presented the lowest temperature increase. The maximum temperature variation reached was 5.5°C for the BL+IL in the incisor tooth. The HL presented a smaller temperature variation than the BL did, but it had a residual temperature when the light was off. The GL and GL+IL promoted a non-significant temperature increase, as low as 1°C, even with total power equal to the that of the HL.