Influence of Different Light-Activated Bleaching Gels on Pulp Chamber Temperature: An In Vitro Study

Background: Significant advances in in-office bleaching treatments have been made by introducing some types of light sources. Halogen lights, LEDs, and diode lasers are the most popular devices used for in-office bleaching. There is a risk that bleaching-activating light sources might increase temperature and have side effects on the dental pulp. This study evaluated the effect of different light-activated bleaching gels on pulp chamber temperature. Methods: In this experimental study, 36 bovine incisor teeth were selected for investigation. The samples were divided into three groups, including Opalescence Xtra Boost PF bleaching gel with the 405 nm LED (group one), Opalescence Xtra Boost PF bleaching gel with 810 nm diode laser (group two), and Heydent bleaching gel with 810 nm diode laser (group three). Bleaching gels with a thickness of 1 mm were applied on teeth surfaces and activated according to the manufacturer’s instructions. The temperature change was recorded every second, and the results of the graph showing the peak temperature were plotted using SPSS software. One-way ANOVA was employed to determine the effect of bleaching type on temperature rise. In case of the presence of a significant difference, post-hoc Tukey’s test was utilized for pairwise comparison of the groups. Results: The temperature rise considerably depends on the light sources. Group one (LED+bleaching gel Xtra boost) had the lowest temperature rise (1.87° C±0.15), while group two (diode laser+bleaching gel Xtra boost) had the highest temperature rise (3.55° C±0.50). There was a statistically noticeable difference in temperature rise among all groups (P<0.05). Conclusion: The light activation of in-office bleaching gels with the diode laser caused higher temperature changes as compared to LED. However, the detected temperature rise was not critical for pulpal health.