SUMMARY
Objectives: Light irradiation and heat have been used to accelerate the process of tooth bleaching. This study aimed to assess the efficacy of conventional bleaching compared to laser-bleaching using three different wavelengths of diode lasers.Materials and Methods: In this in-vitro experimental study, 40 extracted human central incisors were immersed in a coloring solution made of tea, coffee, and cola for 21 days. The L*, a*, and b* color parameters were measured before and after the immersion using spectrophotometry. The teeth were then randomly divided into four groups (n=10) as follows: group 1: 810-nm diode laser + Biolase Laser White 20, group 2: 940-nm diode laser + Biolase Laser White 20, group 3: 980-nm diode laser + Biolase Laser White 20, and group 4: conventional bleaching with Opalescence Boost without laser irradiation. One-way analysis of variance (ANOVA) was used to assess the effect of laser type and bleaching technique on color parameters.Results: The 940-nm (?E=28.5896) and 810-nm laser groups (?E=21.2382) showed the highest and the lowest bleaching efficacy, respectively; however, the groups were not significantly different in terms of bleaching efficacy (P>0.05).Conclusion: Laser-bleaching with 810-, 940- and 980-nm wavelengths of diode laser has an efficacy similar to that of conventional bleaching but in a shorter period. No difference was noted between different laser wavelengths in terms of bleaching efficacy.