Method: Seventy seven patients with right superior canine darker than A3 were selected to participate in this single-blind randomized trial. The participants were distributed in four groups: bleaching with 35% HP alone; 35% HP + LED/LASER; 20% HP alone and 20% HP + LED/LASER. The buccal surfaces of the anterior teeth were bleached, in two sessions, using a 35% (Whiteness HP Maxx, FGM) or 20% HP gel (manipulated by FGM) with one week interval. At each session, three applications of 15 min were used. For the light activated group, the LED/LASER energy (Whitening Laser Light Plus, DMC) was employed according to the manufacturer’s instructions. The color change was evaluated by using the VITA Classical Shade Guide and the VITA Easyshade Spectrophotometer (Vita Zahnfabrik). Participants recorded TS with a five-point verbal and VAS scales. Color change was analyzed by ANOVA and Tukey’s tests (α=0.05). The absolute risk of TS and TS intensity evaluated by Fisher’s exact test and Kruskall Wallis test, respectively (α= 0.05).
Result: All groups achieved the same level of whitening, except for the 20% HP group, which showed lowest amount of whitening as detected by the subjective evaluation. The use of light did no increase TS during and after bleaching.
Conclusion: The use of LED/laser light activation was able to increase the amount of whitening produced with the 20% HP without increasing TS, but this association was not useful for the 35% HP gel.