Bleaching efficacy of in-office dental bleaching with different application protocols: a single-blind randomized controlled trial

Objective This randomized controlled trial aimed to evaluate the equivalence in the color change, adverse effects, self-perception (AS) and the impact on oral condition (IO) of participants submitted to different application protocols of in-office dental bleaching. Materials and methods 165 participants were bleached with a 35% hydrogen peroxide gel (Total Blanc Office One-Step, DFL), according to the following protocols: (1) 2 applications of 20-min each (2 x 20 min); (2) 1 x 40-min and; (3) 1 x 30-min. The color change was evaluated with the Vita Easyshade spectrophotometer, Vita Classical and Vita Bleachedguide scales. The intensity and risk of tooth sensitivity (TS) and gingival irritation (GI) were recorded using a 0-10 visual analogue scale (VAS). AS and IO was assessed before and after the bleaching procedure using the Orofacial Aesthetic Scale and Oral Health Impact Profile-14, respectively. Results Equivalent color change were observed (p < 0.001), with no significant difference between groups. The group 2 x 20 min presented the highest risk of TS (76%, 95% CI 63 to 85), compared to the 1 x 30 min (p < 0.04). The intensity of TS and GI and the risk of GI was similar between groups (p > 0.31). Irrespectively of the group (p = 0.32), significant improvements were observed for all items of AS and IO after bleaching (p < 0.02). Conclusions The 1 x 30 min protocol produced equivalent color change to the other bleaching protocols with reduced risk of TS and shorter application time.