Abstract

--- - "Background: Bleaching protocols using low concentration hydrogen peroxide (HP) photoactivated with LED sources have been widely discussed. Herein, we evaluated the whitening efficacy of 15% HP photoactivated with blue or violet LED compared to 35% HP." - "Methods: Thirty bovine crowns were sectioned into 5 x 5 x 2 mm specimens. After staining in black tea, the specimens were randomized into three groups (n = 10): 35% HP, 15% HP + blue LED and 15% HP + violet LED. Two bleaching sessions were performed and the color assessment (Delta L*, Delta a*, Delta b*, Delta E-ab [CIELab], Delta E-00 [CIEDE2000] and WID) was performed before, 24h after each session, 7 days and 1 month after the last session. Data were evaluated by two-way repeated measures ANOVA and Bonferroni post-test at a significance level of 5%." - "Results: All groups showed effective and similar results over 1 month of follow-up (p >0.05), with only intra-group differences among the time intervals (p < 0.05)." - "Conclusions: The use of 15% HP photoactivated with blue or violet LED showed similar whitening efficacy compared to 35% HP. Thus, the association of low concentration bleaching gels with blue or violet LED sources can provide successful and less-aggressive treatment in terms of color change."