aim of this study was to assess the dental bleaching efficacy of 37.5%
hydrogen peroxide (HP), with and without light activation, in HP-exposed
and unexposed areas.
bovine teeth were selected and divided into two groups (n = 14). Crowns
were detached and stained with tea. The gingival half was covered with a
gingival barrier. In the incisal half, 37.5% HP (Pola Office+, SDI) was
applied three times, with a 1-week interval between applications. In
HP-A group, the bleaching agent was activated for 3 min with a LED lamp.
No light activation was applied in HP-N group. Dental color variation
was determined through a spectrophotometer in both halves. Statistical
analysis between groups was performed with an ANOVA test, and intragroup
differences were evaluated, with an ANOVA test for paired data, with a
significance level of P < 0.05.
increase in lightness and a decrease in chroma were found in both
groups and halves. No significant differences in ΔE between groups (P
> 0.5) were detected in the incisal half. After treatment, a
significantly higher ΔE was found in the gingival half for HP-A group (P
< 0.05). For the same group, a significantly higher bleaching effect
was found in the gingival half, compared with the incisal half (P <
activation did not have a significant effect in terms of bleaching in
the incisal half, but increased clearance in the gingival half.
light activation does not significantly increase the whitening effect,
but it can improve the bleaching diffusion to areas where it has not
been directly applied.