Avaliação de protocolos de clareamento através de ensaios clínicos randomizados, revisões sistemáticas e meta-análises

Abstract

To evaluate efficacy and tooth sensitivity (TS) through the use of desensitizing agents incorporated into the gel in the at-home (1) and in the in-office bleaching (2), in the use of light activation in the in-office bleaching with high and low hydrogen peroxide concentration (3 and 4); in combined (at-home and in-office) vs. isolated bleaching (5), in addition to assessing the conformity of the randomized clinical trials (RCTs) of bleaching with CONSORT and the risk of bias of these studies by the Cochrane tool (6). Methodologies: Six studies: two RCTs and four systematic reviews (SRs) were made for this work, the study (4) was a mixed-treatment comparison (MTC). The RCTs (1 and 2) were triple-blind, split-mouth and the bleaching treatment was performed on 120 caries-free patients, according to inclusion and exclusion criteria, of which 60 were in each study. The desensitizing agents incorporated into the gel were 3% potassium nitrate and 0.2% sodium fluoride (1), and 5% potassium nitrate in study (2). In study (1) a tray was used three hours daily for 21 days, in study (2) a single application of 50 minutes was made in two sessions with 7-days intervals between them. Were assessed the absolute risk and the intensity of TS using the 0-10 cm visual analog and 0-4 numerical rating scales for 21 days in the study (1) and during 48 hours after each study session (2); the color change was recorded using the Vita Classical, Bleachedguide (ΔSGU) and Easyshade spectrophotometer (ΔE*) color scales before, during and after 30 days of the end of each treatment. The absolute risk and intensity of TS were assessed by the McNemar and Wilcoxon Signed Rank tests, respectively (α = 0.05), the color change was assessed by Wilcoxon Signed Rank (ΔSGU) and t-test for paired data (ΔE*) (α = 0.05). In the SRs (3-6) were searched for specific terms about the topic on databases and grey literature. The risk of bias was assessed using the Cochrane Collaboration tool. Meta-analysis were conducted for color change (ΔE*, ΔSGU), risk and intensity of TS using random effects model. Heterogeneity was assessed with the Cochran Q test and the I2 statistic. The quality of evidence (GRADE) was evaluated in the studies (3) and (5). Results: In the study (1), there were no differences between groups in color, risk and intensity of SD (p > 0.05); in the study (2) differences were observed only in the reduction the intensity of TS for the group with desensitizing agent in the first 24 hours (p < 0.01). In the SRs after the search of the studies, there were 21 (3), 28 (4), 11 (5), 185 (6) RCTs. In SR (3) there were no differences in color and TS (p > 0.05), and the quality of evidence was graded as moderate for ΔE* and risk of TS, and very low and low for ΔSGU and intensity of TS, respectively. In MTC SR (4), there were no differences in color without the use of light or with different light sources used. In SR (5) there was no difference in color in the combined vs. in-office bleaching (p > 0.05), and no data were available to assess the risk and intensity of TS; in combined vs. at-home bleaching no differences were observed for ΔE*, ΔSGU and risk of TS; however, lower intensity of TS was detected in the sole at-home bleaching with a standardized mean difference of 0.86 (95% CI, 0.31-1.41); and the quality of evidence was graded as moderate for color change in ΔE*, and low or very low for the other analysis. In the SR (6) in the CONSORT classification of the studies, the general mean was 16.7 ± 5.4 points (out of 32 points in total) and only 7.6% were judged as low risk of bias. Conclusions: The incorporation of the desensitizing agents in the bleaching gels used in this study did not affect the color and did not reduce the TS in the at-home bleaching (1), but it decreased the intensity of TS in the in-office bleaching (2). The use of light activation in the in-office bleaching did not improve color or affect TS regardless of the concentration of hydrogen peroxide used (3) and also did not affect color in the study (4). In combined vs. isolated bleaching (5), low intensity of TS was found in sole at-home bleaching. And in the study (6) it was concluded that adherence to CONSORT in RCTs of different bleaching techniques is low and with high risk of bias.