Comparison of the Bleaching Efficacy of Different Agents Used for Internal Bleaching: A Systematic Review and Meta-Analysis

Abstract

IntroductionThe aim of this study was to analyze and compare the efficacy of different bleaching agents typically used for internal bleaching of endodontically treated discolored teeth. MethodsElectronic databases (PubMed, Web of Science, and Cochrane Library) were searched by 2 reviewers for clinical trials in which the color of endodontically treated discolored teeth before and after internal bleaching was examined using shade guide units (ΔSGU) or a spectrophotometer/colorimeter (ΔE). The efficacies of the bleaching agents were compared using subgroup analyses. Statistical heterogeneity was assessed with the Cochran Q test and I2 statistic. Publication bias was evaluated using funnel plots. ResultsEight studies were included in the systematic review, 6 of which could be included in the meta-analyses. Internal bleaching led to a significant change in tooth shade (ΔSGU: 6.27 [95% confidence interval, 5.36–7.17], ΔE: 12.83 [95% confidence interval, 9.46–16.20]). With regard to ΔSGU, the use of carbamide peroxide (35% or 37%), hydrogen peroxide (35%), and the combination of sodium perborate and hydrogen peroxide (3% or 30%) led to a better bleaching effect than sodium perborate (adjusted P value ≤ .026). Regarding ΔE, there were no significant differences between carbamide peroxide (37%), hydrogen peroxide (35%), and sodium perborate mixed with hydrogen peroxide (P = .051). The risk of bias of the included studies was classified as moderate to high. ConclusionsCarbamide peroxide, hydrogen peroxide, and sodium perborate have a significant bleaching effect on discolored, root canal–treated teeth. For a valid assessment of shade stability and a comparison of bleaching agents and their concentrations, further studies with long-term recalls are necessary.