What is the optimal concentration of carbamide peroxide for at-home bleaching? A systematic review and network...

This study represents the first network meta-analysis (NMA) comparing the efficacy and safety of different concentrations of carbamide peroxide (CP) for at-home bleaching in permanent dentition. A comprehensive search was conducted across PubMed, Cochrane Central, LILACS/BBO, SCOPUS, Web of Science, EMBASE, and gray literature. Randomized controlled trials (RCTs) comparing at least two CP concentrations were included. Color change (ΔE, ΔSGU), risk and intensity of tooth sensitivity TS was assessed Cochrane RoB 2.0 and GRADE were used to evaluate the risk of bias (RoB) and certainty of evidence. Thirteen RCTs were included, most with high RoB. CP5 % and 37 % appeared in a single trial each. For ΔSGU, no significant differences were detected between concentrations. For ΔE, all concentrations were superior to CP 5 %, with the largest difference observed for CP 37 %; intermediate concentrations showed minimal variations. Regarding TS, CP10 % was associated with a 67 % lower risk compared to CP 20-22 % (RR 1.67; 95 % CrI: 1.15-2.57), and CP 20-22 % also caused significantly higher TS intensity on the NRS scale. Conclusion: Lower concentrations of CP reduced the risk of TS while achieving bleaching efficacy comparable to higher concentrations, suggesting that less concentrated gels is safer and effective for at-home bleaching.