A meta-analysis of ozone effect on tooth bleaching

This systematic review assessed the effectiveness of ozone (O(3)) in the color change of in-office tooth bleaching in vital teeth (TB) and the sensitivity control. Only randomized controlled clinical trials were included. Seven databases were used as primary search sources, and three additional sources were searched to capture the "grey literature" partially. The JBI tool was used to assess the risk of bias. TB was assessed using the ΔELab color change metric comparing tooth color pre- and post-bleaching. We meta-analyzed the ΔELab estimates per method and calculated the absolute standardized mean difference using random-effect models. The GRADE approach assessed the certainty of the evidence. The ΔELab estimates ranged from 1.28 when the O(3) was used alone to 6.93 when combined with hydrogen peroxide (HP). Two studies compared O(3) and HP alone, but their TB was similar (SMD = − 0.02; 95%CI: − 0.54; 0.49). The bleaching effectiveness for the combination of O(3) + HP compared to HP was similar (SMD = 0.38; 95%CI: − 0.04; 0.81). Thus, based on the available literature, our findings suggest that O(3) is not superior to the conventional technique using HP on the change of tooth color. The O(3) did not present sensitivity when used alone. When O(3) was used in combination with HP, patients reported hypersensitivity only when O(3) was applied before HP, i.e., no sensitivity was perceived when O(3) was applied after HP.