Topical application of a desensitizing agent containing potassium nitrate before dental bleaching: a systematic review and meta-analysis.

OBJECTIVES: To conduct a systematic review and meta-analysis to evaluate the risk and intensity of tooth sensitivity (TS) after topical application of desensitizers containing potassium nitrate before dental bleaching. METHODS: We searched PubMed, Scopus, Web of Science, LILACS, BBO, Cochrane Library, and SIGLE. We also surveyed gray literature without restrictions. We meta-analyzed the data using the random-effects model to compare potassium nitrate and placebo in terms of risk and intensity of TS and color change (∆SGU or ∆E). The quality of the evidence was rated using the GRADE approach. The risk of bias (RoB) of the included studies was analyzed using the Cochrane RoB tool. RESULTS: After the database screening, 24 articles remained. A significant 12% lower risk for the groups where desensitizing agents were applied (p = 0.02), with a risk ratio of 0.88 (95% CI 0.78 to 0.98). About the intensity of TS, a significant average mean difference of - 0.77 units of VAS units (95%CI - 1.34 to - 0.19; p = 0.01) in favor of the desensitizer group. In the NRS scale, a significant average mean difference of - 0.36 (95% CI - 0.61 to - 0.12; p value = 0.004) in favor of the desensitizer group. No significant difference was observed in color change (p > 0.28) in ∆SGU and ∆E. CONCLUSIONS: Although a significant reduction in the risk and intensity of TS was observed in groups treated with a potassium nitrate at some point during the bleaching, the clinical significance of this reduction is subtle and clinically questionable. Color change is not affected by the use of agents. CLINICAL RELEVANCE: The reduction in the risk and intensity of TS with the topical application of potassium nitrate-based desensitizing agents in dental bleaching is subtle and maybe clinically questionable.

One-year follow-up of at-home bleaching in smokers before and after dental prophylaxis.

OBJECTIVE: This clinical study evaluated the color longevity after one-year of at-home bleaching with 10% carbamide peroxide (CP) in smokers and nonsmokers. METHODS: Sixty patients, 30 smokers and 30 non-smokers were subjected to bleaching with 10% CP during three hours daily for three weeks. The color was measured at baseline and one week, one month and one year after the completion of dental bleaching using the spectrophotometer Vita Easyshade (ΔE*), shade guide Vita classical organized by value and Vita Bleachedguide 3D-MASTER (ΔSGU). In the one-year recall, the color was assessed before and after dental prophylaxis with Robinson brush and prophylaxis paste. Data from color evaluation were analyzed by two-way repeated measures ANOVA and Tukey's test for the contrast of means (α=0.05). RESULTS: Twenty-seven smokers and 28 non-smokers attended the one-year recall. For both study groups, only the main factor assessment time was statistically significant for ΔSGU (Vita classical) and ΔE* (p<0.001). Effective whitening was observed for both groups at baseline, which was stable at one-month and one year after dental prophylaxis. A slight darkening was observed after one year when the color was measured without prophylaxis. For the Vita Bleachedguide 3D-MASTER, color rebound was observed irrespectively of dental prophylaxis. CONCLUSION: The bleaching with 10% CP remained stable in both groups as long as extrinsic stains from diet and cigarette smoke were removed by professional dental prophylaxis. CLINICAL TRIALS REGISTRY: NCT02017873. CLINICAL RELEVANCE: The results of this study indicate that the bleaching is effective in smokers even after one-year, but dental prophylaxis may be necessary to remove extrinsic stains caused by diet and smoking.