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.

Bleaching-induced tooth sensitivity with application of a desensitizing gel before and after in-office bleaching: a triple-blind randomized clinical trial.

OBJECTIVES: This randomized triple-blind clinical trial, split-mouth design, evaluated the application effect of the desensitizing gel before and after in-office bleaching on tooth sensitivity. MATERIALS AND METHODS: In one group, the desensitizing gel was applied for 10 min before the bleaching with 35% hydrogen peroxide, and then application of placebo gel after (n = 90). In the other group, the desensitizing gel was applied before and after the bleaching procedure for 10 min (n = 90). The primary outcome was pain intensity assessed with a numeric rating scale and a visual analog scale. Color was evaluated by means of a digital spectrophotometer and a shade guides. RESULTS: The proportion of patients that experienced pain in the side of before application was 90% (95% CI 82 to 94.6%), while the side of before and after was 93% (95% CI 86.2 to 96.9%), without significant difference between groups (OR = 0.25; 95% CI 0.005 to 2.52; p = 0.37). Pain was correlated in both groups, for the NRS scale (p < 0.0001) and the VAS scale (p < 0.0001) in all assessment periods. Significant whitening was detected, and no significant difference of color change was observed between groups (p > 0.45). CONCLUSIONS: The application of the desensitizing agent did not influence the effectiveness of bleaching, but it was not efficient in reducing the sensitivity, when applied before the procedure, or before and after. CLINICAL RELEVANCE: The use of a desensitizing gel before or after in-office bleaching does not reduce incidence or intensity of tooth sensitivity.

Effect of Different Protocols in Preconditioning With EDTA in Sclerotic Dentin and Enamel Before Universal Adhesives Applied in Self-etch Mode.

OBJECTIVES: The aim of this study was to investigate the effect of different protocols of 17% ethylene diamine tetra-acetic acid (EDTA) conditioning on the etching pattern and immediate bond strength of universal adhesives to enamel and sclerotic dentin. METHODS AND MATERIALS: Forty bovine teeth with sclerotic dentin and 20 human third molars were randomly divided into eight groups resulting from the combination of the main factors surface treatment (none, two-minute EDTA conditioning manual application, 30-second EDTA manual application, 30-second EDTA sonic application) and adhesives systems (Scotchbond Universal Adhesive [SBU] and Prime & Bond Elect [PBE]). Resin-dentin and enamel-dentin bond specimens were prepared and tested under the microtensile bond strength (µTBS) and microshear bond strength (µSBS) tests, respectively. The etching pattern produced on the unground enamel and the sclerotic dentin surfaces under the different protocols and adhesive systems was evaluated under scanning electron microscopy. RESULTS: For enamel, only the main factor adhesive was significant (p<0.0001), with SBU showing the highest µSBS. In sclerotic dentin, the lowest mean was observed for the group without EDTA application and the highest mean in the group with EDTA application with the sonic device for 30 seconds. Regardless of the EDTA protocol, the highest means of µTBS were observed for SBU (p<0.05). CONCLUSIONS: EDTA conditioning improves the bonding performance of universal adhesives in the self-etch mode on sclerotic dentin, mainly when applied for 30 seconds with the aid of a sonic device. EDTA pretreatment also improves the retentive etching pattern of enamel, but it does not result in higher enamel bond strength.