Evaluation of Different Protocols with 4% Hydrogen Peroxide in Bleaching Efficacy and Tooth Sensitivity - A Single-blind, Randomized Clinical Trial.

OBJECTIVES: To compare the bleaching efficacy and tooth sensitivity (TS) of 4% hydrogen peroxide (HP) in adults using a continuous or fractioned protocol. METHODS AND MATERIALS: A single-blind randomized controlled trial with a parallel design was conducted. Eighty-six patients with upper canines A2 or darker were submitted to bleaching with 4% HP gel for three weeks after random allocation into the fractioned protocol (two 30-minute daily applications) or continuous protocol (single one-hour application). We evaluated the color change at baseline, weekly, and 30 days after the bleaching using Vita Classical and Vita Bleachedguide using the units of shade guides (SGU) and by spectrophotometer using CIELab 1976 (ΔEab) and CIEDE 2000 formulas (ΔE00), as well as Whiteness Index (ΔWID). We assessed the absolute risk of TS with a visual analog scale (VAS) and numeric rating scale (NRS). Color changes in each recall were compared with the Student t-test. The risk of TS was evaluated by the Chi-square test, and the intensity by Mann-Whitney test (NRS) and Student t-test (VAS). RESULTS: The mean difference for the ΔSGU Vita Classical (0.5; 95% CI: -0.5 to 1.5), ΔSGU Vita Bleachedguide (-0.4; 95% CI: -1.5 to 0.7), ΔEab (1.4; 95% CI: -0.1 to 2.9), ΔE00 (0.6; 95% CI: -0.4 to 1.6), and ΔWID (-3.2; 95% CI: -7.3 to 0.9) after three weeks of bleaching was not clinically or statistically significant (p>0.10). The absolute risk of TS was 44% (95% CI: 30-58%) and 46% (95% CI: 32-61%) in the fractioned and continuous protocols, respectively (RR=1.0; 95% CI: 0.6 to 1.5; p>0.91). CONCLUSION: A fractioned bleaching protocol with 4% HP (30 minutes twice daily) did not increase the whitening degree nor affect the risk and intensity of TS when compared with the one-hour continuous protocol.

Five-year Randomized Clinical Trial on the Performance of Two Etch-and-rinse Adhesives in Noncarious Cervical Lesions.

OBJECTIVES: To evaluate the 5-year clinical performance of two-step etch-and-rinse adhesives in noncarious cervical lesions (NCCL). METHODS AND MATERIALS: The sample comprised 35 adults with at least two similar-sized NCCL. Seventy restorations were placed, according to one of the following groups: Adper Single Bond 2 (SB) and Ambar (AM). The restorations were placed incrementally using a resin composite (Opallis). The restorations were evaluated at baseline and after 6 and 18 months and 5 years using some items of the FDI criteria. The differences in the ratings of the two materials after 6 months, 18 months, and 5 years were performed with Friedman repeated measures ANOVA by rank and McNemar test for significance in each pair (α=0.05). RESULTS: Five patients did not attend the 60-month recall. No significant differences were observed between the materials for any criteria evaluated. Twenty-one restorations failed (12 for SB and 9 for AM) after 60 months. Thus, the retention rate for SB at 60 months were 55.6% for SB and 71% for AM (p=0.32). After 60 months, 12 restorations (6 for SB and 6 AM) showed some loss of marginal adaptation (p=1.0). Slight marginal discoloration was observed in 10 restorations (6 for SB and 4 AM; p=0.91). Five restorations (2 for SB and 3 for AM) showed recurrences of caries (p=1.0). CONCLUSIONS: Both two-step etch-and-rinse adhesives-Adper Single Bond 2, a polyalkenoic acid-containing adhesive, and Ambar, a 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-containing adhesive-showed acceptable clinical performance after 60 months.

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.