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Objective This randomized clinical trial evaluated the effectiveness and tooth sensitivity (TS) of 37.5% hydrogen peroxide (37.5HP) in‐office bleaching with reduced protocol. Materials and methods Forty participants with shade mean C2 or darker for the six maxillary anterior teeth were randomly allocated into two treatment groups (n = 20): two (37.5HP2) or three (37.5HP3) 8 min applications/clinical session. Three clinical sessions were performed with a 1 week interval. Color evaluations were done with a spectrophotometer at baseline and 1 week post‐bleaching. TS was measured during and up to 48 h after bleaching using a five‐point numeric rating scale. Color change was evaluated by Student's t‐test for independent samples. The absolute risk and intensity of TS were analyzed by Fisher's and Mann–Whitney/Friedman tests (p < 0.05). Result Both treatment groups resulted in a significant tooth whitening 1 week post‐bleaching (p < 0.001). There were no significant differences between 37.5HP2 and 37.5HP3 for ΔE*ab, ΔE00 and ∆WID. Also, there were not differences between groups regarding high absolute risk (p = 1.0) and low intensity of TS at all time assessments (p > 0.7). Conclusions The in‐office bleaching with two 37.5% HP applications produced the same whitening degree, risk and intensity of TS to that performed with three gel applications. Clinical significance Clinicians should opt to use a neutral 37.5% HP in‐office bleaching gel for two 8 min applications/clinical session because produces the same whitening effectiveness, risk and low intensity of TS as the protocol proposed by manufacturer (three 8 min applications).

Introduction. Universal single-shade composite resins are characterized by a property that enables the creation of restorations that mimic tooth structure to the extent possible with fewer shades of color. Objectives. This study aimed to instrumentally and visually evaluate the color correspondence of two single-shade composite resins in extracted human teeth multishade composite resins. Methods. Upper central incisors and upper and/or lower molars with intact buccal surfaces were selected. The study consisted of a control group (n = 20): Z250 XT (3M ESPE) (G1) multishade composite resin in colors A1 to A4, and a test group (n = 20) divided further into two equal groups, consisting of single-shade composite resin Omnichroma (Tokuyama Dental) (G2) and single-shade composite resin Vittra APS Unique from (FGM) (G3). Instrumental evaluation was performed using a spectrophotometer, and visual evaluation was performed by three observers. Descriptive measurements related to the differences in color obtained through instrumental means were analyzed using mean and standard deviation, wherein the means were compared using ANOVA, applying the Bonferroni post hoc test. Results. A statistically significant difference was observed among the groups (G1, G2, and G3) (ANOVA: p < 0.001 ). For the visual assessment, regardless of the assessment group, 77.49% of the teeth were within the acceptable color-match classification, with the single-shade resins showing better correspondence than the multishade resins. Conclusion. Single-shade composite resins showed different color-matching results when compared to multishade resins, both in spectrophotometry and visual evaluations. Clinical Significance. Single-shade composite resins simplify the shade-selection process and are promising materials for use in dental practice.

This in vitro study evaluated the effect of 35% hydrogen peroxide (35HP) gels with different desensitizing agents on color, microhardness and roughness of bleached enamel. Forty enamel-dentin specimens (6x6x2 mm2) were obtained from twenty human molars. After color measurement with a spectrophotometer, the specimens were randomized into four groups (n= 10): 35HPw- 35HP without desensitizing agent; 35HPCa- 35HP with calcium; 35HPK- 35HP with 0.5% potassium nitrate; 35HPTFa- 35HPw + topical application of 5% potassium nitrate and 2% sodium fluoride (TFa). Specimens were evaluated for color (∆Eab* and ∆E00), Vickers microhardness (VHN) and, superficial and volumetric roughness (Ra and Sa, µm) using a 3D non-contact profilometer before and 1-week after bleaching. Data were analyzed by ANOVA and Tukey tests (p< 0.05). Both treatment groups promoted a significant whitening effect and there was no difference between them for any color parameters evaluated. All groups reduced significantly the VHN, but the 35HPK showed a reduction significantly major than the other groups. 35HPCa and 35HP+TFa did not avoid the of Ra and Sa increasing. It can be concluded that 35HP bleaching gels with different desensitizing agents did not affect the whitening efficacy. However, all treatments decreased the microhardness, the addition of calcium into 35HP gel and the application of TFa before bleaching did not revert the enamel roughness under in vitro conditions.