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This study evaluated the influence of thermo-mechanical cycling (TMC) on the bond strength (BS) of a universal adhesive system (UAS -Adper Single Bond Universal, 3M ESPE) to dentin treated or not with 0.2% chlorhexidine (CHX). Methods: Eighty human molars were flattened until reach the dentin and separated into 4 groups according to the bonding protocol: ENR Group: 37% phosphoric acid þ 3-step etch-and-rinse adhesive system (ENR); UAS Group:After treatments, teeth were restored (Filtek Z350, 3M ESPE). Samples (n ¼ 10) were submitted to aging process: stored in distilled water at 37 C/30 days or TMC (ERIOS -98N/1.6Hz þ thermal cycling 5/37/ 55 C -1,200,000 cycles). Specimens were sectioned into sticks (1.0 mm 2 ) and submitted to the microtensile test (Mechanical Test Machine -0.5 mm/min). Fracture patterns and hybrid layer integrity were analyzed under Stereomicroscope and Scanning Electron Microscopy (SEM). Results:The BS results (3-way ANOVA, Bonferroni's test, α ¼ 5%) showed that groups treated with CHX presented higher BS values than control groups; significant in all cases (p < .05), except for ENR submitted to TMC (p > .05). When CHX was applied and samples were cycled, UAS revealed higher BS (p < .05) than ENR. After TMC, cohesive fractures increased for UAS, regardless of CHX application. SEM analysis demonstrated different hybridization patterns for the adhesive systems tested. Conclusion:The performance of the universal adhesive system used in self-etch mode was better than that of the 3step etch-and-rinse adhesive system. Clinical significance: Universal adhesive systems have been developed in order to simplify the dentin hybridization protocol. It is important to determine the longevity of the adhesive interface using these bonding materials after chewing.

Objective: To evaluate the protective effect of phytosphingosine (PHS) against staining on dental enamel. Materials and Methods: Ninety-six specimens of bovine teeth (6 mm × 6 mm × 2 mm) were cut, and initial color (Easyshade, VITA), microhardness (HMV-2, Shimadzu) and fluorescence (Matlabs software, Matworks) measurements were performed. Specimens were separated into four groups according to the treatments: Distilled water (control); Human saliva (HS); PHS; PHS + HS. Specimens (n = 6) were submitted to staining procedures: Distilled water (immersion for 30 days-control); Coffee (15 minutes, twice a day/for 15 days); Black tea (as described for Coffee) and cigarette smoke (20 cigarettes/sample). Final measurements were performed, and data were analyzed (Color-CIEDE2000, fluorescence-2-way ANOVA, Tukey, and microhardness-Kruskal-Wallis Dunn, P < .05). Results: Coffee caused the highest color change (ΔE 00), followed by black tea, regardless of the treatment employed. Distilled water and cigarette smoke produced similar color changes (P > .05) for the groups control (water = 1.0 + − 0.5/ cigarette = 2.3 0.3) and PHS (water = 0.8 0.4/ cigarette = 2.3 0.4). PHS + HS demonstrated intermediate means than PHS and HS when stained with coffee and tea. After treatments, the least fluorescence alterations occurred for the groups treated with distilled water and cigarette, regardless of the treatment, with no difference (P > .05) between them. There was a significant difference (P < .05) on microhardness between all the groups, as PHS + HS > PHS > HS > Distilled water. Conclusions: It was concluded that PHS treatment did not protect the staining of the enamel by coffee and tea, but increased the microhardness, both in the presence and absence of a salivary pellicle. Practical Implications: Phytoshingosine is a novel agent and considered a promising component for anti-biofilm and anti-erosion properties by the formation of a diffusion barrier on the dental enamel. In line, PHS might be considered for anti-staining purposes.

Objective This study evaluated the influence of over‐the‐counter agents on the maintenance of color and microhardness of the enamel after home bleaching protocol. Materials and methods Specimens of bovine teeth (6 × 6 × 2 mm) were prepared, and color (Easyshade, VITA) and microhardness (HMV‐2, Shimadzu) readings were performed. All the specimens were bleached using 22% carbamide peroxide (22%CP), except for the control group, and then separated into seven groups (n = 10) according to the interaction of toothpaste (whitening, conventional, and whitening with peroxide) and mouth rinse (whitening and conventional). The study simulated 1 year of toothbrushing (Pepsodent, MAVTEC) and mouth rinse by immersion. After that, final color and microhardness measurements were performed. Data were analyzed by one‐way ANOVA, Tukey's test (P < .05). Results The group submitted to 22%CP + whitening toothpaste + whitening mouth rinse showed higher color maintenance (P < .05) than the control group. The perception of whitening of teeth (ΔWID) was higher than the color change (ΔE00). There was a decrease in microhardness after treatment with 22%CP + conventional toothpaste + whitening mouth rinse. Conclusions Over‐the‐counter products can help with the maintenance of tooth whitening after bleaching with carbamide peroxide; however, special attention should be given since the association of products can also reduce the microhardness of the dental enamel. Clinical significance The association between whitening toothpastes and mouth rinses might be beneficial for maintaining color during 1 year after bleaching treatment.

The objective of this study was to evaluate the effect of natural bleaching products on the color, whiteness, and superficial properties of dental enamel. Seventy fragments of bovine teeth were obtained (6mm x 6mm x 2mm). Initial surface roughness (Surfcorder SE1700, Kosakalab), microhardness (HMV-2, Shimadzu), color (EasyShade, VITA), and surface gloss (Micro-Gloss 45º BYK, Gardner) readings were done. Samples were separated into five groups (n=14) according to the treatments used: CT-conventional toothpaste (negative control); CH-charcoal; TU-turmeric; BP-banana peel, and CP16%-16% carbamide peroxide gel (positive control, 4 h/day for 14 days), and then brushed for 560 cycles (T1) and 1200 cycles (T2), equivalent to 14 and 30 days of brushing. New measurements were performed after T1 and T2. The whiteness index for dentistry change (∆WID) and Weight loss (Wl) were calculated. CP16% demonstrated the highest (p<.05) color change (ΔE00) and ∆WID (2-way ANOVA, Bonferroni, p<.05). Surface gloss alterations were lower for TU, CP16%, and BP. CT and CH increased surface roughness (p<.05). CP16% decreased enamel microhardness. CH presented medium abrasiveness, and CT and TU, low abrasiveness. The popular bleaching products were not efficient for tooth whitening. Furthermore, brushing with charcoal increased the enamel surface roughness, and CP16% decreased enamel microhardness over time