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.
This study evaluated the stain resistance and surface roughness alteration of a CAD/CAM processed hybrid ceramic. Specimens were fabricated: 30 of resin‐based composite (RBC; Filtek Z350), 30 of ceramic (IPS emax Press) and 60 of hybrid ceramic (Lava Ultimate). Color, translucency (BYK Gardner), whiteness index for dentistry (WID) and surface roughness (Surftest SJ‐201P) measurements were made. Samples were randomly separated into three groups: Coffee staining (3 hours/day), coffee staining + mechanical toothbrushing (3 hours/day‐staining + 40 cycles‐toothbrushing) and storage in distilled water (control), all for 30 days Afterwards, all specimens were polished: RBC (n = 10) with a composite polishing kit (Enhance Dentsply), ceramic (n = 10) with a ceramic one (Eve Diapol), half of the hybrid ceramic (n = 10) with the composite polishing kit and the other half (n = 10) with the ceramic kit. Then, final readouts were obtained. Data was analyzed by two‐way analysis of variance. The hybrid ceramic exhibited intermediate color change after staining (P < .05). The hybrid ceramic presented WID chance similar to ceramic in control group (P > .05). After staining/brushing, the hybrid ceramic polishing with the ceramic kit revealed the greatest translucency change (P < .05). RBC and hybrid ceramic polishing with the resin kit presented similar surface roughness alteration (P > .05), except after staining/brushing (P < .05). Also, ceramic was different from the hybrid ceramic polishing with the ceramic kit (P < .05). The hybrid ceramic showed intermediate staining and roughness compared to the RBC and the ceramic. The ceramic polishing kit was more effective in removing stains from the hybrid ceramic.
The aim of this in situ study was to evaluate color change, surface roughness, gloss, and microhardness in tooth enamel submitted to whitening and remineralizing toothpastes. Fifteen healthy adults (REBEC - RBR-7p87yr) (with unstimulated salivary flow ≥ 1.5 ml for 5 minutes, pH=7) wore two intraoral devices containing four bovine dental fragments (6 x 6 x 2 mm). Participants were randomly assigned and instructed to toothbrush the devices with the tested toothpastes (30 days): CT: conventional; WT: whitening; WTP: whitening with peroxide, and RT: remineralizing toothpaste. A washout period of 7 days was established. Readouts of color, gloss, surface roughness, and microhardness were performed before and after brushing. The results demonstrated no color, gloss, and microhardness differences (p>0.5). The samples brushed with WTP (0.2(0.7) showed higher surface roughness (p=0.0493) than those with WT (-0.5(1.0). The toothpastes did not alter the properties of the dental enamel, except for the roughness. Toothpaste with an abrasive system based on sodium bicarbonate and silica, and that contains sodium carbonate peroxide increased the surface roughness of the enamel.
Objective. This study evaluated, in vitro and in situ, the effect of phytosphingosine (PHS) associated with toothbrushing regarding color stability, surface roughness, and microhardness.Methods. Sixty-four specimens of bovine teeth (6x6x2 mm) were separated in 8 groups (n=8): S+TB: PHS (spray) + toothbrushing; TB+S: toothbrushing + PHS (spray); I+TB: PHS (immersion) + toothbrushing; TB+I: toothbrushing + PHS (immersion); TB: toothbrushing; S: PHS spray; I: immersion in PHS solution and Saliva: immersion in saliva. Toothbrushing simulation (Mavtec, Brazil) was performed (356 rpm, 3.8 centimeters course by the toothbrush -Soft Tek) for 1, 7, 15, and 30 days. PHS remained in contact with specimens for 15 minutes. The specimens were evaluated before and after toothbrushing for color alteration (Easy Shade, VITA), surface roughness (Model SJ-201P Mitutoyo), and Knoop microhardness (HMV-2, Shimadzu Corporation). For the in situ analyses, 8 participants were recruited and received an intraoral device with 6 fragments of bovine enamel (6x6x2 mm). The properties evaluated were the same as those of the in vitro study. Participants were randomized following best results of in vitro tested protocols, for 15 days: TB; TB+S; I+TB. Data obtained by in vitro (two-way ANOVA, Tukey, p <.05) and in situ (one-way ANOVA, Tukey, p <.05) studies were analyzed.Results. The in vitro study showed a greater color change was found after 30 days. The greatest differences in surface roughness occurred between the initial value and after 1 day. Regarding microhardness, the highest values occurred after 15 and 30 days, which were similar. The in situ study showed greater color changes for the TB and I + TB, and greater surface roughness changes for TB and a similar increase in microhardness for the PHS protocols, which were higher than TB.Conclusions. Phytosphingosine leads to an increase in performance regarding color stability, surface roughness, and microhardness when applied. In general, the application of PHS after brushing showed a positive impact on its performance. Clinical relevance. Phytosphingosine showed to be interesting to compound prevention formulations in the dentistry eld.Toothbrushing with toothpaste, responsible for removing surface adhered substances, including extrinsic stains and bio lms, could also interfere in the e ciency of any previous treatment. Although strong evidence underlines the long-term protective effects of PHS coatings for at least 16 h after application [5], there is no report of the long-term sustainability of PHS on the enamel after daily toothbrushing. It is envisaged that its sustainability on the enamel surface after toothbrushing is important since the literature demonstrates changes in the surface roughness of the dental substrate by various products used in dentistry, such as toothpaste and oral hygiene solutions [20][21][22][23].Solutions are often applied by immersion or spray to facilitate their use and decrease the amount of solution needed for antimicrobial action [24]. However, for PHS, the ...
The present study compared the effectiveness of brushing and over-the-counter tooth-whitening strips on stain removal. Forty bovine teeth were used. Initial color readings were taken, and half of the samples were stained with grape juice for 7 days. The others teeth were used as the control. Both stained and control teeth were randomly separated into 2 groups (n=10) according to the treatment they underwent: whitening strips 2 times/day for 30 minutes for 7 days and mechanical brushing for 1 year using toothpaste. After treatments, new color readings were taken and results of color stability (ΔE) and changes in coordinates (ΔL, Δa, Δb) were statistically analyzed (2-way ANOVA, Bonferroni p<.05). Statistical differences were found in ΔE, and all coordinates (p<.05) between control and stained groups, with major changes in the stained group for both treatments. The control group showed greater alteration in Δb, being higher (p<.05) for bleached teeth, decreasing in yellowness. For stained teeth, Δa showed the greatest change, decreasing in redness, being higher (p<.05) for bleached teeth. Both treatments were effective for removing stains, and tooth whitening proved to be a more efficient method for removing stains from teeth that had not been subjected to the previous staining.
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