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Restorative procedures associated with bioglasses have shown to be a strategy to satisfy the contemporary concept of minimally invasive dentistry. Thus, the aim of this study was to evaluate bond strength to dentin treated by two different methods of biosilicate microparticle application. Dentin surfaces from 30 sound human molars were exposed and randomly assigned into three groups (n = 10) according to the surface treatment: (1) blasting with biosilicate microparticles (distance = 1 cm/pressure = 5 bar/time = 1 min); (2) 10% biosilicate microparticles paste; and (3) control (no treatment). After, dentin surfaces were restored with self-etch adhesive (Adper Easy Bond) and nanofilled composite (Filtek Z350). Specimens were sectioned perpendicularly to the adhesive interface to obtain sticks (cross-section area = 1 mm2), which were submitted to microtensile test (0.5 mm/min; 50 kgf). Data were analyzed by ANOVA and Tukey’s test (α = 5%). Dentin/adhesive interfaces were morphologically analyzed by scanning electron microscopy (SEM). Data analysis showed that biosilicate-treated groups reached similar results (p > 0.05) and both of them demonstrated higher values (p < 0.05) than control group. SEM micrographs revealed hybridization with clear resin tags and no separation between resin-dentin adhesive interfaces. Within the limitations of this study, surface treatment with biosilicate positively influenced the adhesion to dentin and does not alter the morphology of the adhesive interface.

The aim of this study was to evaluate the effect of cavity preparation with Er:YAG laser on dentin adjacent to restorations submitted to cariogenic challenge in situ, by subsuperficial microhardness analysis. Bovine incisors were sectioned, flattened, and polished, resulting in 40 dentin slabs. The slabs were randomly assigned to four groups ( n  = 10), according to the cavity preparation method: I—high-speed handpiece (control); II—Er:YAG laser (160 mJ; 3 Hz); III—Er:YAG laser (260 mJ; 3 Hz); IV—Er:YAG laser (300 mJ; 3Hz). Cavities were restored with composite resin, and the specimens were fixed in intra-oral appliances, which were worn by 10 volunteers for 14 days for simulating cariogenic challenge in situ. During the experimental period, 20% sucrose solution was dripped over each specimen 6 times a day. Samples were removed, sectioned, and examined for subsuperficial Knoop microhardness at 100, 200, and 300 μm from the restoration and at 30 μm from dentin surface. Split-plot analysis of variance showed no significant difference among the cavity preparation techniques ( p  = 0.1129), among distances ( p  = 0.9030), as well as no difference in the interaction between the main factors ( p  = 0.7338). It was concluded that the cavity preparation with Er:YAG laser did not influence on dentin microhardness submitted to cariogenic challenge in situ.

This study evaluated the microhardness of superficial and deep dentin irradiated with different erbium:yttrium–aluminum–garnet (Er:YAG) laser energies. Seventy-two molars were bisected and randomly assigned to two groups (superficial dentin or deep dentin) and into six subgroups (160 mJ, 200 mJ, 260 mJ, 300 mJ, 360 mJ, and control). After irradiation, the cavities were longitudinally bisected. Microhardness was measured at six points (20 µm, 40 µm, 60 µm, 80 µm, 100 µm, and 200 µm) under the cavity floor. Data were submitted to analysis of variance (ANOVA) and Fisher’s tests (α = 0.05). Superficial dentin presented higher microhardness than deep dentin; energy of 160 mJ resulted in the highest microhardness and 360 mJ the lowest one. Values at all points were different, exhibiting increasing microhardness throughout; superficial dentin microhardness was the highest at 20 µm with 160 mJ energy; for deep dentin, microhardness after irradiation at 160 mJ and 200 mJ was similar to that of the control. The lowest energy increased superficial dentin microhardness at the closest extent under the cavity; deep dentin microhardness was not altered by energies of 160 mJ and 200 mJ.

The purpose of this study was to analyze, by Scanning Electron Microscopy (SEM), the surface topography and the morphology of the adhesive interfaces of enamel and dentin after different treatments. The enamel-dentin discs were randomly assigned into three groups according to the surface treatment: I-37% phosphoric acid; II-air-abrasion; III-air-abrasion followed by 37% phosphoric acid. After surface treatment, discs were divided in two: one hemi-disc was separated for surface analysis; the other hemi-disc received the Single Bond/Filtek Z-250 restorative system. The restored sections were bisected perpendicularly to the surface and prepared for interface analysis. Results disclosed that when the surface treatment was performed by air-abrasion, irregularities were observed at the enamel surface; microcracks and occluded tubules at dentin surface and lack of hybrid layer at adhesive/dentin interface. The air-abrasion treatment followed by acid etching provided an enamel etching pattern similar to the acid etching; microfissures and open tubules at dentin surface, and formation of hybrid layer at adhesive-dentin interface. It may be concluded that the treatment with air-abrasion followed by acid etching is an effective procedure to obtain an adequate surface for resin adhesion.