SUMMARYNanohybrid resin composites present conventional particles to be mixed with nanomeric fillers and, therefore, it is unknown whether they may perform similarly to nanofilled or microhybrid resins. The current study investigated the properties of nanohybrid resins (TPH 3 , Grandio, Premise, Concept Advanced) in comparison with a nanofilled (Supreme XT) and a microhybrid (Z250) composite. The inorganic fillers were characterized by SEM/EDS analysis. Diametral tensile strength (DTS), surface roughness before and after toothbrush abrasion, Knoop Hardness (KHN), water sorption and solubility were evaluated. The data were separately analyzed by ANOVA and the Student-Newman-Keuls' tests (p<0.05). The results of all analyses were material-dependent. Noticeable differences in filler size and shape were detected among the materials. Supreme XT generally showed higher DTS and KHN compared to all the nanohybrids and also showed lower surface roughness before and after toothbrush abrasion compared to most of the materials tested. Similar results were generally detected for the nanohybrids compared with the microhybrid material. In conclusion, the nanohybrid resins generally presented inferior properties compared with the nanofilled composite and either similar or slightly better properties com-

EDAB proved to be more reactive than DMAEMA, being less influenced by DPI. Resins containing a 1:2 CQ/amine ratio had better properties than those with 1:1.

<p><strong>Objective:</strong> The aim of this study was to evaluate the effect of mouthrinses on the surface roughness of the nanofilled restorative composite. <strong>Material and Methods</strong>: Twenty discs (4 mm in diameter and 1 mm in height) of the composite Filtek Z350 were made and roughness (µm) was measured using perfilometer with a 0.5 μm diamond needle tip measuring and accuracy of 0.01 μm. The discs were randomly divided into four groups (n=5): Control (distilled water), G1-Plax, G2-Plax Whitening e G3-Listerine and individually storage in eppendorfs with distilled water at 37°C. The specimens were maintained in distilled water during 30 d and immersed in mouthrinses every 12 h for 1 min. after the 30 d the specimens was cleaned in distilled water, storage in oven at 37°C during 24 h and the surface roughness test was repeated with the same parameters previously described. The data were submitted to Two-way ANOVA and the t-studant test for paired specimens. <strong>Results</strong>: No significant differences among groups were detected R1: Control (0.12±0.04); G1 (0.13±0.05); G2 (0.11±0.03); G3 (0.11±0.02); and R2: Control (0.16±0.04); G1 (0.15±0.02); G2 (0.13±0.01) e G3 (0.15±0.02).<strong> Conclusions</strong>: In this study the mouthrinses solutions did not promote significant changes on the surface roughness of Filtek Z350 after 30 d.</p><p><strong>Keywords</strong>: Composites; Polymer; Dental materials</p>

The objective of this study was to evaluate the effects of diode laser and a desensitizing dentifrice on dentin permeability. Fifty-two root dentin fragments were obtained (5 × 5mm) and treated with 24% EDTA gel. The samples were divided into 4 groups (n = 13): G1, control (no treatment); G2, diode laser (λ = 908 nm, 1.5 W, continuous mode, 20s); G3, application of abrasive dentifrice for 1 minute (Elmex Sensitive Professional (International Gaba); and G4, application of abrasive dentifrice for 1 minute followed by irradiation with diode laser. Ten samples per group were immersed in 2% methylene blue solution for 4h. The specimens were washed, longitudinally sectioned, observed under optical microscopy, photographed and assessed based on the degree of dye leakage. The remaining samples were observed under scanning electron microscopy (SEM). The leakage data were subjected to ANOVA test, followed by Tukey's t-test (α = 5%). Groups 2, 3 and 4 showed less dye penetration than the control group (p < 0.05), but were similar among each other. SEM images showed that dentinal tubules were open in G1, and fused and occluded in G2. Group 3 showed dentinal tubules that were occluded by the metal ions from the toothpaste. G4 presented similar characteristics to G3, and the presence of fused dentin. The diode laser and the dentifrice were effective in reducing dentinal permeability, and the combination of the two treatments did not show better results than either one used alone.

No abstract