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.

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ObjectivesThis study evaluated the effects of a bleaching agent on the composition, mechanical properties, and surface topography of 6 conventional glass-ionomer cements (GICs) and one resin-modified GIC.Materials and MethodsFor 3 days, the specimens were subjected to three 20-minute applications of a 37% H2O2-based bleaching agent and evaluated for water uptake (WTK), weight loss (WL), compressive strength (CS), and Knoop hardness number (KHN). Changes in surface topography and chemical element distribution were also analyzed by energy-dispersive X-ray spectroscopy and scanning electron microscopy. For statistical evaluation, the Kruskal-Wallis and Wilcoxon paired tests (α = 0.05) were used to evaluate WTK and WL. CS specimens were subjected to 2-way analysis of variance (ANOVA) and the Tukey post hoc test (α = 0.05), and KH was evaluated by one-way ANOVA, the Holm-Sidak post hoc test (α = 0.05), and the t-test for independent samples (α = 0.05).ResultsThe bleaching agent increased the WTK of Maxxion R, but did not affect the WL of any GICs. It had various effects on the CS, KHN, surface topography, and the chemical element distribution of the GICs.ConclusionsThe bleaching agent with 37% H2O2 affected the mechanical and surface properties of GICs. The extent of the changes seemed to be dependent on exposure time and cement composition.

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The purpose of this study was to describe the synthesis, characterization, and functionalization of b-NaYF 4 :30%Yb/0.5%Tm upconverting nanocrystals for use as nanofillers in a dental adhesive and microscopically evaluate the interface between the particles and a commercial adhesive. The upconverting nanoparticles were synthesized and purified by thermal decomposition, and their chemical composition determined by energy dispersive X-Ray spectroscopy. The crystalline structure was characterized using X-Ray diffraction and morphology and size were observed with scanning and transmission electron microscopy. Upconverting emission was evaluated by spectrophotometry irradiating the particles with a 975 nm diode laser. Particles were functionalized with polyacrylic acid and the success was confirmed by measurement of Zeta Potential and transmission electron microscopy. The results of X-ray diffraction found a pure hexagonal phase crystalline pattern. Scanning electron microscopy showed uniform dispersion of hexagonal-shaped particles of approximately 150 nm. Upconversion emission was observed in 344 nm, 361 nm, 450 nm, 474nm, 646 nm, 803 nm. Functionalization success was confirmed by formation of a stable aqueous colloid with a Zeta potential of -29.5mV and the absence of voids in the particle-adhesive interface on the transmission electron microscopy images. The reported synthesis and functionalization process produced upconverting nanoparticles emitting photons within the blue spectral region (450 nm and 474 nm).