High-concentration carbamide peroxide containing home bleaching may cause a varying influence on the microhardness of esthetic restorative materials. SUMMARYThis study evaluated the effect of a highconcentration carbamide peroxide-containing home bleaching system (Opalescence PF) and a hydrogen peroxide-containing over-the-counter bleaching system (Treswhite Supreme) on the microhardness of two nanocomposites (Filtek Supreme XT and Premise) and leucitereinforced glass ceramic (Empress Esthetic), glass ceramic (Empress 2 layering), and feldspathic porcelain (Matchmaker MC). A total of 100 specimens, 20 of each kind of the restorative materials, 2 mm in thickness and 10 mm in diameter, were fabricated. Then the specimens were polished with SiC paper and 1 lm alumina polishing paste. After polishing, porcelain specimens were glazed in accordance with the manufacturer's instructions. Each type of restorative material was then randomly divided into two groups (n¼10), and the specimens were treated with either Opalescence PF or Treswhite Supreme. The microhardness of the specimens before bleaching (baseline) and after bleaching was determined using a digital microhardness tester. Data were analyzed using the Mann-Whitney U-test and the Wilcoxon test.Opalescence PF significantly influenced the hardness of all the restorative materials. Statistically significant decreases with respect to before bleaching were found for Premise (p¼0.005), Empress Esthetic (p¼0.003), Empress 2 layering (p¼0.005), and Matchmaker-MC (p¼0.003), whereas a statistically significant

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The purpose of this study was to investigate surface roughness (Ra) and morphology of supra-nanofilled [Estelite Omega (EO), Estelite ∑ Quick (EQ)], micro-hybrid [Esthet.X HD (EHD), G-aenial (GAE)] and nano-hybrid [Clearfil Majesty Posterior (CMP), Charisma Diamond (CD), Beautifil II (BII)] composites polished with two-step polishing systems [Enhance/PoGo (EP); Venus Supra (VS)]. Composite discs, 30 of each type, were prepared. Each composite group was divided into three subgroups: Mylar (control), EP and VS. Ra was evaluated with profilometer. In each composite group, the control had the lowest Ra. With both polishing systems, EO and EQ had significantly the lowest Ra, whereas CMP and BII had the highest. Except for GAE, CD and BII, the differences in Ra between EP and VS in each composite group were significant, showing smoother surfaces for EP. Supra-nanofilled composites created smoother surfaces than nano-hybrids, and their performance was similar or slightly better than that of micro-hybrids.

The two-fold aims of this study were: (1) to evaluate the microtensile bond strengths of different adhesive systems to sclerotic and sound palatal dentin; and (2) to observe the respective resin-dentin interfaces. Thirty extracted human incisor teeth were divided into two groups. Group I comprised sclerotic defects in the palatal zone. Group II comprised sound palatal dentin surfaces as control. Each group (n=15) was divided into three subgroups according to dentin adhesive systems: self-etch (Clearfil SE Bond), total-etch (Scotchbond Multi-Purpose Plus), and glass ionomer (Reactmer Bond) adhesive systems. The specimens were subjected to tensile forces. Obtained data were analyzed by two-way ANOVA and post hoc Duncan's test. Fracture sites and resin-dentin interfaces were observed using a light microscope and SEM. With sound dentin, Clearfil SE Bond showed a significantly higher bond strength than the other adhesives (p<0.05). With sclerotic dentin, although there were no significant differences in bond strength among the adhesives groups (p>0.05), the bond strength values of Clearfil SE Bond and Scotchbond Multi-Purpose Plus were significantly decreased. On resin-dentin interface observation, different images were presented by different bonding systems.

Selective acid-etching of the enamel margins enhanced the performance of the two-step self-etch adhesive in terms of marginal discoloration and marginal adaptation at the enamel side.