The objective of this study was to evaluate, using methylene blue (MB), the effects of various light sources on the bleaching action of hydrogen peroxide (H2O2) with two titanium dioxide (TiO2) photocatalysts -an ultraviolet light-activated TiO2 photocatalyst (UV TiO2) versus a visible light-activated TiO2 photocatalyst (VL-TiO2). Five experimental solutions (VL-TiO2+H2O2, UV-TiO2+H2O2, H2O2, VL-TiO2, UV-TiO2) were prepared by mixing varying concentrations of H2O2 and/or TiO2 photocatalyst with MB solution. For H2O2-containing solutions (VL-TiO2+H2O2, UV-TiO2+H2O2, and H2O2), the concentration of H2O2 was adjusted to 3.5%. For the four different light sources, low-and high-intensity halogen lamps and blue LED LCUs were used. All the experimental solutions were irradiated by each of the light sources for 7 minutes, and the absorbance at 660 nm was measured every 30 seconds to determine the concentration of MB as an indicator of the bleaching effect. On the interaction between the effects of light source and bleaching treatment, the high-intensity halogen with VL-TiO2+H2O2 caused the most significant reduction in MB concentration. On the effect of light sources, the halogen lamps resulted in a greater bleaching effect than the blue LED LCUs.

The purpose of this in vitro study was to evaluate marginal integrity and wall adaptation in 1-and 2-mm-deep cavities restored with a high filler-loaded flowable composite in comparison to a flowable composite with lower filler content and a conventional hybrid composite. 1-mm-deep dentin and 2-mm-deep enamel-dentin Class I cavities were prepared and restored with a self-etch adhesive and with one of the composites. Samples were crosscut and evaluated for marginal integrity and gap formation using a digital microscope. Selected samples were also observed using a scanning electron microscope. For 1-mm-deep cavities, no differences in marginal integrity and wall adaptation were observed among the three composites. For 2-mm-deep cavities, those restored with the bulk technique and with the higher filler-loaded flowable composite demonstrated a similar outcome as that of the conventional hybrid composite. On the effect of restorative techniques, cohesive enamel defects were observed in bulk-filled 2-mm-deep cavities. However, when the incremental technique was used in conjunction with the higher filler-loaded flowable composite and the conventional hybrid composite for 2-mm-deep cavities, superior results were obtained.

The purpose of this investigation was to measure and compare both the surface roughness and gloss of flowable composites polished with standardized silicone carbide (SiC) papers. Four flowable and two conventional composites were used in this study. Polymerized specimens were subjected to a polishing procedure comprising 12 sequential steps from coarser to finer grits of SiC paper. At the initial polishing stage, flowable composites were more sensitive to the size of the polishing particles and thus yielded surfaces rougher than the conventional composites. Surface roughness became stable when polishing particles less than 13 μm size were used. However, although surface roughness was reduced, an esthetic gloss quality was not achieved on the resultant polished surface. On the influence of filler shape, composites with spherical fillers seemed to have the upper-hand advantage of attaining a high gloss by polishing. On the influence of polishing particle size, it was suggested that polishing should be completed with polishing particles less than 12 μm size so as to achieve clinically satisfactory surface roughness and gloss.

The purpose of this study was to evaluate the dentin bonding durability of three HEMA-containing one-step self-etch adhesives after one-year water storage and to measure the amounts of their water sorption/solubility. OptiBond All-In-One (OP), Bond Force (BF) and Clearfil S 3 Bond (S 3 ) were applied to the dentin surfaces according to manufacturers' instructions. Bond strengths to dentin were determined using µTBS test after water storage for 24 hours, six months, and one year. In addition, water sorption and solubility of the polymerized adhesives were measured. The µTBS of S 3 and OP significantly decreased after one year. On the other hand, for BF there were no significant differences in µTBS between all storage periods. There were significant differences in water sorption and solubility among the adhesives (BF>S 3 >OP). The initial amounts of water sorption and solubility of the three adhesives did not affect their bonding durability to dentin.

This study was designed to evaluate effects of light-irradiated intensities directly and indirectly through resin composites to one-and two-step self-etch adhesives on dentin bonding. One-step (Clearfil S 3 Bond; TS, Bond Force; BF) or two-step (Clearfil SE Bond; SE) self-etch adhesives was applied to dentin surface. The adhesive agent was light-cured with light-intensity of 350 or 600 mW/cm 2 , and then resin composite with different colors (translucent or opaque shade) was filled and light-cured with the same light-intensity as the bonding procedure. After 24 h water storage, bond strengths to dentin were determined using µTBS test. For the 600 and 350 mW/ cm 2 groups, translucent shade resin obtained higher µTBS than opaque shade resin. Using SE and BF, the 350 mW/cm 2 group in translucent shade resin was higher µTBS than the 600 mW/cm 2 group in opaque shade resin, while TS showed no different µTBS between them.