This study investigated the effect of light-curing of Clearfil DC Bond (DC Bond) on the micro-tensile bond strength of Clearfil Esthetic Cement to dentin. Extracted human teeth were used in this study. The coronal dentin surfaces were prepared, and treated with DC Bond with or without light-curing, or ED primer II according to the manufacturer's instruction and luted composite block using Clearfil Esthetic Cement. The bond strengths were measured with the micro-tensile bond test. The bond strengths were statistically compared with ANOVA and Duncan's new multiple range tests. The debonded specimens and resin-dentin interfaces were also examined by SEM. There were no significant differences in bond strength among all the groups. In the SEM observations, no morphological differences were found among all the groups. For all fractured surfaces in the debonded DC Bond with light-curing group, cohesive failure in resin was observed. Adhesive fracture was predominantly observed in the debonded DC Bond without light-curing group. The cohesive failure in resin was predominantly observed in the debonded ED primer group.
In conclusion, although the type of fractured surface for the DC Bond without light-curing group differed from that for the DC Bond with light-curing group, there was no significant difference in the dentin bond strength of Clearfil Esthetic Cement between the two groups.

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An adhesive resin cement was experimentally designed by Dentsply-Sankin Co. The purpose of this study was to observe the cored structure of the set cement, and the interfacial ultrastructure between the cement in combination with the experimental bonding agent for resin core restoration and enamel/dentin under SEM by means of the Ar-ion beam etching technique. A human extracted molar was longitudinally cut, and the surfaces of enamel and dentin were finished with # 1, 000 SiC paper. The surfaces were treated with the experimental bonding agent and light-cured according to the manufacturer's instruction, and then the experimental resin cement was placed on the surfaces and light-cured. According to previous studies, the specimen was cut in half and embedded in epoxy resin. After being polished with SiC paper and diamond paste, the specimen was subjected to Ar-ion beam etching for35seconds, and then observed under SEM. According to the SEM observation, the experimental resin cement was classified into the category of heavily-filled type containing spherical filler particles. The experimental resin cement in combination with the experimental bonding agent showed a tight interfacial junction to enamel/dentin. At the superficial dentin layer, a very thin hybrid layer was observed. This experimental resin cement showed satisfactory adhesion to the tooth tissue, and this system is thought to be promising for clinical use.

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This study investigated the bond strengths of one-or two-step self-etching adhesive systems to human sound, demineralized and remineralized dentin. Remineralized dentin was created by remineralization for1or4weeks after demineralization. The dentin surfaces were treated with Clearfil SE Bond or Clearfil Tri-S Bond and the microtensile bond strengths were measured. There were no significant differences in the bond strength of Clearfil SE Bond among the three groups (demineralized, 1-week and4-week remineralized dentin groups) except for the sound dentin group. On the other hand, the bond strength of Clearfil Tri-S Bond to1-week remineralized dentin was significantly higher than those to demineralized dentin and4-week remineralized dentin. In comparing the two adhesive systems, Clearfil SE Bond produced higher bond strengths to all dentin surfaces than Clearfil Tri-S Bond. In conclusion, it is suggested that the difference of the adhesive system affected the bond strength to demineralized and remineralized dentin.

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Giomer, which was developed by Shofu Company, contains S-PRG filler to obtain fluoride releasing characteristics and good mechanical properties that can be applicable to posterior cavities. Improved Giomer, Beautifil II and a bonding system, Fluorobond II, have been introduced in the market recently and we observed the adhesive interface using SEM. We also used the new restorative system in daily treatment to evaluate handling characteristics and clinical performance. The Fluorobond II adhesive system provided good adhesion to the enamel surface by forming a 50μm thick bonding layer. It also revealed tight sealing between dentin substrate and no gap formation was observed. Dentinal plugs and resin-tag like structure were observed in the dentinal tubules. The hybrid layer was not clear and the so-called nano-interaction zone may have been present in the superficial surface of the dentin. These materials were used in the clinical treatment and showed good handling characteristics, polished surface and excellent color match.

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The aim of this study was to evaluate the bond strength and durability of three bonding systems joined to a prefabricated porcelain material etched with5% hydrofluoric acid, and to analyze the porcelain surface before and after etching. As a result of etching with hydrofluoric acid, the amount of silicon oxide on the porcelain surface increased, while the amount of aluminum oxide decreased. The greatest bond strength was exhibited by the Monobond S and Variolink II combination before and after thermocycling. Of the three bonding systems (Clapearl Bonding Agent and Clapearl DC, Porcelain Liner M and Super-Bond C&B, Monobond S and Variolink II), the Monobond S and Variolink II system was recommended for bonding with the porcelain. Bond strength and durability of the prefabricated porcelain are thought to be related to the surface characteristics and composition before bonding.

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