Resin cement diffusion into dentin may differ as a function of the pre-treatment regimen. Since self-adhesive cements do not require substrate pre-treatment for luting, penetration of and interaction with the underlying dentin are questioned. We hypothesized that differences in the resin cement diffusion into dentin may exist among current commercial adhesive cements. Composite cylinders were luted on mid-coronal dentinal surfaces by an etch-and-rinse cement (Calibra), a self-etching system (Panavia F 2.0), and 4 self-adhesive cements (Multilink Sprint, Rely X Unicem, G-Cem, Bis-Cem). Dentin/cement interfacial characteristics were analyzed by a staining technique (Masson's trichrome) and by scanning electron microscopy. Conventional acid etching resulted in partially infiltrated adhesive interfaces differing from those achieved with the application of self-etching primer. No hybrid layer and/or resin tag formation was detectable at the interfaces bonded with self-adhesive cements. Limited decalcification/infiltration was observed for self-adhesive cements into the underlying dentin. Self-adhesive cements were not able to demineralize/dissolve the smear layer completely.

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The aim of this study was to investigate the adhesion of fiber posts cemented with luting agents that utilize three currently available adhesive approaches: etch-and-rinse, self-etch, and self-adhesive. Forty-two intact single-rooted human premolars were used in the study. Teeth were divided into six groups. In each group, a different resin cement with its adhesive system (if needed) and a fiber post were used. The groups were classified, according to the adhesive approach, into the following three categories. (i) Etch-and-rinse groups: Calibra resin cement/XPBond adhesive + self-curing activator (SCA)/RadiX Fiber Post (Dentsply Caulk), FluoroCore 2 core build-up material/XPBond + SCA/RadiX Fiber Post (Dentsply Caulk), and MultiCore Flow luting and core build-up material/Excite DSC adhesive/FRC Postec Plus fiber post (Ivoclar Vivadent). (ii) Self-etch group: Panavia F 2.0/ED primer (Kuraray)/RadiX Fiber Post (Dentsply Caulk). (iii) Self-adhesive groups: experimental self-adhesive cement/RadiX Fiber Post (Dentsply Caulk), and RelyX Unicem/RelyX Fiber Post (3M ESPE). The adhesion between the post and the root canal walls was assessed using the 'thin-slice' push-out test. In the test arrangement used, the self-etching approach may offer less favourable adhesion to root canal dentin in comparison with etch-and-rinse and self-adhesive approaches.

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Mazzitelli C, Monticelli F, Toledano M, Ferrari M, Osorio R. Dentin treatment effects on the bonding performance of self‐adhesive resin cements. Eur J Oral Sci 2010; 118: 80–86. © 2010 The Authors. Journal compilation© 2010 Eur J Oral Sci The effects of dentin surface treatments on the microtensile bond strengths and on the interfacial characteristics of self‐adhesive resin cements were investigated. Flat dentin surfaces were obtained from human molars and were treated as follows: (i) no treatment of dentin; (ii) 0.1 M EDTA scrubbed for 60 s; or (iii) 10% polyacrylic acid applied for 30 s. Three self‐adhesive cements were used to lute composite overlays on deep‐coronal dentin surfaces in the presence of simulated pulpal pressure (15 cm of H2O). Bonded specimens were cut into beams 1 mm thick and stressed in tension until failure. Fractured sticks were examined under a scanning electron microscope. Additional specimens were stained with Masson’s trichrome and observed under light microscopy for interfacial evaluations. The bond strength to dentin of the hydrophobic and solvent‐free cement (RelyX Unicem) was unaffected by the tested dentin treatments. The bond strength of the 2‐hydroxyethyl methacrylate (HEMA)‐based cement (Bis‐Cem) decreased after treatment of dentin with EDTA and/or polyacrylic acid. The hydrophilic and water‐containing cement (G‐Cem) attained a higher bond strength when luted on polyacrylic acid‐conditioned dentin. In conclusion, smear layer removal, opening of dentinal tubules, and the water content of dentin differently influence the bond strengths and the interfacial characteristics of self‐adhesive cement–dentin interfaces.

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SUMMARYThis study investigated the composite-to-composite microtensile bond strength and interfacial quality after using different combinations of intermediate agents and pre-curing temperatures of repairing resin. Forty-five composite discs (8x4mm) of Gradia Direct Anterior (GC Corp), stored in a saline solution at 37°C for one month, were sandblasted (50 µm aluminum oxide), cleaned (35% phosphoric acid) and randomly divided into three groups (n=15) according to the intermediate agent applied: 1) no treatment; 2) unfilled resin (Scotchbond MultiPurpose Adhesive, 3M ESPE); 3) flowable composite (Gradia LoFlo, GC Corp). Each disc was incrementally repaired (8x8 mm) with the same resin as the substrate. For each group, three subgroups (n=5) were created, depending on the pre-curing temperature of the repairing resin-4°C, 23°C or 37°C. Two bonded specimens per group were prepared to evaluate the compositeto-composite interfacial quality via scanning electron microscope. Microtensile bond strength measurements were performed withThe combination of a flowable composite as an intermediate agent and a repairing material at a temperature of 23°C or 37°C prior to light curing may be recommended as a simple, suitable procedure to provide higher bond strengths and uniform composite-to-composite interfacial adaptation.