©Operative Dentistry, 2007, 32-4, 380-387 SUMMARYThis study compared the effects of moisture and rubbing action on the immediate and one-year microtensile bond strength (BS) of an ethanol/water-based adhesive system (Single Bond [SB]) and an acetone-based system (One Step [OS]) to dentin. A flat superficial dentin surface on 60 human molars was exposed by wet abrasion. Two coats of the adhesives were applied on either a dry (D) or rewetted surface (W) with no (NRA), slight (SRA) or vigorous rubbing action (VRA). After light curing (600mW/cm 2 /10 seconds), composite buildups were constructed incrementally and the specimens were stored in water (37°C/24 hours). They were longitudinally sectioned in the "x" and "y" directions to obtain bonded sticks (0.8 mm 2 ) to be tested in tension at 0.5 mm/minute. The sticks from each tooth were then divided, stored in water at 37°C and tested immediately and after 12 months (12M) at 0.5 mm/minute. The bond strength values of sticks from the same hemitooth were averaged for statistical purposes. The prematurely debonded specimens were included in the hemi-tooth mean. The data from each adhesive was analyzed by three-way ANOVA and Tukey's multiple comparison tests (α=0.05). In the dry groups, high bond strength values were obtained under VRA. When the Clinical RelevanceAs long as adhesives are vigorously rubbed onto dentin surfaces, high immediate and long-term bond strengths can be obtained to either air-dried or wet demineralized dentin. INTRODUCTIONAs reported by Spencer and Wang, 1 the two primary critical factors for achieving an adequate resin-dentin bonding are wetting of the dentin by components of the adhesive and micromechanical interlocking via resin penetration and the entanglement of exposed collagen fibrils in demineralized dentin.

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The effect of surface preparation was adhesive-dependent. Improvements in resin-enamel bond strength after enamel preparation were observed only for AdheSE and Optibond Solo plus SelfEtch Primer. Among the self-etch systems, mild, self-etch Clearfil SE Bond showed the highest bond strength values. No degradation of resin-enamel bonds was observed after 12 months of water storage, regardless of the adhesive tested. SUMMARY

Objectives:To assess the bond strength and the morphology of enamel after application of self-etching adhesive systems with different acidities. The tested hypothesis was that the performance of the self-etching adhesive systems does not vary for the studied parameters.Material and methods:Composite resin (Filtek Z250) buildups were bonded to untreated (prophylaxis) and treated (burcut or SiC-paper) enamel surfaces of third molars after application of four self-etching and two etch-and-rinse adhesive systems (n=6/condition): Clearfil SE Bond (CSE); OptiBond Solo Plus Self-Etch (OP); AdheSe (AD); Tyrian Self Priming Etching (TY), Adper Scotchbond Multi-Purpose Plus (SBMP) and Adper Single Bond (SB). After storage in water (24 h/37°C), the bonded specimens were sectioned into sticks with 0.8 mm2 cross-sectional area and the microtensile bond strength was tested at a crosshead speed of 0.5 mm/min. The mean bond strength values (MPa) were subjected to two-way ANOVA and Tukey's test (α=0.05). The etching patterns of the adhesive systems were also observed with a scanning electron microscope.Results:The main factor adhesive system was statistically significant (p<0.05). The mean bond strength values (MPa) and standard deviations were: CSE (20.5±3.5), OP (11.3±2.3), AD (11.2±2.8), TY (11.1±3.0), SBMP (21.9±4.0) and SB (24.9±3.0). Different etching patterns were observed for the self-etching primers depending on the enamel treatment and the pH of the adhesive system.Conclusion:Although there is a tendency towards using adhesive systems with simplified application procedures, this may compromise the bonding performance of some systems to enamel, even when the prismless enamel is removed.

SUMMARYObjective: To examine the morphological, early and long-term microtensile bond strengths (µTBS) of one-step self-etch systems to unground and ground enamel. Materials and Methods:Resin composite (Filtek Z250) buildups were bonded to the buccal and lingual enamel surfaces (unground, bur-cut or SiC-roughened enamel) of third molars after adhesive application using the following adhesives: Clearfil S 3 Bond (CS3); Adper Prompt L-Pop (ADP); iBond (iB) and, as the control, Clearfil SE Bond (CSE). Six tooth halves were assigned for each condition. After storage in water (24 hours/37°C), the bonded specimens were sectioned into beams (0.8 mm 2 ) and subjected to µTBS (0.5 mm/min) either immediately (IM) or after six (6M) or 12 months (12M) of water storage. The data were analyzed by three-way repeated measures ANOVA and Tukey's test (α α=0.05). A Reis • SKThe improvement of resin-enamel bond strengths after using Si-C paper and diamond burs for enamel preparation is material dependent. No degradation of enamel bond strength could be observed for any one-step self-etch adhesive system after 12 months of water storage. Surface conditioning was observed under scanning electron microscopy (SEM).Results: The µTBS in the Si-C paper and diamond bur groups were similar and higher than the unground group. No significant difference was observed among the different storage periods, except for CS3, which showed an increase in the µTBS after 12M. The etching pattern was more retentive on ground enamel. Conclusions: One-step self-etch adhesives showed higher bond strengths on ground enamel and no reductions in resin-enamel bonds were observed after 12M of water storage.