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Statement of Problem: According to manufacturers, bonding with self-adhesive resin cements can be achieved without any pretreatment steps such as etching, priming, or bonding. However, the benefit of saving time with these simplified luting systems may be realized at the expense of compromising the bonding capacity., Purpose: The purpose of this study was to assess whether different dentin conditioning protocols influence the bond performance of self-adhesive resin cements to dentin., Material and Methods: Flat dentin surfaces from 48 human molars were divided into 4 groups (n=12): 1) control, no conditioning; 2) H(3)PO(4), etching with 37% H(3)PO(4) for 15 seconds; 3) SEBond, bonding with self-etching primer adhesive (Clearfil SE Bond); and 4) EDTA, etching with 0.1M EDTA for 60 seconds. The specimens from each dentin pre-treatment were bonded using the self-adhesive cements RelyX Unicem, Maxcem or Multilink Sprint (n=4). The resin-cement-dentin specimens were stored in water at 37°C for 7 days, and serially sectioned to produce beam specimens of 1.0 mm(2) cross-sectional area. Microtensile bond strength (μTBS) testing was performed at 1.0 mm/min. Data (MPa) were analyzed by 2-way ANOVA and Tukey multiple comparisons test (α=.05). Fractured specimens were examined with a stereomicroscope (x40) and classified as adhesive, mixed, or cohesive. Additional bonded interfaces were evaluated under a scanning electron microscope (SEM)., Results: Cement-dentin μTBS was affected by the dentin conditioning approach (P<.001). RelyX Unicem attained statistically similar bond strengths to all pre-treated dentin surfaces. H(3)PO(4)-etching prior to the application of Maxcem resulted in bond strength values that were significantly higher than the other groups. The lowest μTBS were attained when luting Multilink Sprint per manufacturers' recommendations, while H(3)PO(4)-etching produced the highest values followed by Clearfil SE bonding and EDTA. SEM observations disclosed an enhanced potential of the self-adhesive cements to form a hybrid layer when applied following manufacturer's instructions., Conclusions: When evaluated self-adhesive resin cements are used, selectively etching dentin with H(3)PO(4) prior to luting results in the most effective bonding., (Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Purpose: To evaluate the laboratory resistance to degradation and the use of different bonding treatments on resin-dentin bonds formed with three self-etching adhesive systems., Methods: Flat, mid-coronal dentin surfaces from extracted human molars were bonded according to manufacturer's directions and submitted to two challenging regimens: (A) chemical degradation with 10% NaOC1 immersion for 5 hours; and (B) fatigue loading at 90 N using 50,000 cycles at 3.0 Hz. Additional dentin surfaces were bonded following four different bonding application protocols: (1) according to manufacturer's directions; (2) acid-etched with 36% phosphoric acid (H3PO4) for 15 seconds; (3) 10% sodium hypochlorite (NaOClaq) treated for 2 minutes, after H3PO4-etching; and (4) doubling the application time of the adhesives. Two one-step self-etch adhesives (an acetone-based: Futurabond/FUT and an ethanol-based: Futurabond NR/FNR) and a two-step self-etch primer system (Clearfil SE Bond/CSE) were examined. Specimens were sectioned into beams and tested for microtensile bond strength (microTBS). Selected debonded specimens were observed under scanning electron microscopy (SEM). Data (MPa) were analyzed by ANOVA and multiple comparisons tests (alpha= 0.05)., Results: microTBS significantly decreased after chemical and mechanical challenges (P< 0.05). CSE showed higher microTBS than the other adhesive systems, regardless the bonding protocol. FUT attained the highest microTBS after doubling the application time. H3PO4 and H3PO4 + NaOCl pretreatments significantly decreased bonding efficacy of the adhesives.

Objective: To evaluate the resistance to degradation of resin-dentin bonds formed with a one-step acetone-containing and HEMA-free adhesive., Methods: Flat, mid-coronal dentin surfaces were bonded with G Bond under dry and wet conditions. The bonded teeth were subjected to fatigue loading (90 or 250 N) using 5000 or 50000 cycles (at 3.0 Hz) and to chemical degradation (10% NaOCl immersion for 5 h). Specimens were sectioned into beams and tested for microtensile bond strength. Fractographic analysis was performed by scanning electron microscopy (SEM). Additional specimens were processed for morphological examination of the interfaces., Results: Bond strength significantly decreased after the chemical challenge (p<0.05), but not after load cycling. Dentinal moisture did not affect bond strength. Most of the recorded failures were adhesive and located at the top of the hybrid layer. A poorly infiltrated hybrid layer with bubbles entrapped within the adhesive was observed in all groups., Conclusions: A discrepancy between water/solvent evaporation rate and convective and evaporative water fluxes from the underlying dentin may be responsible of the droplet formation within the adhesive layer, thus reducing bond strength. A "stress relieving" effect may occur during loading. A loss of bonding effectiveness is expected overtime, mainly due to chemical degradation of the hybrid layer.