2013 Volume 56 Issue 4 Pages 360-369
Purpose: The purpose of this study was to evaluate the mechanical properties and the bonding properties of resin cements on the assumption that a resin-retained bridge was bonded to enamel. A three points bending test was used to investigate the physical mechanical property of resin cements. Tensile bond strength (TBS) was measured after the retainer was bonded to enamel by the resin cements. The fractured surface was observed by SEM to analyze the failure mode. Materials and Methods: C & B MetaBond (CB) and Multibond II (MB) were employed as the MMA-based resin cement. Resicem (RC) was used as the composite resin cement. Self-adhesive resin cements used were RelyX TM Unicem Cliker (UC) and Clearfil SA Luting (SL) and Maxcem (MC). A metal retainer was fabricated from 12 %Au-Ag-Pd alloy. The facial surface of a bovine incisor was ground to prepare the enamel surface. The prepared enamel was either conditioned according to the manufacturer's instructions or etched with phosphoric acid for 15 seconds followed by the conditioning of the enamel. The metal retainer was adhered to the processed enamel with the resin cements. TBS was determined after storage in 37℃ water for 24 hours or 37℃ water for 24 hours followed by thermal cycles (TC). The fractured surface was observed with SEM. Results: The three points bending tests were 71.8 MPa for SB, 70.8 MPa for MB, 124.6 MPa for RC, 88.8 MPa for UC, 109.7 MPa for SL, and 84.0 MPa for MC. The TC load decreased TBS with SB, while phosphoric acid etching increased TBS with SL, MC and UC. Although there was little change in TBS with MB and RC, improved adhesion by phosphoric acid etching was suggested from the observation of the fracture surface. Conclusion: As for the resin cements of the self-adhesive type and self-etching primer type, pre-etching of enamel improved the bonding properties of resin cements. And the resin cement using the automatic mixing tip had lower degradation through the TC load than resin cement not using it.
