TENSILE BOND STRENGTH OF RESIN LUTING CEMENT TO A PORCELAIN-FUSING NOBLE ALLOY

This study evaluated the tensile bond strength of resin composites to a noble alloy for ceramic bonding after various surface treatments. Th e flat end of bars cast in the alloy were used as test specimens. Eigh teen clinically relevant combinations of luting agent, airborne partic le abrasion, and surface treatment were applied. After surface treatme nt, two bars were bonded together. Resin cement, either dual-polymeriz ing (Twinlook) or chemically polymerizing (Panavia EX, Panavia 21, or RBBC), was used as a luting agent. The specimens were subjected to 1,0 00 thermal cycles between 15 degrees C and 60 degrees C before tensile bond strength testing. The highest median bond strengths were obtaine d using the Silicoater MD method/Twinlook (20.6 to 26.1 MPa) or with t in-plating/ Panavia EX (24.0 MPa), but more low values were recorded a mong the latter specimens. Tin-plating/Panavia 21 gave median tensile bond strengths (18.1 MPa) similar to tin-plating/Panavia EX. The Silic oater MD method resulted in similar bond strengths with or without the addition of a layer of Opaquer. The traditional Silicoater method (8. 0 to 12.4 MPa) gave significantly lower median tensile bond strength v alues, and the lost sugar crystals method resulted in a tensile bond s trength of 15.4 MPa.