JUDSON C. H,CKEV SCIENTIFIC WRITING AWARD WINNER Shear bond strength to feldspathic porcelain of two luting cements in combi- nation with three surface treatments

Statement of problem. Although selection of clinically reliable bonding system is essential, limited information concerning the combination of durable ceramic bonding and luting agents is available. Purpose. This in vitro study was conducted for the purpose of evaluating bond strengths of ceramic bonding materials in conjunction with their initiation and silane-activation modes. Material and methods. Disk-shaped fired porcelain specimens were air-abraded with alumina, then bonded with six combinations of three silane priming and two luting agents; specimens were also bonded with two luting cements without priming. Shear bond strengths were determined both before and after thermocycling. Results. For the two unprimed control groups, as well as two of the groups bonded with Panavia 21 cement (Clearfil Porcelain Bond and Panavia 21; Panavia Ceramic Primer and Panavia 21) the reduction in bond strengths after thermocycling was remarkable as compared with the corresponding prethermocycling groups (p < 0.05). A dual-cured luting cement (Clapearl DC) used with each of three silane priming materials (Clapearl Bonding Agent, Clearfil Porcelain Bond, and Panavia Ceramic Primer) exhibited consistent shear bond strength greater than 30 MPa after 20,000 thermocycles. Conclusion. The above three systems appeared to be useful for the long-term clinical success of feldspathic porcelain restorations. (J Prosthet Dent 1997;78:511-17.