Influence of roughening procedures and priming agents on shear bond strength of CAD/CAM materials to zirconia frameworks

This study investigated the influence of roughening procedures and application of primers on shear bond strengths of CAD/CAM composite resin material or ceramic material to zirconia frameworks. A CAD/CAM composite resin block (Katana Avencia Block; AVE) and lithium disilicate glass-ceramic block (IPS e.max CAD; IEC) were used as veneer materials. The veneers were divided into three surface treatment groups; HF, hydrofluoric acid etching; AB, airborne-particle abrasion; and CON, no surface treatment. Each veneer was primed with four agents: Clearfil Porcelain Bond Activator (ACT), Clearfil Photo Bond (CPB), Clearfil Photo Bond with Porcelain Bond Activator (CPB+ACT), and no priming (UP). The zirconia frameworks and AVE or IEC veneers were resin-bonded. In the AVE specimen, AB treatment showed significantly higher shear bond strength than the other treatments at 0 and 20,000 thermocycles, except for UP and CPB+ACT groups at 20,000 thermocycles. Airborne-particle abrasion is necessary for resin bonding to Avencia blocks.