Efficacy of Different Surface Treatments for Intraoral Repair of Veneered Zirconia Frameworks.

PURPOSE: To evaluate the efficacy of different surface treatments on the repair of veneered zirconia ceramics.

MATERIALS AND METHODS: Forty-eight zirconia disks were divided into three groups according to the method of surface treatment: polished surface, air abraded, or ground using a special silicon carbide bur (SiC Grinding Bur). All specimens were primed using a primer containing MDP (Cimara Zircon, Voco) and then bonded to composite in Plexiglas tubes using dual-curing adhesive resin (Bifix QM, Voco). Each of the three groups was further divided into two subgroups (n = 8) stored either in water at 37°C for 3 days without thermocycling or stored in water at 37°C for 150 days with an additional 37,500 thermocycles between 5°C and 55°C. After storage, tensile bond strength (TBS) was measured in a universal testing machine.

RESULTS: After 3 days of storage, silicon carbide bur and air-abraded groups showed high TBS that ranged from 32.7 to 41.0 MPa (p ≤ 0.05). After 150 days of storage with thermocycling, the air-abraded group showed the most durable TBS (34.8 MPa), while the silicon carbide bur group showed a significant reduction in TBS (21.2 MPa); in the polished control group, specimens all debonded spontaneously during storage (p ≤ 0.05).

CONCLUSION: Repair of zirconia ceramic after chipping of its veneers showed durable TBS when surface conditioning with air abrasion or roughening of the zirconia surface with a silicon carbide bur was provided.