Influence of misfit on the occurrence of veneering porcelain fractures (chipping) in implant‐supported metal‐ceramic fixed dental prostheses: an in vitro pilot trial

Objective Technical complications such as veneer fractures are more common in implant‐supported than tooth‐supported restorations. The underlying causes have not been fully identified. The aim of this study was to evaluate whether misfit between the restoration and the implant may affect the risk of veneer fractures. Materials and methods Twenty standardized five‐unit implant‐supported metal‐ceramic fixed dental prostheses (FDP)s were manufactured and fixed in acrylic blocks. The test group consisted of ten FDPs fixed with a 150‐μm misfit at the distal abutment. The remaining ten FDPs were fixed without misfit and acted as a control group. All FDPS underwent cyclic loading for a total of 100,000 cycles at 30‐300 N. The FDPs were checked for cracks or chip‐off fractures regularly. After cyclic load, the retorque value of all abutment screws was checked. Results Cracks within the veneering porcelain were noted in nine FDPs in the test group and one FDP in the control group. This difference was statistically significant (P