Fracture strength of implant-supported monolithic crowns after aging in a mastication simulator

The fracture strength of implant-supported monolithic CAD/CAM crowns under approximate clinical conditions and how their fracture strength is affected by cement type remain unclear. The present study investigated the fracture resistance of implant-supported polymer-infiltrated ceramic and zirconia-reinforced lithium silicate glass-ceramic crowns cemented with two different cement types after aging in a mastication simulator. RelyX Ultimate Clicker (3M ESPE) as adhesive resin cement, Panavia SA Cement Plus (Kuraray Noritake) as self-adhesive resin cement, and two monolithic materials (A1-T for Enamic and M1-HT for Suprinity; both Vita Zahnfabrik) were tested. Forty CAD/CAM-produced monolithic implant-supported crowns for a maxillary right second premolar were prepared, and crowns were cemented to the straight implant abutments with each cement, then subjected to dynamic load cycling (480,000 cycles) and thermocycling (about 4,000 cycles) in a mastication simulator. Crown fracture resistance was analyzed by the load-to-failure test. Crown-abutment samples were loaded until fracture. No significant difference was observed in the fracture load of the crowns among the groups. The results suggest that both monolithic restoration materials could be an alternative for implant-supported cement-retained restorations, regardless of cement type.