Many one-piece zirconia implants work with feldspar ceramic. But a new polymer infiltrated hybrid ceramic characterized by a low elastic modulus also may be considered as a potential material for implant-supported single crowns. One recent study evaluated the loading capacity of these hybrid ceramic single crowns on one-piece zirconia implants with respect to the cement type.
The researchers performed fractured load tests on standardized molar crowns milled from hybrid or feldspar ceramic, cemented to zirconia implants with a machined or etched intaglio surface using 4 different resin composite cements. Next, the researchers measured the flexure strength, elastic modulus, indirect tensile strength, and compressive strength of the cements.
During statistical analysis using 2-way analysis of variance (P = 0.05), the hybrid ceramic showed statistically higher fracture load values than the feldspar ceramic. The fracture load values and compressive strength values of the respective cements also were correlated. Adhesive cement (1,253 +/- 148 N) achieved the highest fracture load values. The etching of the intaglio surface did not improve the fracture load.
The researchers concluded, then, that the loading capacity of hybrid ceramic single crowns on one-piece zirconia implants exceeds that of feldspar ceramic. Practitioners should use self-adhesive or adhesive cements with a high compressive strength to achieve maximum loading capacity for permanent cementation of full-ceramic restorations on zirconia implants.
The study, “Loading Capacity of Zirconia Implant Supported Hybrid Ceramic Crowns,” was published by Dental Materials. It was written by Nadja Rohr, Nicola U. Zitzmann, and Jens Fischer of the University of Basel in Switzerland and Andrea Coldea of VITA Zahnfabrik, Germany.