Has zirconia made a material difference in implant prosthodontics? A review

Objective. The main goal of this review is to provide an in-depth description of published work on the application of zirconia for dental implansts and restorations on titanium implants, with an emphasis on clinical studies from the past dozen years with at least 1-year follow-up. Methods. Online databases (Pubmed, Science Direct, Web of Science) were consulted on this topic. Published work from 2007 to 2019 was collected, analyzed and pertinent articles were selected for inclusion on this review. Results. No clear superiority has been documented in biocompatibility, osteoconductivity, physical properties or allergenicity with zirconia implants compared to titanium, notwithstanding an esthetic benefit. While short-term studies have been promising, larger multicentered, longitudinal and randomized clinical trials with success data are required to validate zirconia as a viable alternative to the titanium implant and its design. Zirconia abutments with a titanium base have revealed a high survival rate and show no difference to metal. Bi-layered zirconia ceramic restorations are a valid treatment alternative to metal ceramic implant restorations for single crowns with similar biological complications and enhanced esthetics. Monolithic zirconia restorations hold promise to address the chipping incidence of the bi-layered ceramic restoration, but longer-term studies are necessary, and work needs to be done to improve their esthetics. The gingival feldspathic porcelain veneered monolithic zirconia complete arch prosthesis versus a resin metal prosthesis, in medium-term studies, offers a high survival rate and low mechanical complication rate, reduced laboratory costs, superior durability and wear characteristics, enhanced fit due to digital fabrication, availability of a digital file for duplication in the future, acrylic try-for adjustment and approval, and reduced plaque and biofilm accumulation. Significance. Zirconia is a versatile material for implant prosthodontic application. Longer-term multi-centered studies are needed to assess success criteria and patient-related outcomes measurements. Monolithic zirconia offers enhanced mechanical properties for implant restorations, but development is needed to optimize esthetics. (C) 2019 Published by Elsevier Inc. on behalf of The Academy of Dental Materials.