Fracture of Zirconia Abutments in Implant Treatments: A Systematic Review.

Purpose: The purpose of this systematic review was to identify and summarize clinical studies related to the fracture of zirconia abutments in implant treatments.
Material and Methods: Medline, Embase, and Cochrane library searches were performed and complemented by manual searches from database inception to February 11, 2018, for title and abstract analysis.
Results: Initially, 645 articles were obtained through database searches. Fifty-three articles were selected for full-text analysis, and 15 studies met the inclusion criteria. The selected studies were analyzed regarding fracture rate, abutment-implant connection, time point of fracture, location of critical crack, causes, managements, and preventive measures with respect to zirconia abutment fracture.
Conclusions: Lower fracture rates were reported for internal connection with metal component (2-piece) zirconia abutments compared with external and internal full-zirconia connection (one-piece) zirconia abutments. Overpreparation and overload should be avoided in case of zirconia abutments.