Fatigue Resistance of Different Customized Crown-Abutment Combinations for Single Implant-Supported Restorations

Abstract

This in-vitro study was designed to evaluate the fatigue and fracture resistance of different CAD/CAM customized crown-abutment combinations using 2 materials; monolithic zirconia and monolithic lithium disilicate and using 2 designs; hybrid-abutment-crowns (one-piece) and hybrid-abutments plus monolithic crowns (two-piece). Thirty-two implants; were embedded perpendicularly in an auto-polymerizing resin. Thirty-two crown-abutment combinations simulating a maxillary first premolar were designed and milled using a CAD/CAM system. These combinations were divided into two main groups according to type of material (n=16): zirconia and lithium disilicate. Each group was sub-divided into two subgroups according to design (n=8): hybrid-abutment-crown (one-piece) and hybrid abutment plus monolithic crown (two-piece). Titanium inserts were cemented to their respective abutments using self-curing resin cement after surface treatment of the bonding surfaces. Titanium and zirconia bonding surfaces