Comparative In Vitro Study of Implant-Supported Restorations: Implant-Abutment Complex With and Without Prosthetic Finishing Line

Abstract

The aim of this study was to evaluate the mechanical behavior of implant-supported cemented restorations placed on two types of abutment design, with and without a prosthetic finish line, evaluating fracture resistance and the type of fracture produced in the abutment-crown complex. Eighty zirconia restorations supported by tapered implants were divided into two groups: group I, with 40 zirconia crowns cemented onto individualized zirconia abutments with a chamfered finish line (1 mm deep); and group II, with 40 zirconia crowns cemented onto individualized zirconia abutments without a finish line. All specimens underwent thermocycling and dynamic loading before static load testing to evaluate their fracture resistance. Fracture resistance values (N) and the type of fracture were analyzed. The mean fracture resistance was 462.1 ± 66.3 N in group I and 343 ± 40 N in group II. In group I, fractures were produced in the prosthetic fixation screw; in group II, all mechanical failures were produced in the transepithelial abutment's cervical area. Group I specimens showed greater fracture resistance than group II. The fracture type in group I occurred in the prosthetic screw. Group II fractures occurred in the zirconium oxide abutment.