Effect of aging on fracture resistance and torque loss of restorations supported by zirconia and polyetheretherketone abutments: An in vitro study.

Abstract Statement of problem New materials have been developed for digital processing, including implant abutments, but studies on their mechanical properties are lacking. Purpose The purpose of this in vitro study was to compare the effect of aging on the fracture resistance, failure mode, and torque loss of restorations made of zirconia and ceramic-reinforced polyetheretherketone (PEEK) abutments with titanium bases. Material and methods Titanium-based PEEK and zirconia abutments were milled and veneered with composite resin or feldspathic porcelain in the form of maxillary first premolars (n=10). All the specimens were subjected to an aging process and were assessed after every 250 000 cycles under a stereomicroscope, and torque loss was recorded with an electronic torque meter. Fracture resistance was measured under static load (crosshead speed of 1 mm/min), and failure modes and final torque were determined. A t test was conducted for statistical analyses (α=.05). Results The fracture resistance of the zirconia restorations was significantly greater than the PEEK-based restorations (P=.001). Torque losses were not significantly different after aging (P=.18); however, significant difference was recorded after the fracture test (P=.007). The effect of fracture load was significantly greater for the zirconia group (P Conclusions Ceramic-reinforced PEEK abutments had acceptable resistance to fracture, a favorable failure mode, and successfully sustained the aging process.