Fretting fatigue wear behavior of Y-TZP dental ceramics processed by non-conventional microwave sintering

Abstract

[EN] The fretting wear behavior of self-mated Y-TZP dental materials obtained by non-conventional microwave and conventional sintering has been investigated. Two 3Y-TZP materials, a widely utilized commercial dental ceramic (LAVA) and a lab-prepared 3Y-TZP powder based equivalent have been assessed. Relative density and mechanical properties as well as the grain size variations upon sintering have been evaluated. After exposure to selected gross slip regime fretting wear conditions, the wear tracks have been characterized allowing the measurement of the coefficient of friction, track profiles, and pit features. The results indicate thaT microwave sintering results in a similar fretting wear behavior as observed for conventional sintered 3YTZP, since the measured volumetric wear loss is of a comparable order of magnitude. Regarding the influence of the grain size, the analysis revealed that a large grain size (>300 nm) results in an increased wear volume and that a higher resistance to fretting wear is constrained to a midrange particle size. Since the fracture toughness of all investigated ceramic grades was comparable, the influence of the fracture toughness could not be assessed. Abrasive grooving, delamination and microcracking have been identified as major wear mechanisms inside the wear tracks for both conventional and microwave sintered 3Y-TZP. In general, microwave sintering can provide 3Y-TZP dental materials with a comparable fretting wear resistance as that observed for conventional sintering using lower dwell sintering temperatures and a shorter processing time.