Abstract
As replacements for dental structures, yttria-stabilized zirconia polycrystalline (Y-TZP) ceramics have become increasingly important due to their characteristics and performance in service. An excellent combination of high strength and fracture toughness with moderate hardness can be useful to limit wear of interacting surfaces. Even though wear studies of Y-TZP materials are mostly concerned with hip-joint prostheses, wear of zirconia-based materials for odontological applications also needs to be investigated. Constant exposure to high levels of humidity, contact and friction with other surfaces during the mastication process, and loss of mechanical properties due to low-temperature degradation (LTD) of zirconia are important aspects that need to be considered when evaluating the wear of these materials. Several parameters allow the evaluation of wear, such as coefficient of friction (COF) and wear volume. The material consolidation processing has a direct impact on the mechanical properties. Non-conventional sintering methods, such as microwave sintering, have been developed to reduce sintering times and energy consumption, while maintaining or even improving the mechanical properties of the resulting materials. The aim of this work is to evaluate the wear behavior of two Y-TZP dental materials sintered via microwave and conventional sintering at different temperatures under reciprocating fretting fatigue conditions in a ball-on-plate setup. Moreover, the effect of LTD, as well as that of humidity during the fretting tests, is also investigated by determining the COF and wear volume. Qualitative wear track characterization is performed via Nomarski and confocal microscopy and profilometry.
