Effect of sintering duration on the sliding-wear resistance of 3Y-TZP dental ceramics

Zirconia doped with 3 mol% yttria (3Y-TZP) is widely employed in prosthetic dentistry. The standard routine in the manufacture of prostheses involves subtractive machining of a commercial presintered block, followed by pressureless sintering up to full densification using one of the heat treatments indicated by the supplier, so as to obtain adequate strength. Usually, however, little information is provided on how these treatments affect the wear resistance. The present work therefore investigated how three sintering cycles of different durations recommended by a commercial supplier affected the microstructure and long-term degradation in the form of sliding-wear of the resulting 3Y-TZP ceramics. It was found that the three cycles essentially resulted in the same wear behavior (ie, wear modes and mechanisms, as well as specific wear rate 5 center dot 10(-6) mm(3)/Nm). The results are analyzed within the framework of existing abrasive wear models, and implications for the manufacture of durable prostheses are discussed.