To study the mechanical and optical properties of a new nanocrystalline yttria-stabilized zirconia (PX242A Tosoh Japan). The influence of heating rates on its properties and its potential use as a dental ceramic were also evaluated. Samples of PX242A were divided into 4 groups according to heating rates : group H1 (100oKh−1); group H2 (200oKh−1); group H4 (400oKh−1); group H6 (600oKh−1). Group H0 (3Y-SBE Tosoh Japan) was made according to the manufacturer's recommendation as a control. The contrast ratio (CR), transparency parameter (TP) and total transmittance (TT) were measured by an Xrite spectrophotometer. The flexural strength and fracture toughness were also evaluated. The flexural strength and fracture toughness were found to be independent of the heating rate while the optical properties significantly increased when the heating rates were 600oKh−1, 200oKh−1 and 400oKh−1, but were not significantly different with 100oKh−1. A heating rate of 600oKh−1 is suggested as a time efficiency protocol, because it could provide desirable mechanical and optical properties, making zirconia suitable for clinical use.

Keywords: Heating rate, Transparency, Ceramic, Mechanical property, Zirconia