Mechanical properties of alumina-glass dental composites

A near net-shape process was developed for fabricating all ceramic dental restorations. Preforms from uniaxially pressing, Robocasting (RB) and 3-dimensional printing (3DP) processes were employed to implement the process. All these preforms can be well infiltrated by a model glass. Investigations on sintering effects showed that the shrinkage and the green density of preforms increase while the relative density of infiltrated composites decreases with increasing presintering temperature. Composites from pressed preforms exhibit an average fracture strength of approx =340 MPa regardless the presintering temperature, while a strength of 287 MPa was recorded for composites from RB preforms. Subcritical crack growth (SCG) behavior of the composite was characterized by the dynamic fatigue test, and the SCG exponent n was determined to be 20.