A comparison of mechanical properties of all-ceramic alumina dental crownsprepared from aqueous- and non-aqueous-based tape casting

Alumina-glass dental composites were prepared by aqueous- and non-aqueous-b ased tape casting and sintering at 1120 degrees C, followed by glass infilt ration at 1100 degrees C. Flexural strength and fracture toughness of the c omposites were investigated in terms of influence of tape constituents, nam ely, alumina powder, binder, and plasticizer on the mechanical properties. For the alumina-glass composites prepared from the aqueous-based tapes, bot h strength and toughness increased with increasing alumina fraction ratio i n tape constituents including organic substances, a/a + o, and binder conte nt ratio in binder/binder + plasticizer mixture, b/b + p. For the composite s prepared from the non-aqueous-based tapes, on the other hand, both streng th and toughness increased with increasing the a/a + o ratio but decreased with increasing the b/b + p ratio. These observations were consistent with influence of the constituents on mean alumina particle distance in tapes, s uggesting that high strength of the glass infiltrated alumina composites is related to toughening by crack bowing. The optimized strength of the aqueo us and nonaqueous tape cast composites was 559 and 508 MPa, and the fractur e toughness was 3.3 and 3.1 MPam(1/2), respectively. (C) 2000 John Wiley & Sons, Inc.