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

Abstract

Alumina-glass dental composites were prepared by aqueous- and non-aqueous-based tape casting and sintering at 1120 degrees C, followed by glass infiltration at 1100 degrees C. Flexural strength and fracture toughness of the composites were investigated in terms of influence of tape constituents, namely, alumina powder, binder, and plasticizer on the mechanical properties. For the alumina-glass composites prepared from the aqueous-based tapes, both strength and toughness increased with increasing alumina fraction ratio in tape constituents including organic substances, a/a + o, and binder content ratio in binder/binder + plasticizer mixture, b/b + p. For the composites prepared from the non-aqueous-based tapes, on the other hand, both strength 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, suggesting that high strength of the glass infiltrated alumina composites is related to toughening by crack bowing. The optimized strength of the aqueous and nonaqueous tape cast composites was 559 and 508 MPa, and the fracture toughness was 3.3 and 3.1 MPam(1/2), respectively. (C) 2000 John Wiley & Sons, Inc.