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.

Tape‐casting technique can prepare β‐TCP sheets with uniform thickness and flexibility

“…The preparation of β‐TCP sheets using the tape‐casting technique is influenced by various processing parameters, such as the ratio of binder/plasticizer/solvent, casting speed, blade gaps, etc. Kim et al22 reported that the mechanical properties of alumina‐glass dental composite prepared by using the tape‐casting method were influenced by the ratio of alumina powder, binder, and plasticizer. Tok et al17 found that a higher degree of accuracy in tape thickness can be obtained by casting at a lower casting speed.…”

“…The dispersant used in the present first slurry consists primarily of poly(acrylic acid). The binder and plasticizer in the second slurry consist primarily of poly(acrylic acid)19 and polyethylene glycol,20, 22 respectively. There are several reports related to the composition of dispersant, binder, and plasticizer.…”

“…There are several reports related to the composition of dispersant, binder, and plasticizer. Kim et al22 used polyvinyl alcohol as a binder. They suggested that the use of polyvinyl alcohol as a binder and polyethylene glycol as a plasticizer are not adequate for the preparation of aqueous‐based tapes, particularly for crown forming applications.…”

“…The slurry for the tape‐casting method is composed of ceramic powders, dispersants, binders, and plasticizers. Kim et al22 prepared an alumina–glass dental composite using the tape‐casting method and found that the mechanical properties of the composite were influenced by the ratio of tape constituents; in other words, the ratio of alumina powder, binder, and plasticizer influenced the mechanical properties of the composite.…”

Near net-shape fabrication of alumina glass composites

“…7 For further reduction of the shrinkage, it is essential to lower both the presintering and the infiltration temperature. Many studies on melt-infiltrated alumina glass composites have been reported in literature, 3,4,[9][10][11] but all the glasses used in these investigations are based on the lanthanum-aluminosilicate glass, 7 where a minimum infiltration temperature of 1100 • C is required. Therefore, in order to reduce the fabrication temperature, it is necessary to develop new glasses that allow infiltrating alumina at lower temperature.…”