Abstract:

Objective:The purpose of this study was to determine the thermal, mechanical properties and density of the composite infiltrated with GI-Ⅱtinted infiltration glass.Methods: The bar-shaped aluminum oxide and glass/alumina composite specimens with the size of 20 mm×5 mm×5 mm were prepared, with two free-end surfaces perpendicular to the long axis of the specimens and parallel to each other. The thermal expansion curves were obtained on a TMA2940 thermal analyzer with heating rate of 5℃/min and temperature range of 25℃ to 1000℃. The bar-shaped specimens with the size of 25 mm×5 mm×2 mm were fabricated and employed to test the density using Archimede’s method. The flexural strength, elastic modulus were measured by means of 3-point bending test with the same specimens. The fractured specimens were indented with Vicker’s diamond pyramid under load of 49 N for 15 seconds to determine the hardness and indentation fracture toughness.Results: The thermal expansion coefficient of the glass/alumina composite was 7.620×10+{-6}℃+{-1}(25～500℃), which was higher than that of Vitadur alpha veneering porcelain. The 3-poit flexural strength, elastic modulus, Vicker’s hardness, indentation fracture toughness and density were 389.6 MPa, 92 GPa, 9.409 GPa, 3.2425 MNm+{-3/2} and 3.662 g/cm+3 respectively.Conclusion: The thermal expansion of the GI-Ⅱ glass/alumina composite is compatible with that of Vitadur alpha veneering porcelain, and the material could meet the strength demands for clinical use.

Key words: glass/alumina composite, mechanical properties, infiltration glass