Mechanical properties and porosity of dental glass-ceramics hot-pressed at different temperatures

• Published in: Materials research (São Carlos, São Paulo, Brazil) São Paulo, Brazil), 2008-09, Vol.11 (3), p.301-306
• Main Authors: Gonzaga, Carla Castiglia, Cesar, Paulo Francisco, Okada, Cristina Yuri, Fredericci, Catia, Beneduce Neto, Flávio, Yoshimura, Humberto Naoyuki
• Format: Article
• Language: English
• Subjects: dental glass-ceramics; ENGINEERING, CHEMICAL; injection temperature; MATERIALS SCIENCE, MULTIDISCIPLINARY; mechanical properties; METALLURGY & METALLURGICAL ENGINEERING; porosity
• ISSN: 1516-1439; 1980-5373; 1516-1439
• DOI: 10.1590/S1516-14392008000300012

An attempt was made to evaluate the biaxial-flexural-strength, Vickers hardness, fracture toughness, Young's modulus, Poisson's ratio and porosity of two commercial glass-ceramics, Empress (E1) and Empress 2 (E2), as a function of the hot-pressing temperature. Ten discs were hot-pressed at 1065, 1070, 1075 and 1080 C for E1; and at 910, 915, 920 and 925 C for E2. The porosity was measured by image analyser software and flexural strength was determined using the piston-on-three-balls method. Fracture toughness and Vickers hardness were determined by an indentation method. Elastic constants were determined by the pulse-echo method. For E1 samples treated at different temperatures, there were no statistical differences among the values of all evaluated properties. For E2 samples treated at different temperatures, there were no statistical differences among the values of flexural strength, Young's modulus and Poisson's ratio, but Vickers hardness and fracture toughness were significantly higher for 910 and 915 C, respectively. The mean value of porosity obtained for E2 for 925 C was significantly higher compared to other temperatures. 40 refs.