Biaxial flexural strength, elastic moduli, and x-ray diffraction characterization of three pressable all-ceramic materials

• Published in: The Journal of prosthetic dentistry 2003-04, Vol.89 (4), p.374-380
• Main Authors: Albakry, Mohammad, Guazzato, Massimiliano, Swain, Michael Vincent
• Format: Article
• Language: English
• Subjects: Aluminum Silicates - chemistry; Analysis of Variance; Ceramics - chemistry; Crystallography; Dental Porcelain - chemistry; Dental Stress Analysis - instrumentation; Dentistry; Elasticity; Humans; Lithium Compounds - chemistry; Matched-Pair Analysis; Materials Testing; Pliability; Stress, Mechanical; Surface Properties; X-Ray Diffraction
• ISSN: 0022-3913; 1097-6841
• DOI: 10.1067/mpr.2003.42

Statement of Problem. Before the release of an advanced ceramic material, independent assessment of its strength, elastic modulus, and phase composition is necessary for comparison with peer materials. Purpose. This study compared the biaxial flexural strength, elastic moduli, and crystalline phases of IPS Empress and Empress 2 with a new experimental ceramic. Material and Methods. Twenty standardized disc specimens (14 × 1.1 mm) per material were used to measure the biaxial strength. With a universal testing machine, each specimen was supported on 3 balls and loaded with a piston at a crosshead speed of 0.5 mm/min until fracture. Three standardized bars (30 × 12.75 × 1.1 mm) for each material were prepared and excited with an impulse tool. The resonant frequencies (Hz) of the bars were used to calculate the elastic moduli with the equation suggested by the standard ASTM (C 1259-94). X-ray diffraction with Cu Kα at a diffraction angle from 20 to 40 degrees was used to identify the crystalline phases by means of a diffractometer attached to computer software. The data were analyzed with 1-way analysis of variance followed by pairwise t tests (P