Objective: Characterize the microstructure, composition, and some physical properties of the ceramic VM13 (Vita Zahnfabrik, Germany). Methods: Vita VM13 specimens were fabricated according the manufacturer's instructions and ISO6872 standard and polished through 1µm alumina abrasive. Semi-quantitative and qualitative analyses were performed using scanning electron microscopy (SEM), backscattered imaging (BSI), electron dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The elastic modulus (E) and Poisson's ratio (v) were determined using ultrasonic-time-of-flight data measured in a high-frequency ultrasonic pulser/receiver (Nuson, Inc., Boalsburg PA). Vickers indentation (Shimadzu HMV-2000) and the indentation fracture technique (IF) were used to calculate values for hardness (H) and fracture toughness (K_IC) using H = 0.5 (P/a²) and K_IC = 0.067 (E/H)^0.4 Ha^1/2 (c/a)^-3/2 where “P” is the indentation load (9.8 N for 20 s), “a” is the average indentation half-diagonal and “c” is the size of the radial cracks (n=30). The 3-point bending test was used for determination of the flexural strength (σf)(n=20) according to ISO6872. Results: v = 0.25±0.01; E = 60±2 GPa; σf= 120±10.9 MPa; H = 7.5±0.2 GPa; and K_IC = 1.02±0.2 MPa•m¹/². SEM, BSI and EDS analyses revealed a feldspathic ceramic with the following average composition: Si(K) 15.9%; Al(K) 13.5%; K(K) 15.9%; Na(K) 6.8%; Ca(K) 2.4%; Mg(K) 0.4%; Ba(L) 4.4%. Leucite crystals were found in XRD analysis. Conclusion: Vita VM13 is a leucite-base ceramic that has the studied properties comparable to other feldspathic ceramics.

Partially supported by CNPq do Brasil grant # 300659/2003-2.

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