Dynamic fatigue and strength characterization of three ceramic materials

Abstract

Fracture strength and fatigue parameters of three ceramic materials submitted to dynamic fatigue were evaluated. A machinable leucite-reinforced dental ceramic, aluminum oxide, and yttria-stabilized zirconia (YSZ) were tested. The inert strength of the materials was determined in air (25 degrees C) at stressing rates of 70, 250, 400 MPa/s for Porcelain, Alumina and YSZ respectively. The data was analyzed using a two-parameter Weibull distribution. The Weibull modulus (m) and the characteristic of fracture (sigma0) parameters were determined for each material. Specimens were also tested in 3-point bending at different stressing rates in distilled/deionized water at 37 degrees C (dynamic fatigue) in order to calculate the fatigue parameters n and ln B. The strength for each material was characterized using Strength-Probability-Time (SPT) diagrams for 1 day, 1 year and 10 years. YSZ showed a high-fracture strength sigma0 (1,459 MPa) at a failure probability of 63.2% and high resistance to subcritical crack growth. YSZ and alumina showed better resistance to slow crack growth than porcelain, indicating less susceptibility to strength degradation by stress corrosion. Lifetime predictions after 10 years indicate a reduction of 50%, 36% and 29% in strength for porcelain, alumina and YSZ respectively. YSZ seems to be a very promising material for long-term dental and biomedical applications.

Influence of surface treatment of yttria-stabilized tetragonal zirconia polycrystal with hot isostatic pressing on cyclic fatigue strength

“…However, this may induce phase transformation in zirconia, from tetragonal to monoclinic, as well as superficial microcracks, resulting in change in its mechanical properties in terms of both static and fatigue strength [20][21][22] . Takano However, the influence of surface treatment on the fatigue strength of Y-TZP fabricated by HIP processing (HIP Y-TZP) remains to be determined, even though this is an important factor in its durability in the oral environment 8,24,25) . Therefore, the aim of this study was to evaluate the influence of surface treatment of HIP Y-TZP on cyclic fatigue strength.…”

Influence of crown design and material on chipping-resistance of all-ceramic molar crowns: An in vitro study

“…The combination of a moist environment and stresses during functioning increases the potential for crack propagation and reduces the load required for failure. 23 The test used in the present study was performed while the specimens were maintained under water in order to counteract heat buildup at the point of contact due to friction, and to keep the test conditions clinically-relevant. The load cycle selected (50-450 N) is within the range of occlusal biting forces encountered in the posterior region.…”

Comportamento mecânico de cerâmicas utilizadas na confecção de próteses parciais fixas

“…Tinschert et al (2000) relataram um valor alto de módulo de Weibull para a YZ (18,4). Entretanto, outros estudos encontraram valores mais baixos de módulo de Weibull, variando entre 10 e 16 (Liu;Chen, 1991;Kosmac et al, 1999;Luthardt et al, 2002;Teixeira et al, 2007;Yilmaz et al, 2007).…”

“…Os valores de módulo de Weibull dos materiais de infra-estrutura obtidos no presente estudo estão na mesma faixa de valores encontrados na literatura, entre 9 e 18 para cerâmicas a base de zircônia e alumina (Zeng et al, 1996;Kosmac et al, 1999;Tinschert et al, 2000Tinschert et al, , 2007Chong et al, 2002;Luthardt et al, 2002;Teixeira et al, 2007;Yilmaz et al, 2007). Tinchert et al (2007) A resistência à fratura com uma probabilidade de falha de 63,5% é descrita pelo valor de σ 0 .…”

“…Os altos valores de n obtidos pelos materiais YZ e AL mostram que a microestrutura das cerâmicas policristalinas resulta em uma barreira muito mais eficiente ao crescimento lento de trincas em meio úmido do que as porcelanas e os compósitos. Teixeira et al (2007) Marocho et al, 2010).…”