Biological Considerations on the Use of Zirconia for Dental Devices

Abstract

Zirconium oxide, known as zirconia, is a ceramic material with optimal esthetical and mechanical properties. Zirconia stabilized with yttrium oxide has the best properties for medical uses. A stress on ZrO z surface creates a crystalline modification that opposes to propagation of cracks. Zirconia core for fixed partial dentures (FPD) on anterior and posterior teeth and on implants are now available. Clinical evaluations after 3 years report good percentage of success for zirconia fixed partial denture. Zirconia biocompatibility was studied in vivo and in vitro by orthopedic research; no adverse responses were reported on insertion of ZrO z samples in bone or muscle. In vitro experimentation showed absence of mutation and a good viability of cells cultured on this material. Zirconium dioxide is white, has good wear resistance surface grinding could reduce toughness (6); also Kosmac and mechanical properties similar to a metal; it is also confirmed this assertion reporting a lower mean strength known as Zirconia. zr0 2 crystals and can be organized of zirconium oxide after surface grinding (7). Moreover, in different patterns: Monocline (M), Cubic (C) and ageing is another important feature of Zr0 2 ; Swan Tetragonal (T). In order to stabilize zirconium oxide it is reported that zirconia can lose its mechanical features if necessary to add other metallic oxides, such as MgO, CaO placed in a wet enviroment for a long time (8). and YP3; Yttrium stabilized zirconia nowadays is the

Development of a New Zirconia-Toughened Alumina: Promising Mechanical Properties and Absence of In Vitro Carcinogenicity

“…Weibull modulus was then determined on the same material testing thirty bars. In order to evaluate the effects of the sample's volume on the reliability, bars with different dimensions (2x2.5x25mm 3 and 3x4x45mm 3 ) were prepared. The results demonstrated that the tested material is highly reliable (Weibull modulus is higher than 10) and can be also defined a "defect-free" material because it showed the same average flexural strength (1400 MPa) with both types of the bars (Table III).…”

“…On this basis, the possible chronic effects, potentially related to low debris production in time, are relevant for these materials. Zirconia ceramics elicit higher mechanical properties when compared to alumina (2) and are currently used for dental devices due to their better mechanical and biological properties (3). In the past high interest was given to this material also in orthopaedics, and about 900,000 zirconia ball heads have been implanted in total hip arthroplasties, even if a debate arose regarding the potential radioactivity and carcinogenicity of zirconia source.…”

In Vitro Evaluation and Comparison of the Translucency of Two Different All-Ceramic Systems

“…This finding can be attributed to the crystalline content of zirconia in order to achieve a greater strength results, but at the same time the inhomogeneity of crystals causes different refractive indices and therefore poor translucency (22,23). In order to improve the optical behavior of the zirconia restorations, shaded zirconia cores were developed (24)(25)(26).…”

Analysis of Stress and Fracture Strength of Zirconia Implants after Cyclic Loading

“…Zirconia is radiopaque and because of its color, similar to that of the natural tooth, it is the material of choice for aesthetically critical areas of the mouth 6 . Studies 7,8 have demonstrated that the material appears to be capable of withstanding loads over the long term and its biocompatibility as a dental implant material has also been demonstrated in vitro and in clinical investigations 9 . However, most studies are limited to the evaluation of the market available zirconia implants compared with titanium implants, which do not have the same design.…”