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Ceramic Based Biomaterials
Published in Yaser Dahman, Biomaterials Science and Technology, 2019
Zirconia is a biomaterial that is mostly used for the applications of endoprosthesis and dentistry. Ceramic dental implants have many advantages over metal implants such as minimal ion release, better aesthetics, elimination of potential allergy to metals, and most importantly it does not undergo corrosion (Zarone et al., 2011). Clinical studies have also been able to show that there is no difference in the performance of dental implants between zirconia and titanium (Apratim et al., 2015). Zirconia has gained popularity as a ceramic crown over metals since zirconia crowns are equally effective, improve the appearance of teeth due to their translucent properties, are durable, easy to wear, and long lasting. Zirconia crowns also last longer than other types of crown and help to preserve more of the original tooth since minimal preparation for zirconia crowns is required (Zarone et al., 2011). One of its downfalls is that zirconia can cause friction against other teeth, and the root of the tooth due to its strength and the nature of its surface (Apratim et al., 2015).
Biomaterials and Surface Modification
Published in Mohammad E. Khosroshahi, Applications of Biophotonics and Nanobiomaterials in Biomedical Engineering, 2017
Bioceramics are usually polycrystalline inorganic silicates, oxides, and carbides. The ceramic materials used are not the same as porcelain type ceramic materials, but rather are closely related to either the body’s own materials (e.g., calcium phosphate) or are extremely durable metal oxides. They are refractory in nature and possess high compressive strength. Bioceramics are classified into: inert, bioactive, and biodegradable materials (Park et al. 2004). Bioinert ceramics like alumina and zirconia maintain their physical and mechanical properties even in biological environments. Zirconia is highly wear resistant and tough; it undergoes stress-induced transformation toughening. A major application of zirconia ceramics is in total hip replacement (THR) ball heads. Ceramics such as phosphate and tricalcium phosphate (TCP) degrade when placed in a biological environment, and thus are considered biodegradable. Salts like hydroxylapatite (HA) can be crystallized from calcium phosphate. The main mineral of bone and teeth is HA, which explains its biocompatibility.
Materials for 3D Printing
Published in Rafiq Noorani, 3D Printing, 2017
Zirconia is being developed at Soligen, this material provides an increased cooling rate, similar to sand casting. Zirconia possesses resistance to thermal shock, wear, and corrosion in addition to a low-thermal conductivity property. Zirconia (ZrO2) transforms from a tetragonal to a monoclinic structure when it cools down from an elevated temperature. This transformation may initiate or propagate cracks in the part yielding in a possible failure of the material. However, adding CaO, MgO, or Y2O3 to zirconia will stabilize the cubic phase throughout various temperatures, thus avoiding the destructive phase transformation and creating a partially stabilized zirconia (PSZ). This PSZ ceramic also has enhanced strength, toughness, and reliability than the unstabilized zirconia. A newer development for Zirconia is called transformation-toughened zirconia (TTZ), which improves on PSZ by providing enhanced toughness. Table 5.4 below shows the general ceramic properties for alumina, PSZ, and TTZ.
Stress distribution on implant- supported zirconia crown of maxillary first molar: effect of oblique load on natural and antagonist tooth
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Lisliane Nara Rossi Leandro, Mateus Favero Barra Grande, André Antônio Pelegrine, Renato Sussumu Nishioka, Marcelo Lucchesi Teixeira, Roberta Tarkany Basting
For fabrication of implant-supported ceramic crowns, zirconia has been found to be the most suitable because of its high resistance to wear, corrosion, in addition to being biocompatible and opaque. The latter is an interesting feature in terms of masking a titanium metal abutment (Jung et al. 2021). Moreover, zirconia has demonstrated higher fracture resistance and flexural strength when compared with other ceramic materials, which makes it interesting for the dissipation of multidirectional stresses, and may have survival rates of 5 years longer than feldspathic/silica based ceramic crowns in posterior regions (Sailer et al. 2015). Although monolithic zirconia implant-supported crown is a good option for posterior regions of the maxilla and mandible due to its mechanical properties that support the loads in this region (Pathan et al. 2019), cracks can occur, representing between 8% and 25% of the problems observed, although fractures at the implant/ceramic interface rarely occur (Sasaki et al. 2015).
Effects of nano MgO addition on the mechanical, wear, and low-temperature degradation properties of 3Y-TZP composite ceramics
Published in Philosophical Magazine, 2022
Junwei Xia, Jin Zhang, Pan Luo, Guo Bai, Tong Lin, Songxia Li
Zirconia is used as a biological material for teeth or artificial bones, where materials of the same type will often rub against each other. Therefore, the evaluation of the material’s frictional properties is crucial. Here, commercially available zirconia grinding balls (6 mm diameter) were selected as the counter-abrasive balls. The load was 50 N, the friction speed was 50 mm/min, the length of the abrasion marks was 10 mm, and the test time was 60 min. The friction coefficient was tested using an MFT-4000 Material Surface Multifunctional Tester (State Key Laboratory of Solid Lubrication, Lanzhou, China), with the mass wear rate calculated using the following equation: where W is the mass wear rate (mg/Nm), △m is the amount of wear measured via the mass loss method (mg), S is the sliding distance of the specimen (m), and F is the loading force (N).
An experimental investigation on milling features of fully-sintered zirconia ceramics using PCD tools
Published in Materials and Manufacturing Processes, 2022
Jinyang Xu, Linfeng Li, Ming Chen, J. Paulo Davim
Zirconia is currently treated as a promising restorative bio-material in dental fields due to its unique properties and excellent biocompatibility.[1–9] To meet stringent dental application requirements, zirconia ceramics are often fabricated by adding a certain amount of yttrium oxide into the material base to stabilize the phase transformation and retain high strength and fracture toughness.[5,10] These zirconia-based materials are often named the yttria-stabilized tetragonal zirconia polycrystals (Y-TZP). They become very popular in modern restorative dental fields because of their high strength, high hardness, superior heat resistance, and excellent biocompatibility.[4,5,11] Among these materials, the 3 mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP) becomes the most preferred bio-ceramic in dental restorations.[12] The introduction of yttrium oxide aims to resist the stresses developed in the phase transformation, hinder the crack propagation and simultaneously retain the hardness.[8] Additionally, zirconia ceramics basically involve three possible allotropes, including the monoclinic phase maintained at room temperature, the tetragonal phase prepared at the complete sintering temperatures, and the cubic phase formed at 2370°C.[6,13] It is worth noting that these crystal phases can be transformed depending on the degree of the sintering temperature.