With the development of society and the improvement of living standards, people's requirements for the aesthetics and function of teeth continue to increase. With the continuous development of dental restoration technology, the types of dental restoration materials are constantly being updated. At present, Zirconia Ceramic Rods there are three types of oral restorative materials commonly used in clinical practice: metal, composite resin and ceramic materials. Metal materials have the characteristics of high strength, good adhesion, wear resistance, and relatively less tooth tissue to be cut, but the aesthetics are poor. The composite resin material has strong plasticity, light weight, corrosion resistance and beautiful appearance, but the mechanical strength of the material is poor. Compared with traditional metal-porcelain crowns, all-ceramic crowns are superior in strength, hardness, aesthetic properties, corrosion resistance, fatigue resistance and biocompatibility, and are lighter in weight. All-ceramic crowns not only have light transmittance, but also Its mechanical properties are also similar to dentin. Ceramics have been used as oral restorative Zirconia Ceramic Tube materials for more than 200 years. Ceramic materials have the characteristics of good aesthetics, high mechanical strength (hardness, wear resistance, compressive strength, flexural strength), high stability, and strong permeability. It is more commonly used in prosthodontics.
Classification of all-ceramic materials
Some researcher Kelly divides all-ceramic materials into three categories according to the difference in the content of glass phase and crystal phase in the microstructure of the material:
(1) Feldspar porcelain is mainly glass phase, which is made of natural feldspar, quartz and kaolin three components by high temperature sintering. Feldspar is the earliest ceramic material used in dentistry, and its optical properties are very close to enamel and dentin. However, due to its poor mechanical properties, the flexural strength is usually only 60-70 MPa, so it is often used as a porcelain-fused-to-metal restoration and a fused-to-ceramic restoration.
(2) Glass ceramics contain both glass phase and crystal phase, also known as glass-ceramic, which is a kind of composite material combining crystal phase and glass made by high temperature melting, molding and heat treatment. Compared with amorphous glass, the addition or growth of crystalline fillers in the glass phase makes glass-based ceramics have great changes in mechanical and optical properties, such as increasing the thermal expansion coefficient and toughness, changing the color, opalescence of the material. sex and transparency. Zirconia Ceramic Ring Polycrystalline ceramic is a kind of dense ceramic material directly sintered from crystals without glass phase and gas phase. It has high strength and hardness and is processed by CAD/CAM equipment. Due to the lack of vitreous phase, these materials usually have low transparency and need to be decorated with veneer porcelain.
Glass-ceramics dominated by vitreous phase have good aesthetic properties, and as the number of crystals increases, their strength becomes higher and higher, but the transparency becomes poor. This classification method implies the relationship between ceramic components and indications. However, with the current development of polycrystalline ceramic microstructures, the advent of more and more translucent zirconia and stronger glass ceramics with reduced transparency has challenged this concept. Fundamental development of ceramic technology in industry: The manufacturing process of these materials has shifted from natural ingredients (i.e. feldspar) to synthetic ceramics. In 2015, Gracis et al. proposed a new classification method, and each classification is divided into different subgroups according to its composition.
In the "Expert Consensus on Clinical Application of All-Ceramic Aesthetic Restorative Materials" published by the Oral Aesthetics Professional Committee of the Chinese Stomatological Association in 2019, all-ceramic materials are classified according to their chemical composition and microstructure, and all-ceramic materials are divided into the following three categories : glass-matrix ceramics, polycrystalline ceramics and resin-matrix ceramics. Compared with traditional ceramic materials, resin-based ceramic materials have special properties due to the inclusion of organic scaffolds. It has the following advantages: ① It is closer to the elastic modulus of dentin; ② It reduces the brittleness and hardness of the material, making it easier to cut; ③It is more convenient to use resin for repair; ④It does not affect the strength after adjustment, and the clinical operation is simple; ⑤The abrasion of natural teeth is much less than that of glass ceramics; ⑥It does not require thermal processing, and its design and production can be completed by the chair.
Zirconia was first discovered as a mineral in 1892. After that, it was gradually understood and applied in various fields. Due to its high melting point of 2715°C, it has been widely used as a refractory material, such as the outer wall of the space shuttle. Since the 1960s, zirconia has been used in the medical field. With the progress of research on zirconia material structure and processing methods, the performance of zirconia has gradually improved, and its clinical applications have become more extensive, such as artificial hip joints and dental prostheses that we are more familiar with.
Application of zirconia ceramics in oral cavity
2022 07/20