Zirconia implants: characteristics, applications and preparation process
The introduction of zirconia implants is an important breakthrough in the biomedical field. As early as the 1970s, zirconia materials began to be used in the field of dental restorations to manufacture artificial teeth and crowns.
Entering the 21st century, with the advancement of materials science and manufacturing technology, the application scope of zirconia materials has continued to expand. In the field of orthopedics, zirconia is used to manufacture artificial joints and fracture fixation devices. Its superior mechanical properties and biocompatibility make it an ideal substitute for traditional metal materials. This article will introduce in detail the characteristics, applications, preparation processes and future development trends of zirconia implants.
1.Characteristics of zirconia implants
(1) Superior mechanical properties
Zirconium oxide has high hardness, high strength and good toughness, which makes it perform well when subjected to large mechanical stress. Taking dental implants as an example, zirconia implants can not only provide sufficient support, but also effectively prevent implant breakage or wear, thereby extending the service life. Studies have shown that the five-year success rate of zirconia implants is as high as over 98%, which is significantly better than some traditional materials.
(2) Good biocompatibility
Zirconium oxide is a biologically inert material with good compatibility with human tissues and will not cause obvious immune or inflammatory reactions. After implantation, a stable oxide layer can be formed on the surface of zirconium oxide, which effectively prevents corrosion and degradation and ensures long-term stability. In addition, zirconium oxide does not contain metal components, avoiding the potential health risks caused by the release of metal ions.
(3) Excellent aesthetic effect
Zirconium oxide has a color and transparency similar to natural teeth, and can provide a more natural and beautiful restoration effect. In the aesthetic area of the anterior teeth, zirconium oxide implant restorations can almost achieve a real-life effect, meeting the patient’s high requirements for beauty. At the same time, zirconium oxide materials have good refraction and scattering properties for light, making the restoration more realistic.
(4) Strong corrosion resistance
Zirconium oxide exhibits good corrosion resistance in various physiological environments and will not degrade or release harmful substances due to the effects of body fluids, enzymes, etc. This not only ensures the long-term stability and safety of the implant, but also effectively avoids complications caused by material corrosion.
2.Application of zirconia implants
(1) Dentistry
Zirconium oxide is most widely used in the dental field, mainly as implants and all-ceramic crown and bridge materials. Compared with traditional metal implants, zirconia implants have better biocompatibility and aesthetic effects, especially suitable for the anterior teeth and patients with high aesthetic requirements. In addition, zirconia all-ceramic crown and bridge materials have excellent mechanical properties and aesthetic effects, and can provide more natural, beautiful and durable restorations.
(2) Orthopedics
In the orthopedics field, zirconia is mainly used as joint replacement materials and bone fixation materials. Zirconia joint replacement materials have excellent wear resistance and biocompatibility, which can effectively reduce wear and inflammatory response and improve the long-term success rate of joint replacement. In addition, zirconia bone fixation materials have sufficient strength and good biocompatibility, which can provide stable fixation support for fracture healing.
(3) Other fields
In addition to dentistry and orthopedics, zirconia implants are also used in plastic surgery, otolaryngology and other fields. For example, in plastic surgery, zirconium oxide can be used to make artificial skulls, artificial jaws and other implants; in otolaryngology, zirconium oxide can be used to make artificial ossicles and other implants.
3.Preparation process of zirconium oxide implants
Zirconium oxide implants are widely used in the medical field due to their excellent mechanical properties, biocompatibility and corrosion resistance, such as artificial joints and dental implants. The following are the main preparation processes of zirconium oxide implants:
(1) Raw material preparation
The preparation of zirconium oxide powder is generally divided into physical and chemical methods. Physical methods include mechanical grinding, solid phase method, etc.; chemical methods include wet chemical methods (such as precipitation method, hydrothermal method), solvent evaporation method, etc.
Among them, co-precipitation method and hydrothermal method are more commonly used. The co-precipitation method is to mix zirconium salt with stabilizer and then add precipitant to generate water-insoluble hydroxide, which is then heated and decomposed to obtain high-purity ultrafine powder. The hydrothermal method is to carry out chemical reaction in aqueous solution under high temperature and pressure to directly generate nano-scale zirconium oxide particles.
(2) Molding process
The prepared zirconia powder is made into a green body of the desired shape by dry pressing, slip injection, cold isostatic pressing and other methods. Dry pressing is suitable for products with simple shapes, slip injection is suitable for products with complex shapes, and cold isostatic pressing can improve the density and uniformity of the green body.
The green body after molding needs to be debinded to remove organic additives in the green body and prevent bubbles and cracks from being generated during sintering.
(3) Sintering process
The green body after debinding is sintered at high temperature to make it dense. The sintering temperature is generally between 1400 and 1600°C, and the sintering time depends on the size and thickness of the green body. During the sintering process, the heating rate and cooling rate need to be controlled to prevent cracking and deformation of the green body.
In order to improve the toughness and strength of zirconia implants, stabilizers (such as yttrium oxide, magnesium oxide, etc.) are usually added to form partially stable tetragonal zirconia (t-ZrO2).
(4) Post-processing process
Post-processing process mainly includes mechanical processing, surface treatment and disinfection and sterilization. Mechanical processing is used to fine-tune the shape and size of sintered zirconia implants. Commonly used mechanical processing methods include turning, milling, grinding, etc. to meet the requirements of clinical applications.
Surface treatment is used to improve the surface properties of implants, such as increasing surface roughness and promoting bone integration. Disinfection and sterilization are used to ensure the sterility of implants and ensure the safety of clinical applications.
(5) Micro-arc oxidation technology
Micro-arc oxidation technology is an important means of surface modification of zirconia implants. This technology generates micro-arc discharge on the surface of zirconia by applying high voltage in the electrolyte to form a dense and porous oxide film.
The specific process is: the sintered zirconia implant is used as the anode and placed in the electrolyte. The thickness and structure of the oxide film are controlled by adjusting the voltage, current density, electrolyte composition and reaction time. Micro-arc oxidation technology can significantly improve the surface hardness, wear resistance and bioactivity of the implant.
4.Future development trend of zirconia implants
(1) Improvement of material properties
Although zirconia materials already have good properties, there are still areas that need to be improved in terms of their brittleness. For example, by adding other elements or adopting new preparation processes, the strength, toughness and biocompatibility of zirconia can be further improved.
(2) Application of digital technology
With the continuous development of digital technology, the combination of zirconia implants and digital technology will be closer. Through 3D printing technology, more complex and personalized zirconia implants can be manufactured to meet clinical needs. In addition, digital technology can also be used for preoperative planning and simulation to improve the accuracy and success rate of surgery.
(3) New application fields
In addition to oral implants, orthopedic repair and plastic surgery, zirconia materials are expected to be used in more fields. For example, in the cardiovascular field, zirconia materials can be used to manufacture implants such as artificial heart valves; in the ophthalmology field, zirconia materials can be used to manufacture artificial lenses, etc.
(4) Cost control
Although zirconia implants have many advantages, their cost is relatively high, which to a certain extent limits their promotion and application. In the future, with the improvement of production technology and the realization of large-scale production, the cost of zirconia implants is expected to be further reduced, so that they can benefit more patients.
5.Conclusion
Zirconium oxide implants have shown broad application prospects in the medical industry with their excellent performance and biocompatibility. With the improvement of material properties, the application of digital technology and the expansion of new application fields, zirconia implants will continue to play an important role in the future, bringing better treatment effects and quality of life to patients.