Medical titanium alloy, as a new type of alloy and also a carrier material, is widely used in limb implantation, alternative functional materials, dentistry, medical devices and other related fields. Titanium and titanium alloys have the characteristics of good corrosion resistance, high specific strength, low elastic modulus, fatigue resistance, and good biocompatibility. The characteristic of good biocompatibility gives it a unique advantage compared to other metals, making it widely favored in the medical field. However, due to its low wear resistance and process performance, efforts to further improve it are also ongoing.

With the rapid development of the national economy, the demand for medical titanium alloys is constantly increasing in the medical field due to their excellent performance. As a metal material with excellent biological properties, titanium and its alloys have promising application prospects in the medical field. However, compared to developed countries, there is still a certain gap in the research and application of titanium alloy materials in China, such as the high elastic modulus, poor surface activity, and insufficient wear and corrosion resistance of titanium alloys, which will directly affect the biocompatibility of materials. Therefore, in order to develop new titanium alloys with better comprehensive performance, China should increase its research and development efforts in materials, focus on innovation, and develop biomedical titanium alloy materials with low elastic modulus, high wear resistance, corrosion resistance, and excellent biocompatibility.

Titanium has good affinity with human connective tissue and skeletal epithelial tissue, and its excellent mechanical properties also reflect its advantages in medical alloys. Due to its low density, light weight, good corrosion resistance, and comfortable wearing, titanium is widely favored as a denture (implant). In addition, after surface treatment, titanium dentures have increased aesthetic performance, which can meet the public's demand for beauty and provide visual enjoyment.

01. Used in the direction of medical devices

Medical titanium alloy medical instruments are the third generation surgical instruments after carbon steel and stainless steel. Stainless steel instruments often undergo surface treatments such as chrome plating and electropolishing to improve their rust resistance. But chromium is toxic, and the detached chromium layer can have a certain impact on the human body.

The benefits of using medical titanium alloy as medical devices are:

1. The instruments are lightweight and can reduce damage to blood vessels, muscles, and organs during the surgical process, reducing doctors' fatigue. Medical titanium instruments are more suitable for fine microsurgical operations;

2. Good corrosion resistance and non-toxic, equipment does not rust, wounds are not easily infected, and wounds heal quickly;

3. The elasticity of medical titanium alloy is moderate, suitable for making instruments such as forceps, forceps, and microsurgical knives;

4. When operating under a shadowless lamp, medical titanium has weaker reflective properties and is more suitable than stainless steel;

Medical titanium medical instruments mainly include surgical knives, surgical forceps, surgical forceps, chest expanders, suture needles, sutures, etc. Compared with other materials such as stainless steel wire, medical titanium wire used as surgical suture has the advantages of low tissue response and good torsion resistance. After suturing, the surgical wound is less prone to inflammation and the bone suture site is less prone to displacement. Sutures are generally made of medical titanium wire (TA1 or TA2 wire) with a diameter of 0.5-0.8mm. In addition, the soft elasticity produced by titanium nickel alloy wire can promote rapid wound healing.

In addition, medical titanium alloy is also an important material for auxiliary rehabilitation equipment, such as making wheelchairs, crutches, splints, medical instruments, etc.

02. Widely used as artificial joint materials

According to relevant literature reports, approximately 100 million patients worldwide suffer from inflammation related to the knee and arm joints every year, and replacement surgery is imperative. Therefore, titanium alloys with excellent replacement functions bring good news. Compared with materials such as ceramics and stainless steel, titanium alloy has an elastic modulus closer to that of human bones, and has more advantages in terms of modulus size. Therefore, titanium alloys have been widely used in the correction of ankle and elbow joints. In addition, porous titanium alloy materials can endow prostheses with biological activity, which helps to heal the femoral head; The biocompatibility of titanium alloy surface is good, which can induce bone cell growth, so it is highly praised by clinical doctors, orthopedic experts, and others.

The advantages of titanium and titanium alloys as implant restorations mainly include: ① high strength, good chemical stability, and biocompatibility; ② Non toxic and will not cause harm to the human body; ③ Low elastic modulus, more compatible with human bones; ④ Memory alloys have the elastic ability and shape recovery function. In summary, the application of titanium in skull repair is mainly reflected in the use of titanium mesh to repair damaged skull. The application in human cardiovascular system is reflected in the preparation of artificial heart valves, blood filters, pacemakers, and artificial heart pumps.

It should be noted that titanium is not suitable for all artificial joint parts. In the joint parts, the parts that frequently swing are not suitable due to titanium being prone to wear and tear (preferably using ceramics and cobalt alloys), and the implanted parts should use titanium alloys. In order to combine it with biological bone as soon as possible, the surface of titanium alloy needs to be roughened and coated with bone sensing materials such as apatite and bioglass.

03. Titanium has important help for dental development

The metal used in dental surgery began with amalgam and metal crowns in the 1920s. In the 1960s, gold, silver, and palladium alloys were mainly used. After the 1970s, stainless steel became the most commonly used material for permanent and removable dental instruments. In the 1990s, titanium casting technology was promoted and applied. The use of titanium precision casting machines in dentistry has the characteristics of high dimensional accuracy, no bubbles, and shrinkage cavities. Among metal materials used for human hard tissue repair, titanium has the closest elastic modulus to human tissue, which can reduce the mechanical incompatibility between metal implants and bone tissue. Titanium has the lowest thermal conductivity among all dental restorative metal materials, and low thermal conductivity can reduce thermal stimulation to the dental pulp of crown teeth, which is important for dental restoration. Titanium inlays, full crowns, etc. have the effect of protecting dental pulp and avoiding cold and hot stimulation. Dental titanium was originally mostly pure titanium in terms of material, but its strength is insufficient, difficult to grind, poor wear resistance, easy to produce casting defects, and unstable quality. Titanium alloy has high strength, and the most commonly used one is Ti-6Al-4V alloy. However, due to the harmful effect of metal V on human health, Nb was used instead of V, and Ti-6Al-7Nb alloy was successfully developed. It has excellent corrosion resistance, is basically harmless to human health, and has other advantages such as strong plasticity and excellent abrasiveness, which has been recognized by ASTM standards. At present, super elastic Ti Ni alloy is being promoted and applied in tooth straightening.

Since the 1980s, developed countries have been studying the application of titanium in oral restoration, first for dental implantation, and later for denture brackets, crowns and bridges, and dental alignment. Currently, titanium can be used as a crown, crown nail, fixed bridge, porcelain bridge, bonding bridge, denture clasp, base, connection device, and reinforcement device. Almost all metal components of dentures can be made of titanium. The research on titanium and titanium alloys has become a hot topic in the field of dental application alloys. Titanium alloy porcelain veneers can effectively restore tooth shape and function, with high strength, beautiful appearance, stable color, smooth surface, wear resistance, and corrosion resistance. They are a permanent restorative material suitable for all fixed teeth, especially those with good biocompatibility and sensitivity to nickel ions. They have been widely promoted and applied in dental restoration.