Titanium appearance with silver-grey lustre
Medical titanium alloy, as a new 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: good corrosion resistance, high specific strength, low modulus of elasticity, fatigue resistance, good biocompatibility and other characteristics. Among them, the feature of good biocompatibility gives it a unique advantage over other metals, so it has gained wide popularity in the medical field, but due to its wear resistance and process performance is not high, and is committed to its further improvement work is also in progress.
Titanium has a good affinity with the connective tissues of the human body and the epithelial tissues of the skeleton, and its excellent mechanical properties also reflect its advantages in medical alloys. Titanium has a low density, light weight, good corrosion resistance, and is comfortable to wear; therefore, titanium is widely used as a dental prosthesis (dental implants). In addition, titanium denture through the surface treatment, the aesthetic properties increase, can meet the public demand for beauty, giving people visual enjoyment.
01 for medical devices
Medical titanium alloy medical instruments are the third generation of surgical instruments after carbon steel and stainless steel. Stainless steel instruments in order to improve rust resistance, often after chrome plating, electropolishing and other surface treatment. However, chromium is toxic, and the shedding of the chromium layer will have a certain impact on the human body.
The benefits of medical titanium for medical devices are:
1. the instruments are lightweight, the surgical process can reduce the damage to blood vessels, muscles, organs, reduce the doctor’s fatigue, medical titanium instruments are more suitable for doing fine microsurgery.
2. good corrosion resistance and non-toxic, the equipment does not rust, the wound is not easy to be infected, wound healing fast.
3. Medical titanium alloy has moderate elasticity and is suitable for instruments such as pliers, forceps and microscopic scalpels.
4. when operating under a shadowless lamp, medical titanium has weaker reflective properties than stainless steel.
Medical titanium medical devices mainly include: scalpels, surgical forceps, surgical tweezers, chest expanders, suture needles and sutures. Medical titanium wire used as surgical sutures, compared with other materials (such as stainless steel wire), has the advantages of small tissue reaction and good anti-twist performance. After suturing, the surgical wound is not easy to be inflamed and the bone suture site is not easy to be displaced. 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 that the titanium-nickel alloy wire can produce can promote rapid wound healing. In addition, medical titanium alloy is also an important material for auxiliary rehabilitation devices, such as wheelchairs, crutches, splints, medical instruments and so on.
02 Widely used in artificial joint materials
According to the literature, about 100 million patients in the world suffer from inflammation of the knee and arm joints every year, and replacement surgery is a must, so titanium alloys with excellent replacement functions are a boon for this purpose. Compared with ceramics and stainless steel, titanium alloys have a modulus of elasticity that is closer to that of human bones, giving them an advantage in terms of modulus size. Therefore, titanium alloys are widely used in the correction of ankle and elbow joints. In addition, the porous titanium alloy material can make the prosthesis biologically active, which can help the healing of the femoral head; the surface of titanium alloy is more biocompatible, which can induce the growth of bone cells, so it is respected by clinicians and experts in the field of orthopaedics.
The advantages of titanium and titanium alloys as implantable restorations mainly include: ① high strength, good chemical stability and biocompatibility; ② non-toxic, will not cause harm to the human body; ③ low modulus of elasticity, more compatible with the human skeleton; ④ memory alloy with the elasticity of the ability to restore the shape and function. In summary, the application of titanium in cranial bone repair is mainly reflected in the following: the use of titanium mesh can repair the defective cranium. In the human cardiovascular application is reflected in: the preparation of artificial heart valves, blood filters, pacemakers and artificial heart pumps.
It is important to note that titanium is not suitable for all artificial joint parts. In the joint parts that swing a lot, titanium is not suitable because it wears out easily (ceramics and cobalt alloys are preferred), and titanium alloys are used for implanted parts. The surface of the titanium alloy is unevened and coated with apatite or bioglass as a bone-sensitive material in order to make it bond with the bone of the living organism.
03 Titanium is an important contribution to the development of dentistry
The metals used in dental surgery started with amalgam and metal crowns in the 1920s, gold, silver and palladium alloys were mainly used in the 1960s, stainless steel became the most commonly used material for permanent and removable instruments for orthodontics after the 1970s, and titanium casting technology was popularised in the 1990s. Dental use of titanium casting machine casting has high dimensional accuracy, no bubbles and shrinkage, etc. In the metal materials used for human hard tissue restoration, titanium’s modulus of elasticity is closest to that of human tissue, which can reduce the mechanical maladjustment between the metal implant and the bone tissue. The thermal conductivity of titanium is the lowest among all metal materials used for dental restoration, and the low thermal conductivity can reduce the thermal irritation to the dental pulp of teeth with crowns, which is important for dental restoration. Titanium inlays, full crowns, etc. have the effect of protecting the dental pulp from hot and cold irritation. Dental titanium in the material, the original mostly pure titanium, but its strength is insufficient, difficult to grind, there are poor wear resistance, easy to produce casting defects and quality instability and other characteristics. Titanium alloy strength is higher, the most commonly used is Ti-6Al -4V alloy, but because of the metal V is harmful to the human body, instead of using Nb V, the development of successful Ti-6Al-7Nb alloy, which has excellent corrosion resistance, and basically harmless to the human body, but also has a strong plasticity, excellent abrasive, and other advantages, has been recognised by the ASTM standard. At present, super-elastic Ti-Ni alloy is being promoted for tooth straightening.
The use of titanium in restorative dentistry has been investigated since the 1980s. First used for dental implants, and later used for denture brackets, crowns and bridges and dental orthodontic filaments, titanium can be used for crowns, crowns and nails, fixed bridges, ceramic bridges, bonded bridges, denture rings, base brackets, connecting devices and strengthen the device, almost all the metal parts of the denture can be made of titanium. The study of titanium and titanium alloy has become a hot spot in the study of alloys for dental applications. Titanium alloy porcelain teeth can well restore the form and function of the teeth, and high strength, beautiful appearance, stable colour, smooth surface, wear-resistant, corrosion-resistant, is a permanent restoration for all fixed teeth, especially its biocompatibility is good, nickel ion sensitivity is more suitable for people, is now widely promoted in the restoration of teeth.
