The metals 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 instruments for orthodontics. In the 1990s, titanium casting technology was popularized and applied. Dental casting with titanium precision casting machine has the characteristics of high dimensional accuracy, no bubble and shrinkage hole. Among the metal materials used for human hard tissue repair, the elastic modulus of titanium is closest to that of human tissue, which can reduce the mechanical incompatibility between metal implant and bone tissue. The thermal conductivity of titanium is the lowest among all dental restoration metal materials. Low thermal conductivity can reduce the thermal stimulation to the dental pulp of crown teeth, which is important for tooth restoration. Titanium inlay and full crown can protect dental pulp and avoid cold and hot stimulation. As for the material of dental titanium, it was mostly pure titanium, but its strength was insufficient, it was difficult to grind, it had poor wear resistance, and it was easy to produce casting defects and unstable quality. Titanium alloy has high strength, and the most commonly used is Ti-6A-4V alloy, but because metal V is harmful to human body by replacing V with Nb, ti-6a-7nb alloy has been successfully developed. It has excellent corrosion resistance, is basically harmless to human body, and has other advantages such as strong plasticity and excellent abrasiveness. It has been recognized by ASTM standards. At present, hyperelastic Ti Ni alloy is being widely used in tooth straightening.
Since the 1980s, developed countries have begun to study the application of titanium in oral restoration, first for dental implants, and then for denture brackets, crowns, bridges and orthodontic wires. At present, titanium can be used as crowns, crown nails, fixed bridges, porcelain fused to metal bridges, bonding bridges, denture clasps, bases, connecting devices and reinforcing devices. Almost all metal parts of dentures can be made of titanium. The research of titanium and titanium alloys has become a hot spot in the research of dental applied alloys. Titanium alloy porcelain fused to metal teeth can restore the shape and function of the teeth well, with high strength, beautiful appearance, stable color, smooth surface, abrasion resistance and corrosion resistance. It is a permanent restoration and suitable for Cutting fixation teeth, especially its biocompatibility, are suitable for people who are sensitive to nickel ions, and have been widely used in tooth restoration.
