Metal porcelain teeth
Metal porcelain teeth are divided into ordinary porcelain, shoulder table porcelain, titanium alloy porcelain, gold-plated porcelain, and precious metal porcelain according to the materials and production processes used in the inner crown. Each has unique characteristics:
1. Golden inner crown.
That is, precious metal porcelain teeth. Its inner crown contains more than 84% gold, and contains platinum, palladium and other metals, which can not only reduce the weight of the restoration, but also strengthen its strength, and it is not only not prone to metal allergy, but also has a certain help for the decomposition and absorption of body proteins, and is the best in metal porcelain teeth. The price varies somewhat depending on the weight of the gold used, and the biocompatibility is excellent. Safe for oral mucosal tissue. The gum color of the neck has a natural warm color, which has a good aesthetic effect and a realistic shape. Unique gold color, porcelain color matching effect is very ideal, no damage to natural teeth. And because precious metals do not undergo chemical corrosion in the human environment, there are no toxic side effects on the human body, and there are no metal black lines on the gums.
2. Gold deposition.
The porcelain crown made by gold deposition technology shortens the process of turning the mold, resulting in less production errors and close contact with the real tooth. Due to the thin inner crown of metal, porcelain is more natural and beautiful, making it the preferred type of anterior dental restoration. Its characteristics are: no allergic reactions, beautiful and firm.
3. Nichrome alloy.
Its inner crown is cast from base metal nickel-chromium alloy, in the complex oral environment, the exposed metal part of the oral cavity will slowly decompose and release black oxides, resulting in local tissue staining, which is the most important reason why this restoration will cause black lines of the gums. The stability of porcelain teeth made of nickel-chromium alloy material is not good enough, easy to oxidize, not resistant to corrosion. Long-term immersion in oral saliva environment, nickel ions are easy to precipitate, although it is very safe, but individual patients will still have allergic reactions to nickel ions.
According to the current State Food and Drug Administration standards, nickel is the main component in nickel-chromium porcelain teeth, accounting for 69% to 77% of the weight ratio of the metal part; The weight ratio of chromium is between 13% and 16%. In addition, it also contains other metals such as molybdenum, which vary slightly by manufacturer. Nickel-chromium porcelain teeth are accepted by patients with low living standards but who need to install them because of their relatively low price. Due to the characteristics of the metal, the crown edge has a worse fit than other porcelain crowns.
4. Cobalt chromium inner crown.
Among them, the cobalt content will not exceed 30%, still need to add such as nickel to improve its plasticity, in fact, it belongs to nickel-chromium alloy, but the degree of hardness is higher than nickel-chromium, clinically mostly use greater than 630MPa medium hardness cobalt-chromium alloy, the root cause is not much different from ordinary porcelain (nickel-chromium porcelain), but the nickel content is reduced.
5. Titanium alloy.
Titanium alloy porcelain tooth is the inner crown is added to the titanium alloy by the ordinary metal crown, because titanium is more stable than nickel chromium, titanium alloy porcelain and human body compatibility is better than ordinary alloy porcelain, but not as good as precious metal porcelain. Its price is between ordinary alloy porcelain and precious metal porcelain.
6. Gold-plated inner crown.
Gold-plated inner crown porcelain teeth are based on nickel-chrome porcelain teeth, in order to solve the possible reaction problems of ordinary alloy porcelain, a layer of gold is plated on the surface of the metal inner crown. It is gilded on the part in contact with the tooth body and gums, and the outer layer is porcelain. Theoretically, the free nickel is controlled, which greatly reduces the possibility of metal allergy and gum black staining. Because of its moderate price, it is the best price alternative to titanium alloy porcelain.
7. Pure titanium inner crown.
Due to its excellent biological safety, light weight, stable chemical properties and high mechanical strength, titanium is an ideal metal in prosthodontic materials. However, due to its high melting point, easy oxidation, and the thermal expansion coefficient of pure titanium is lower than that of porcelain powder, the coefficient is too large, which means that the probability of porcelain collapse of pure titanium porcelain is higher than that of other types of porcelain.