The dentist opens the diseased tooth, removes the inflamed and necrotic pulp tissue inside the tooth with various instruments, disinfects and cleans the pulp chamber (including the wall of the pulp chamber), and finally seals the pulp chamber tightly with dental cement and other materials. Generally speaking, root canal treatment is suitable for pulpitis, pulp necrosis, and all types of periapical inflammation, including pulpitis caused by caries, crypt fracture, overconsumption, pulp penetration, etc. and pulp necrosis where the living pulp cannot be preserved. Many patients do not understand why it is necessary to do a full crown protection after root canal treatment, when the tooth does not hurt anymore and the filling can be done? In fact, this step is necessary for three main reasons: The reason for crowning1 Root canal treatment is to remove and disinfect as much debris and bacteria as possible from the root canal by means of medication and instrumentation. However, if this disinfection process is to be done carefully, a lot of bacteria-infected teeth must be removed, as well as tooth tissue that has to be trimmed. Therefore, most teeth that have undergone root canal treatment may not be strong enough to support chewing and may fracture, and it is impossible to restore function with the material alone, and even if you can, the long-term results are not good. Reason 2 After root canal treatment, the tooth loses its nutrient supply from the pulp, just like a tree that loses its roots, it slowly withers and becomes fragile, causing the tooth to become more brittle and prone to fracture. The reason for crown 3 is that the teeth that need root canal treatment are generally carious (worm teeth) and defective, at this time, although the root canal treatment is completed, the remaining tooth tissue is very fragile, very easy to fracture, crack, and lose the normal function, and it is impossible to restore the function simply with the material. Crown material ordinary cheap – nickel-chromium alloy nickel-chromium alloy material, cheaper, in Europe and the United States belongs to the elimination of technology, the long-term use of metal crowns will produce nickel element precipitation, 15% of users have mild toxic reactions and allergies to the aggregation of metal gum blackening. Affordable – cobalt-chromium alloy The representative of semi-precious metal crown is cobalt-chromium alloy crown, called “nickel-free beryllium-free alloy”. The main components are cobalt and chromium, which are priced between non-precious metals and precious metals, and are more biocompatible than nickel-chromium crowns, resistant to corrosion and less likely to chip, avoiding bleeding gums and black gums. And economic, practical, suitable for most dental restorations, especially for fixed restorations such as fixed bridges for posterior teeth. Star-like teeth – all-porcelain crowns The color of all-porcelain crowns can maintain the natural color no matter under the light and natural light, so it has become the current favorite of film and television stars and public figures of dental beauty. All-porcelain crowns have good permeability and color, excellent aesthetic effect, good biocompatibility, and are harmless to human body. All-porcelain teeth are divided into two categories according to the material alumina and zirconia, both have very good biocompatibility, better durability, can be permanently preserved in the mouth; because there is no metal base, all-porcelain teeth are lighter, more comfortable to wear, but also more conducive to protecting the health of the pulp; reflection and scattering of light closer to natural teeth, so there is a better aesthetic effect.