Nerve extraction, the technical term for this is root canal therapy. Specifically, the physician opens the diseased pulp cavity, removes the inflamed, necrotic pulp tissue within it with various instruments, sterilizes and cleans out the pulp cavity (including the walls of the cavity), and then finally seals the cavity tightly with something such as an adhesive dental needle. The tooth after root canal treatment must be observed for about a week to make sure that it is symptom-free before subsequent treatment is carried out. Filling the cavity directly with a filling material is easy and convenient, but not sustainable. Because the teeth after root canal treatment, the teeth are generally left with an empty shell around the layer, and due to the loss of nutrient supply from the pulp, making the teeth themselves become more brittle and easy to break, and the back teeth in chewing may bear to 50 to 70 kilograms of force, the teeth in use at any time to face the risk of splintering, so the doctor will usually recommend that the teeth after the root canal treatment to do the braces to protect it. A few teeth if the defect is too large, if you directly do braces, it is very poor resistance to fracture, usually need to be in the root of the tooth to play a stake, make a strong nucleus, in order to fight against the tooth in use in the fracture force. Many patients because of a fluke, that do not eat hard things will not split, but clinically we will see a lot of cases because of the lack of braces and split, and finally had to be extracted, feel very sorry, so we recommend that it is still perfect and thoroughly do the braces to protect it is the first choice.