When the cavity is not large, the treatment is very simple. It is only necessary to remove the blackened and decayed hard tissues of the tooth and then fill the cavity with composite resin. If the cavity of the tooth is large, the tooth has already appeared the symptom of transient sensitivity to hot and cold stimulation or even pain. In this case, the doctor will remove the decayed tissues and do indirect pulp capping treatment at the same time, i.e., after lining the bottom of the cavity with a layer of calcium hydroxide type of pulp protection medication, the cavity will be filled with composite resin. If the tooth is dark and the damage is extensive, it is possible that the tooth is a dead pulp tooth. For dead pulp teeth, root canal treatment should be done to remove the necrotic and infected pulp nerve, remove the source of infection, and fill the root canal tightly. The defect of the crown can be restored by simple resin filling, or by doing inlay restoration, or by using the method of wrapping all-ceramic or porcelain crowns.