A decayed tooth does not necessarily need to be extracted, most of the decayed teeth can be retained through repair or root canal treatment, and there is no need to extract the tooth at all. If it is early shallow caries or medium caries, this kind of caries has not caused the symptoms of pulp at all, and the tooth is not painful yet. At this time, the decayed and decayed part of the caries can be removed by dental high-speed turbine drill, and then the cavity can be filled with special filling material. Even if the carious tooth has the symptom of pulpitis and there is obvious spontaneous pain and severe pain, the tooth can be protected by root canal treatment by killing the nerve and filling the root canal directly.