If the tooth is rotten and painful, the first thing you should do is to go to the professional dentistry department to check and treat the tooth, check the reason and degree of tooth rotten, in most cases, the tooth rotten and painful is caused by tooth decay, then you should check the degree of decay, if the degree of decay is light, you can consider applying the repair method to fill the cavity. If the decay has already penetrated into the pulp of the tooth, it is necessary to carry out root canal treatment for the tooth, and after the treatment, it is generally recommended to carry out crown restoration to protect the crown of the tooth, so that the tooth can serve the chewing function for a long time, but if the decay of the tooth is so serious that it has invaded the root of the tooth, sometimes the tooth cannot be preserved, it is necessary to extract the tooth directly and choose implant restoration or movable restoration. However, if the tooth is so badly decayed that the root can no longer be retained, it is necessary to extract the tooth and use implant restorations or removable restorations.