The tooth is bad half rotten is due to bacterial progressive destruction, resulting in tooth erosion, when the dentin and enamel of the tooth will form a disintegrated cavity. This kind of cavity is brownish-black decayed material, need to go to the stomatology department to remove the decayed material and then fill the tooth, restore the shape of the tooth in order to chew normally, and also to avoid the injury to the nerve or the tooth is completely split. If the nerve of the tooth is damaged, a root canal will be needed. After the nerve is removed, the tooth will need to be restored with a dental brace, also known as a porcelain crown. If the tooth bites into the split area, the tooth will need to be extracted and treated with an implant denture. Implant dentures are more expensive and have a longer waiting period.