If half of the teeth have been lost, different treatments are needed according to whether the teeth have retention value or not. Generally, root canal treatment can be followed by crown restoration, and in serious cases, the teeth can be extracted and then restored with crowns and bridges or implant restorations. 1. With retention value: groove teeth, including the first molar to the third molar, if the first molar and the second molar lost half, you can go to the hospital stomatology department to take pictures to check whether the remaining half of the root of the tooth with or without retention value, to determine the retention of the tooth can be carried out after the root canal treatment, and then staking + porcelain crowns or all-ceramic crowns restoration. 2. No retention value: If the apical inflammation of the first or second molar is determined to be too large, root fracture, and the remaining root of the tooth is short and small, you need to consider extracting the tooth, and then wait for 3 months to carry out porcelain crowns and bridges or dental implants for restoration; in addition, if the groove tooth is a wisdom tooth, and there is a loss of half of the tooth, it is recommended that the tooth is best to remove all of the affected teeth.