The most important clinical symptom of occluded fissure is the presence of fixed-point occlusal pain. In mild cases, there may be no pain from hot or cold stimulation, a history of injury from biting hard objects, and examination may reveal an occluded fissure line. If there is only fixed biting pain without hot or cold irritation, the fracture line is usually confined to the superficial layer of dentin. For conservative treatment, a cavity can be prepared to eliminate the fissure and then resin filled and the over-steepened cusps can be resharpened. If the filling does not eliminate the symptoms, a crown can be restored and a temporary crown can be worn for an observation period of no less than 1 month. If there are symptoms of spontaneous severe pain during this period, the patient will be reviewed at any time for pulpotomy and root canal treatment. If the fixed-point biting pain is accompanied by hot and cold stimulation pain, it indicates that the cracked line reaches the deep dentin layer or even the pulp, and if the crown is made directly, the chance of transforming into pulpitis is very high. Therefore, the current treatment method is to make a temporary crown under local anesthesia to protect the affected tooth from longitudinal fracture, and to open the pulp to seal the pulp-killing medicine, and to do root canal treatment after two weeks, and to make the final crown restoration after completing the root canal treatment. If there is spontaneous pain, it proves that pulpitis has developed and only root canal treatment can be done before crowning. The tooth should be sharpened during the root canal treatment to prevent the tooth from biting and cracking open during the treatment, because if the tooth is completely cracked, the only way is to extract it. Patient: Description of the condition (time of onset, main symptoms, hospital visited, etc.): On December 22 of this year, I bit into a broken bone chip without paying attention. No treatment has been performed yet. A dental pulp is done on the cracked tooth to keep the diseased tooth.