Toothache after biting something hard is mostly transient and can be relieved on its own. If the symptoms do not improve, it may be related to tooth decay, fissure, periodontitis and so on. It is recommended to go to the hospital in time to clarify the cause of the problem. Toothache after biting hard things is a common phenomenon, the food is too hard to cause the nerve of the teeth appear transient pain, usually can be relieved on their own. If the symptoms have not been improved may be related to the following diseases. 1. Tooth decay: also known as caries. Teeth are damaged by bacteria, resulting in tooth pain after biting something hard. Usually there is a cavity in the tooth. Amalgam filling, bonding restoration, inlay restoration, etc. are required. 2. Cracked tooth: After biting something hard, the tooth is pressurized and cracked, which will lead to tooth pain. Surgery is needed to fill, bond or fix the crack in the affected tooth, and crown restoration can be done if necessary. 3. Periodontitis: If the patient himself has periodontal inflammation, after biting something hard, it will stimulate the tooth pain. Acetaminophen and ibuprofen can be used to relieve the pain. In severe cases, periodontal flap surgery, soft tissue transplantation, bone grafting and other surgical treatments are needed. 4. Periapical periodontitis: Periapical periodontitis is caused by an infection in the pulp that enters the root tip, which can produce biting pain, floating sensation, etc. Root canal therapy is needed for treatment. If the toothache after biting hard things has not been improved or aggravated symptoms, it is recommended to go to the hospital in time, to clarify the cause of treatment, the use of drugs need to follow the doctor’s instructions.