A toothache when you eat hard things may be caused by hidden cracks, periodontal disease, apical periodontitis, etc. It is recommended to go to the stomatology department for timely examination and treatment. 1. Frequent chewing of hard food may cause dental cracks, that is, there are small cracks in the teeth, and when it reaches a certain level, the teeth will stimulate the cracks to deepen and conduct to the nerves to experience pain when biting hard. 2. The calculus around the teeth will lead to alveolar bone resorption, the teeth will produce the phenomenon of loosening, when biting hard objects, the teeth will loosen to stimulate periodontal pain. 3. Periapical periodontitis is inflammation at the root tip of the tooth, when biting hard objects will press the pus or granuloma at the root tip to produce pain. If you eat hard things toothache should go to the regular hospital in time.