Patients with periodontitis may suffer from chronic periodontitis, in which multiple teeth in the mouth are accompanied by a disproportionate amount of alveolar bone resorption, causing the alveolar bone to become low and the gums to recede, gradually exposing the roots of the teeth in the mouth and causing the teeth to gradually loosen as the condition worsens. In patients with chronic periodontitis, the teeth are unable to withstand excessive occlusal stress, which can cause pain once hard food is eaten. In addition, if you eat cold, hot, sour, sweet and other irritating foods, it will also cause the teeth to become sensitive, resulting in soreness and even pain. If the fracture of individual teeth is deeper and reaches the deeper layer of dentin or even the pulp cavity, the tooth will experience severe pain after biting into hard objects.