Large teeth are mainly referred to as molar teeth in clinical practice. The loosening of molar teeth may be related to malnutrition, lack of calcium in the body, external impact and other factors. Patients can try to supplement milk, soy products, dried fruit and other foods with high calcium content, and persist for a few days to observe whether the pain is relieved. If the symptoms of loose and painful grinding teeth are not relieved for a long time, or when obvious swelling and pain and bleeding occur in the affected area periodontally, it may also be caused by tooth degradation, etc. 1, tooth degradation: with age, or congenital underdevelopment of teeth, long-term chewing of soft food, will generally accelerate the degradation of teeth, resulting in loose and painful grinding teeth, and some serious patients may also experience grinding tooth loss; 2. Tooth decay: excessive intake of sweets, improper oral cleaning and other reasons will lead to the formation of tooth decay. When the damage area of tooth decay is large or the lesion involves the root of the molar, it will induce loosening and pain of the molar. Symptoms may worsen when patients with tooth decay eat irritating foods such as cold and acid. Since tooth decay is a progressive disease, it is recommended to go to the hospital dentistry department for treatment as soon as possible; 3, periapical periodontitis: when the loose grinding teeth are accompanied by symptoms such as biting pain, swollen gums and pus, it is considered to be bacterial infection inside the pulp cavity, thus causing periapical periodontitis; 4, periodontitis: plaque, tartar and traumatic bite may lead to the occurrence of periodontitis. When the alveolar bone resorption is involved to the molar area, patients mostly show symptoms such as loose molar teeth, pain, red and swollen gums, periodontal bleeding and bad breath.