With proper maintenance, all teeth last a lifetime, so at age 70 it is normal to have intact dentition, i.e. no missing teeth except for unerupted wisdom teeth. 1. Under normal circumstances, adults have a total of 28 teeth, after the age of 18 may grow wisdom teeth, that is, the third molar, and after the age of teeth will gradually fall out, the number of teeth will gradually decrease, which is often due to periodontal disease, in the case of good periodontal control can be avoided tooth loss. 2. If the elderly usually pay more attention to periodontal maintenance, often eat soft, not hard food, periodontal condition is relatively good, the degree of wear and tear of the teeth is relatively light, the amount of tooth loss is relatively small; if you do not pay attention to periodontal maintenance, and often chew hard food, it will lead to increased wear and tear of the teeth, easy to increase the amount of tooth loss. If an elderly person’s normal chewing is affected by tooth loss, he or she can directly get fillings or wear dentures. For those who are in need can consult the doctor first and follow the doctor’s advice.