Adults have a full mouth of 32 teeth and children have a full mouth of 20 teeth before tooth replacement, but the number may change due to congenital and acquired factors. Adults have a full mouth of 32 teeth, which are symmetrical between the upper and lower parts of the mouth, with 8 incisors and 8 lateral incisors, 4 cuspids, 8 premolars, and 12 molars. Children have a total of 8 milk incisors and milk lateral incisors, 4 milk cusps, and 8 milk molars. In adults, the number of third molars (wisdom teeth) varies greatly depending on genes and acquired factors, and may be congenitally missing, in which case the number of teeth in the mouth will be less than 32, and there may be multiple teeth due to a variety of factors. The number of teeth in a person’s mouth has individual differences and varies greatly, and the exact number varies from person to person. The exact number of teeth varies from person to person and can be determined by taking a radiograph at the hospital.