In humans, there are usually 20 primary (baby) teeth and 28 to 32 permanent teeth, the last four being third molars or wisdom teeth, each of which may or may not grow in. Among primary teeth, 10 usually are found in the maxilla (upper jaw) and the other 10 in the mandible (lower jaw). Among permanent teeth, 16 are found in the maxilla and the other 16 in the mandible. Most of the teeth have distinguishing features.