At age 21, most grown adults have their new complete set of teeth, made up by 32 pieces, including:
8 incisors 4 canines or cuspids. 8 premolars or bicuspids. 12 molars. These also include wisdom teeth.
Teeth have several layers with different functions and characteristics. The first one being the enamel, which is the white, external and visible part of the tooth. Underneath, there is a layer of strong tissue called the dentin, where microscopic tubes are located. When damaged, the enamel can produce sensitivity or pain inside the tubes of the dentin. The other three layers are the pulp, the cementum, and the periodontal ligament.