The |teeth| are formally considered as accessory digestive organs, but as they are both osseous tissue as well as integral to the structure of the |skull|, they deserve to be treated with the skeletal system. The average adult human has 32 |teeth|, with 16 of these being anchored in the |maxilla| and 16 in the |mandible|. Chewing is accomplished by moving the |mandible| in proximity to the |maxilla| so that the |teeth| of the two bones are brought together, cutting, grinding, and tearing food. The |teeth| are paired, with two of each variety in the top row and two of each in the bottom, with every tooth in the top row matching one in the bottom as well. In the adult, the sixteen |teeth| in a row consist of four incisors (2 central, 2 lateral), two |canines|, four |premolars |(also called |bicuspids|), and six |molars |(also called |tricuspids|). In the child, however, the four premolars and the back two molars are missing in the deciduous (non-permanent) |teeth|. Because it is usually between the age of 18-21 that the last two molars grow in, these |teeth| are often called "wisdom |teeth|."
