Eruption of teeth. With the elongation of the tooth root, the crown progressively rises above the bony alveolus and finally erupts through the oral mucous membrane. The part of the mucous membrane containing the crown is the gums (gingiva). Eruption of the milk teeth normally occurs between month 6 and 24 following birth. The permanent teeth begin to break through when the child is aged 6 years. However, the formation of teeth is only complete (i.e. when the wisdom teeth form) between 18 and 24 years of age.
Dental formula. Dentition is divided into four quadrants in the mouth. Five deciduous teeth (two incisors, one canine and two molars) form in each quadrant. They are then replaced by eight permanent teeth (two incisors, one canine, two premolars and three molars).