Throughout your life, you will have two sets of teeth: primary (baby) teeth and secondary (permanent) teeth.
At birth the developing teeth are usually still embedded in the gums. For most infants, the front teeth begin to peek through the gums between four and eight months. Generally, children get four new teeth every month. The teeth begin to form when the infant is around six months old. By the time the baby reaches 12 to 15 months old, all of the primary teeth within the gums have formed crowns (the visible part of the tooth). Most children have all 20 baby teeth by 2 ½ to 3 years of age. Permanent teeth continue to develop within the jaw.
Baby teeth erupt in pairs on the right and left of the mouth, alternating between the lower and upper jaws, and proceeding from front to back. The 20 primary teeth usually erupt in the following order:
- 4 front teeth or central incisors, first in the lower jaw and then in the upper jaw
- 4 lateral incisors, on each side of the front teeth, uppers before lowers
- 4 first molars, uppers first
- 4 canines or cuspids, between the lateral incisors and the first molars, usually uppers before lowers
- 4 second molars behind the first molars, lowers first
Baby teeth may come in straight or at an angle and appear crooked, but they eventually straighten out.
Between 2 ½ and 6 years of age, the permanent teeth continue to develop within the jaw. The six-year-molars, the first permanent teeth, erupt behind each of the four second baby molars, usually between the ages of 5 and 6. By about age eight, enamel has formed on all of the permanent teeth except the wisdom teeth. A permanent tooth usually comes in about two months after the corresponding baby tooth is lost. Between the ages of about age 6 and 12 to 14, as the jaw grows, 28 permanent teeth erupt, replacing the primary teeth, incisor for incisor, canine for canine, premolar or bicuspid for molar. The 32 permanent teeth generally erupt in the following order:
- 4 six-year molars
- 4 central incisors or front teeth, first in the lower jaw and then in the upper jaw
- 4 lateral incisors, lowers usually first
- 4 canine teeth, lowers first
- 4 first premolars or bicuspids, between the canines and the six-year molars, uppers usually first
- 4 second premolars or bicuspids, between the first premolars and the six-year or first molars, uppers usually first
- 4 second molars, behind the first molars, lowers usually first
- 4 third molars or wisdom teeth at the back, usually between ages 17 and 21