Children's teeth begin forming before birth. As early as 4 months, the first primary (or baby) teeth may erupt through the gums. Tooth eruption generally starts with the lower central incisors followed closely by the upper central incisors. Normally all 20 primary teeth appear by age 3, however, the pace and order of tooth eruption may vary.
Permanent teeth begin appearing around the age of 6, starting with the first molars and lower central incisors. This process continues until approximately the age of 21.
Adults have 28 permanent teeth or up to 32 including the third molars, also known as wisdom teeth.
