Children’s teeth begin forming before birth. Around six months, the first primary (or baby) teeth to erupt through the gums are the lower central incisors, followed closely by the upper central incisors. Although all 20 primary teeth usually appear by age three, the pace and order of their eruption varies.
Permanent teeth begin appearing around age six, starting with the first molars and lower central incisors. This process continues until approximately age 21.
Adults have 28 permanent teeth, or up to 32 including the third molars (or wisdom teeth).