children s health issues
Physical Growth of Infants and Children
Teeth
The timing of tooth eruption varies, mainly for hereditary reasons. However, tooth eruption may also be delayed by disorders such as Hypophosphatemic Rickets , Lower front teeth usually begin to appear by the age of 5 to 9 months. Upper front teeth usually begin to appear by 8 to 12 months. On average, infants have 6 teeth by age 12 months, 12 teeth by 18 months, 16 teeth by 2 years, and all 20 of their baby (deciduous) teeth by 2½ years. Baby teeth are replaced by permanent (adult) teeth between the ages of 5 years and 13 years. Permanent teeth tend to appear earlier in girls. The symptoms caused by tooth eruption (such as drooling and fussiness) are called Teething . 