A baby is usually born with no visible teeth in their mouth. However, in a newborn baby, there are 20 fully formed milk teeth or primary teeth lying underneath the gums. These teeth are also known of as deciduous teeth since they loosen and fall out between the ages of 6 to 10 years to give way to the adult teeth that last on a more permanent basis.
The primary teeth emerge through the baby's gums during the initial couple of years of life. By the time the infant is aged 2.5 to 3.0 years, all 20 of the milk teeth have usually fully emerged. The milk teeth usually emerge in the following sequence:
- The four front teeth, the central incisors, are the first teeth to emerge (two in each of the upper and lower jaw) and start to appear as early as six months after birth. Next, two lateral incisors in the upper and lower jaws grow alongside the central incisors and by time a child reaches 15 months, they usually have a full set of eight incisors - the biting or cutting teeth.
- The next teeth to appear in the baby's mouth are the first molars which help the baby grind food. Two first molars in each jaw emerge and are positioned one space away from the incisors to make room for the canines to grow in-between. The first molars should have developed by around the age of 19 months
- The canine or cusped teeth follow, with two usually appearing in each jaw by the age of 23 months. These teeth are used for tearing and allow the baby to manage more textured foods.
- Finally, the second molars appear, again two on the upper jaw and two on the lower jaw and complete the set of 20 milk teeth at around the age of 27 months.
General timeline for milk tooth development
The pattern in which milk teeth emerge can vary from baby to baby but in general, the following timeline applies:
- At around 15 months, 8 teeth are usually present
- At around 19 months, 12 teeth are usually present
- At around 23 months, 16 teeth are usually present
- At around 27 months, 20 teeth are usually present
Once the set of primary teeth is complete, the jaws of the baby grow to make room for the permanent teeth which begin to appear at around 6 years of age. The milk teeth then begin to shed over the next 6 years and are replaced by a full set of permanent teeth by around the age of 12 years.
Caring for milk teeth
Although milk teeth are temporary, they still need to be kept free of tooth decay and require careful maintenance. Tooth decay can occur very early on in a baby's life and is referred to as "baby bottle tooth decay" or "nursing mouth syndrome." The condition occurs if the baby's teeth are frequently exposed to sugary liquids for prolonged periods.
Ways to prevent milk tooth decay are similar to those for preventing adult tooth decay and include maintaining good oral hygiene and not allowing an infant or child to fall asleep with a bottle containing formula, fruit juices or sweetened liquids.
Healthy milk teeth help a child to eat, chew and speak normally and decayed teeth can hamper the child's ability to eat normally, therefore affecting growth and development. In addition, a decayed primary tooth can lead to infection that may damage the permanent tooth growing underneath.
Reviewed by Sally Robertson, BSc