CHOC Children's
ORAL HEALTH

Anatomy and Development of the Mouth and Teeth

Anatomy and development of the mouth and teeth:

Children's teeth begin developing in the fetus. Good nutrition from the mother during pregnancy is important in the development of the teeth. The mother's diet should have adequate amounts of calcium, phosphorus, vitamin C, and vitamin D. Certain medications, such as tetracycline, should not be taken by the mother while she is pregnant as this can cause harm to the developing teeth of the embryo. There are four main stages of development of the tooth:

  • The first stage begins in the fetus at about six weeks of age. This is when the basic substance of the tooth forms.
  • Next, the hard tissue that surrounds the teeth is formed, around three to four months of gestation.
  • The next stage of development is when the first baby teeth begin to come in at 6 months to 1 year after birth. At this same time, the permanent teeth begin to develop inside the jaws. 
  • Finally, the process of losing the baby teeth begins around 5 to 6 years of age and continues until 11 to 12 years of age, as permanent teeth come into the mouth.

Parts of the tooth:

Each tooth has four main parts, including the following:

  • enamel - the outer layer of the tooth.
  • dentin - the inner layer and the main part of the tooth.
  • pulp - part of the inside of the tooth that contains the nerve.
  • root - the part of the tooth that secures it into the jaw.
Anatomy of a tooth, cross-section
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When will my child's teeth come in?

While every child is different, most of the primary teeth (baby teeth) come in between the ages of four and 12 months. The following are general guidelines for the eruption of the baby teeth:

  • The first tooth to erupt is usually a middle, front tooth on the lower jaw, known as the central incisor. This is followed by the second central incisor on the lower jaw.
  • Next, the four upper incisors usually come in.
  • The above is followed by the first four molars, and the remaining bottom two lateral incisors. Lateral incisors are beside of (lateral to) the central incisors.
  • Then the cuspids, or the pointed teeth, appear.
  • Usually, after the child reaches two years old, the four second molars (the last of the baby teeth) appear.

The teeth on the upper jaw usually erupt one to two months after the same tooth on the lower jaw. There are a total of 20 primary teeth. Usually, about one tooth erupts per month once the teeth have started coming in. There is normally a space between all the baby teeth. This leaves room for the larger permanent teeth to erupt.

Eruption of teeth happens at different times for each child. Below, we have provided average ages of eruption and shedding:

Illustration demonstrating the age of eruption and shedding of teeth, baby teeth
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When will my child's permanent teeth come in?

Your child will begin losing his/her primary teeth (baby teeth) around the age of 6. The first teeth to be lost are usually the central incisors. This is then followed by the eruption of the first permanent molars. The last baby tooth is usually lost around the age of 12, and is the cuspid or second molar. There will be a total of 32 permanent, or adult, teeth.

Illustration demonstrating the age of eruption of adult teeth
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Online Resources of Dental & Oral Health

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It is important to remember the health information found on this website is for reference only not intended to replace the advice and guidance of your healthcare provider. Always seek the advice of your physician with any questions you may have regarding a medical condition. If you think you may have a medical emergency, call your physician or 911 immediately.

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