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10 February, 2010

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Teeth development in children

The development of the primary teeth begins while the baby is in the womb. At about five weeks’ gestation, the first buds of primary teeth appear in the baby’s jaws. At birth, the baby has a full set of 20 primary teeth (10 in the upper jaw, 10 in the lower jaw) hidden within the gums. Primary teeth are also known as baby teeth, milk teeth or deciduous teeth.

Tooth names
Each type of tooth is named for ease of identification. The names are:

Incisors – the front teeth located in the upper and lower jaws. Each incisor has a thin cutting edge. The upper and lower incisors come together like a pair of scissors to cut the food.
Canines – the pointy ‘vampire’ teeth, on both sides of the incisors in the upper and lower jaws. They are used to tear food.
Premolars – have flat surfaces to crush food.
Molars – larger than premolars, these teeth have broad, flat surfaces that grind food.

Eruption of primary teeth
The term ‘eruption’ refers to the tooth breaking through the gum line. In babies, tooth eruption is also called teething. The timing of tooth eruption differs from one child to the next. For example, one child may cut their first tooth when only a few months old, while another may not teethe until they are 12 months old or more. While the timing may vary, the order of tooth eruption is generally the same. This includes:

The two front teeth (central incisors) in the lower jaw are usually the first to erupt. This occurs somewhere between the ages of six and 10 months.
The two front teeth (central incisors) in the upper jaw erupt between the ages of eight and 13 months.
The lateral incisors, which are the teeth on each side of the central incisors, erupt in both the upper and lower jaws between the ages of eight and 16 months. The lower set tends to erupt before the upper set.
The first set of upper and lower molars (flat-surfaced back teeth) erupt between the ages of 13 and 19 months.
Canine or ‘eye’ teeth sit beside the lateral incisors and erupt in both the upper and lower jaws between the ages of 16 and 23 months.
The second set of upper and lower molars erupts between the ages of 25 and 33 months.

Generally, the average child has their full set of 20 primary teeth by the age of three years.
Development of permanent teeth
The permanent teeth start to develop in the jaws after a child is born. By about 21 years, the average person has 32 permanent teeth: 16 in the upper jaw and 16 in the lower jaw. (In some cases, however, the third molars – commonly called the wisdom teeth – do not develop. A set of 28 permanent teeth is considered normal too. Permanent teeth are also known as adult teeth or secondary teeth.

Loss of primary teeth
Between the ages of about six and seven years, the primary teeth start to shed. The central and lateral incisors in the upper and lower jaws are usually the first to go. Some children are worried about the loss of their first teeth but the tooth fairy, with her cash reward for every shed tooth, usually helps to ease anxiety!

Eruption of permanent teeth
At about the age of six years, the first permanent teeth erupt. These four molars (two in the upper jaw and two in the lower jaw) emerge behind the child’s existing primary teeth. Other permanent teeth, such as the incisors and canines, erupt into the gaps in the gum left by shed primary teeth.

Like primary teeth, the timing for when the permanent teeth come through differs from one child to the next. Generally, the order of eruption and rough timeline for each type of permanent tooth includes:

First molars – between six and seven years
Central incisors – between six and eight years
Lateral incisors – between seven and eight years
Canine teeth – between nine and 13 years
Premolars – between nine and 13 years
Second molars – between 11 and 13 years
Third molars (wisdom teeth) – between the ages of 17 and 21 years, if at all.

Where to get help

Your dentist
Your doctor
Your local council – some have a preschool dental program
School Dental Service, Dental Health Services Victoria Tel. 1300 360 054 8.30am to 5pm, Monday to Friday
Dental Health Services Victoria Information Line Tel. 1300 360 054 8am to 5pm, Monday to Friday
The Maternal and Child Health Line (24 hours) Tel. 132 229
Nurse on Call Tel. 1300 606 024 – for expert health information and advice (24 hours, 7 days)
Royal Children’s Hospital Tel. (03) 9345 5344, 9am to 5pm, Monday to Friday

Things to remember

The average child has their full set of 20 primary teeth by the age of three years.
Between the ages of about six and seven years, the primary teeth start to shed and the permanent teeth begin to come through.
By the age of about 21 years, the average person has 32 permanent teeth – 16 in the upper jaw and 16 in the lower jaw.

You might also be interested in:
Child development (1) - newborn to three months.
Child development (2) - three to six months.
Child development (3) - six to nine months.
Child development (4) - nine to 12 months.
Child development (5) - one to two years.
Child development (6) - two to three years.
Child development (7) - three to four years.
Dental checks - 0 to 6 years.
Teeth care.

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