As seen from the chart, the first teeth begin to break through the gums at about 6 months of age. Usually, the first two teeth to erupt are the two bottom central incisors (the two bottom front teeth). Next, the top four front teeth emerge. After that, other teeth slowly begin to fill in, usually in pairs -- one each side of the upper or lower jaw -- until all 20 teeth (10 in the upper jaw and 10 in the lower jaw) have come in by the time the child is 2 ½ to 3 years old. The complete set of primary teeth is in the mouth from the age of 2 ½ to 3 years of age to 6 to 7 years of age.

Other primary tooth eruption facts:

• A general rule of thumb is that for every 6 months of life, approximately 4 teeth will erupt.
• Girls generally precede boys in tooth eruption
• Lower teeth usually erupt before upper teeth
• Teeth in both jaws usually erupt in pairs -- one on the right and one on the left
• Primary teeth are smaller in size and whiter in color than the permanent teeth that will follow
• By the time a child is 2 to 3 years of age, all primary teeth should have erupted

Shortly after age 4, the jaw and facial bones of the child begin to grow, creating spaces between the primary teeth. This is a perfectly natural growth process that provides the necessary space for the larger permanent teeth to emerge. Between the ages of 6 and 12, a mixture of both primary teeth and permanent teeth reside in the mouth.

If baby teeth fall out after a couple of years, why is it important to care for them?

While it’s true that primary teeth are only in the mouth a short period of time, they play a vital role in the following ways:

• They reserve space for their permanent counterparts
• They give the face its normal appearance
• They aid in the development of clear speech
• They help attain good nutrition (missing or decayed teeth make it difficult to chew causing children to reject foods)
• They help give a healthy start to the permanent teeth (decay and infection in baby teeth can cause dark spots on the permanent teeth developing beneath it)

As seen in this chart, permanent teeth begin to come in around the age of 6.

In some children, the first permanent molars are the first to emerge; in others, the incisors are the first to emerge. By the age of 13, most of the 28 permanent teeth will be in place. One to four wisdom teeth, or third molars, emerge between the ages of 17 and 21, bringing the total number of permanent teeth up to 32.