The Early Life of TeethBaby teeth — what your child’s dentist calls primary teeth — start showing up when a baby is about 6 months old. It’s a steady march of progress for the next two years as the mouth fills with 20 teeth — 10 on the top, and 10 on the bottom. Then, around age 6, they start to fall out and make room for 32 adult — or permanent — teeth. Here’s how it all happens.
Teeth start their journey below the gum line. They start to form around 6 to 8 weeks of pregnancy. The enamel-covered crowns of the tiny tooth buds form first, and then the roots form. Teeth are made of layers of different kinds of tissue. The outer layers are enamel on the top — the hardest tissue in the body — and cementum on the root. Just under these layers is the dentin. Cementum and dentin are as hard as bone. And in the center of the tooth is the pulp, a soft tissue with nerves and blood vessels.
After the teeth form in the jaw, they gradually push their way up through the gums to erupt in the mouth. The teeth erupt one by one starting around 6 months and finishing by age 3. This can make a child’s gums sore, and often causes crying that can be soothed by a teething ring or gentle rubbing of the gums.
After the incisors, the molars start to arrive. These are the larger teeth toward the back of the mouth. They have bumpy, grooved tops that help grind food. There are four molars in each jaw. The first molars come in between 13 to 19 months of age. The upper molars arrive before the lower.The first teeth to erupt in the mouth are on the bottom. The lower central incisors — the middle two teeth on the bottom — show up between 6 and 10 months of age. Incisors are the narrow-topped teeth in the middle front of the mouth. There are four on the bottom, and four on the top. A few months after the lower central incisors come in, the two front teeth come in. These upper central incisors erupt from 8 to 12 months. Next come the upper lateral incisors — the teeth just next to the middle teeth. The upper ones come in from 9 to 13 months, and the lower from 10 to 16 months of age.
After the first molars, the canines come in. Canines — also called cuspids — are the pointy-looking teeth right next to the incisors. There are two on the top, and two on the bottom. They show up between 16 and 23 months of age, usually the upper and then the lower.
The second molars are the last to arrive. They erupt from 23 to 33 months of age, starting with the lower set.
Baby teeth fall out in roughly the same order they came in, starting around age 6, and are replaced by their adult versions. The incisors fall out from ages 6 to 8, starting with the middle teeth that arrived first. Then the first molars drop out from ages 9 to 11. After those, the canines depart between ages 9 and 12. The second molars are the last to go, from ages 10 to 12.
Permanent teeth form just below the baby teeth. As the roots of baby teeth start to dissolve so they can fall out, the permanent teeth are pushing upwards. So as your child’s mouth loses baby teeth, it starts filling with adult versions of his or her baby teeth, plus some extras — such as the bicuspids. The bicuspids are next to the canines, and they have two points — or cuspids — on top. They’re also known as the premolars. They are the teeth that replace the baby molars. There are four on top, and four on the bottom. In an adult mouth, there are three molars on each side of the jaw, top and bottom, for a total of 12. They’re named from front to back as first, second, and third molars. The first molars come in about age 6 and the second molars about age 12. The third molars — also known as wisdom teeth — arrive between the ages of 17 and 21. And now the teeth have finally finished their journey and are settled in for the long haul!
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