Have you ever wondered how or when your teeth develop, or what teeth come in first? In this blog, I will try to answer some of those questions. There are of course variations in growth and development, so this information is what is considered normal. Lets start with the baby, or as we call them, primary teeth.

There are 20 primary/baby teeth. Four incisors (front teeth), two canines, and four molars in each arch.  Primary teeth begin developing (calcifying) at around 5 months in utero. By birth, all the baby teeth have some development. They are all forming in the jaws. Good healthy prenatal care while the teeth are calcifying  is very important. If an infant has a very high fever, lack of nutrition, or certain medications it may cause a problem with the calcification of the teeth at that time.  It may show up as a bad spot or freckle on the teeth. The bad spot will be in the area that was calcifying during the illness.

Around 6 months of age, the first baby teeth begin to erupt. Usually the bottom front teeth erupt first. The baby teeth continue to erupt until about age 2, give or take 6 months. From my experience, if a child is late getting their first baby tooth, the rest of the eruption will be delayed, including the permanent teeth. More important than the time of eruption, is the sequence of eruption.

Dental age and chronological age vary a lot. For example, we call a 12 year molar a 12 year molar, because the average age it erupts is 12. Well, sometimes it comes in at age 10 and sometimes it comes in at 14….so the average is 12. Age is a good reference, but it is a lot less important than the sequence. If your 12 year molar erupts prior to the 6 year molar, then there is a problem!

There are 32 permanent teeth. Four incisors, two cuspids, four premolars, and six molars in each jaw.  Permanent teeth begin calcification around 6 months old, however, the first permanent tooth does not erupt until about 6 years old. This age is crucial for good healthy teeth. This is when fluoride has its greatest effect on cavity prevention. As the tooth is forming (calcifying), the fluoride becomes part of the tooth. The addition of fluoride into the tooth structure makes the tooth less soluble to the acids produced by bacteria that cause cavities. It makes the tooth harder and more resistant to tooth decay. After a tooth has formed or erupted the anti-cavity properties of fluoride is only topical. Children that are raised on well water should be evaluated by their dentist to determine if additional fluoride is needed. Fluorosis, too much fluoride, can cause damage to the teeth, so it is important to properly evaluate an infant/child’s fluoride intake for optimal cavity prevention.

The first permanent teeth to erupt are usually the first (6 year) molars. These teeth erupt behind the last baby molars. The first front teeth to erupt are usually the lower front teeth (central incisors), followed by the upper central incisors. The other front teeth erupt shortly after. This is a good time for an Orthodontist to evaluate a patient.  At roughly age 9, a child will have four permanent front top and bottom teeth, as well as the four first molars.

Most kids will get the remainder of the permanent teeth around age 12. As I said before, this varies greatly. I have seen kids with complete adult teeth by age 10 and others not losing the last baby tooth until 16 or older! Both can be normal eruption. Wisdom teeth, or third molars generally erupt around 18-21 years old.

Just in case, lets mention knocked out teeth. With summer in full swing, this is the time I see the most dental injuries. What do you do if you are at the lake and your best friend knocks a front tooth out?

Always handle the tooth from the crown. The best thing you can do is to put the tooth right back into the hole (socket) that it came out of and go to the dentist. If the tooth is dirty, gently rinse it off with clean water, DO NOT scrub the root of the tooth. If the child is old enough not to swallow the tooth, and you cant get it back into the socket, just place the tooth in the mouth (b/n your cheek and gum) and leave it there until you get to the dentist. Placing it in milk or water is great, but not always available. Most importantly, do not scrub the root, do not let the tooth dry out, and get to the dentist as soon as possible. Many teeth can be saved if you follow these tips.

I hope some of this information was helpful. Have a safe summer and thanks for reading!


dr. ernest


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