written by Taton Allen, DDS, ABC Pediatric Dentistry

Do your children seem to have cavities every time they visit the dentist? Have you ever wondered why? Dentists often hear parents say that their family just has “bad teeth.” Examples are given like: grandpa had all of his teeth removed by the time he was 20 because his teeth were so bad, or that either mom or dad has cavities every time they visit the dentist. If this describes your family, do you just expect your family to have cavities when you visit the dentist?

So, what is the truth? Why do your children always have cavities? Does your family really just have bad teeth?

Well, the answer is a little more complicated than just “bad teeth.” In order to understand why you or your children keep getting cavities, you need to understand what is necessary for a cavity to form.

Three things are necessary for a cavity to form: First, you need a tooth. Second, the right kind of bacteria have to stick to the tooth. Third, those bacteria need sugar. If bacteria are not removed from teeth through proper oral hygiene, the bacteria will take the sugars eaten and convert them into acid. The acid then dissolves the tooth. The first sign that a tooth is being dissolved by the acid is a chalky white appearance on the surface of the tooth. So, look for those white marks and make sure you are keeping those areas especially clean.


What makes one tooth more vulnerable to get cavities than others? Well, the tooth can have thin or poorly formed enamel along with deep grooves or fissures. Sometimes teeth fit together tightly. All of these things make the tooth more vulnerable to get cavities because they are harder to clean, or the acids can dissolve them more easily. Fluoride and sealants can help protect and strengthen teeth and decrease vulnerability. So, yes, some people have “bad teeth.” But a “bad tooth” is only one component in cavity formation. You also have to have the right bacteria and sugars. If you remove any one of these three elements, cavities cannot form.


There are hundreds of different types of bacteria in our mouths. Only a handful of those bacteria will cause cavities. These cavity-causing bacteria can be transferred from parents to children, and from sibling to sibling. In other words, if you have cavities in your mouth you can transfer those cavity-causing bacteria from your mouth to your child’s mouth. We will often see two siblings with the exact same tooth vulnerability and similar diets, yet one of them always seems to get all the cavities. It could be that the child getting the cavities has a higher count of the bad bacteria in their mouth compared to their sibling. By brushing two to three times a day and flossing every day, you can lower the count of the bad bacteria in the mouth.


Nearly every type of sugar can cause cavities. Sucrose, glucose, maltose, lactose, and fructose can all be made into acid by cavity-causing bacteria. It is not the amount of sugar that is eaten that causes cavities, it is the frequency and duration with which the teeth are exposed to the sugars that cause cavities. For example, if your child has a big birthday cake, and eats the entire cake in 10 minutes, that would be better for their teeth than if they ate one bite every five minutes for three hours. The reason: Bacteria stay in contact with the sugars from the cake for a longer period of time and this gives them more time to make acid. The biggest cause of cavities in young children is a drink of something besides water at bedtime or during the middle of the night because the sugars stay on their teeth most of the night. Remember, if your child snacks throughout the day, their risk of getting cavities increases dramatically.

I recommend that children have structured meals and snacks with start and stop times. This helps give their teeth the best chance of being cavity free.

So, does your family have bad teeth? Maybe. But even if you do, you can usually prevent cavities by brushing bacteria off your teeth two to three times a day, for two minutes each time you brush, flossing daily, and limiting the frequency and duration of sugar to the teeth. These precautions will help ensure your best chance of a great report at your next dental visit.