Expert Q&A: Why do I keep getting cavities even though I brush?
Posted on March 5, 2026 in Healthy You
It can be frustrating if you brush regularly but still get cavities. Dr. Jeffrey Chaffin, Chief Dental Officer for Delta Dental of Iowa, helps sort through some of the reasons this happens, and what you can do to minimize your cavity risk in the future.
Q: If you brush regularly and still struggle with cavities, what might be the problem?
Dr. Chaffin: There are a few reasons why you may be getting cavities even though you feel like you brush regularly. One issue is that maybe you are not brushing well, meaning that you are missing areas based on poor technique (I’ll explain more on that below) or not brushing long enough. You should brush for a full 2 minutes. Setting a timer can help keep you brushing for the full amount of time.
Another factor could be that you are not using fluoridated toothpaste. To me, fluoride toothpaste is a must, as the small amount of fluoride that stays in our mouth continues to protect your teeth for hours after you’re done brushing.
Fluoride has a long history of research to show its safety and effectiveness in preventing cavities. A small amount of toothpaste is all you need. For young children, use only a pea-size amount because they will likely swallow the toothpaste (that small amount they swallow won’t harm them).
Q: Can cavities be caused by how you brush, not just how often?
Dr. Chaffin: Yes, how you brush is really important. First, we suggest that you brush two times a day and floss at least once. Flossing is important as it cleans the areas between the teeth that the brush just can’t reach. Many struggle with the flossing technique and only a third of American adults floss daily.1 Flossing is a habit — and changing habits isn’t easy — so find a time of the day that you can floss everyday. For some, the morning is too busy, so they floss at night. There are other types of floss besides string floss that use water to clean between the teeth. Some of these new electronic flossers can be just as effective as regular floss.
We also want you to use a soft bristle toothbrush, so you don’t cause any damage to your teeth and gums.
Also, we want the correct technique to ensure that you get the tooth and the gumline. The best way to understand this is to ask your dental professional to show you the best technique to brush. You need to get every surface of the tooth. The back of the last molar in your mouth is an often-missed area. You need to clean the biting surface, the sides of the teeth and the back of that last one.
One last thought is about rinsing after brushing your teeth. I suggest not rinsing with water because you lose a lot of fluoride when you do that. It’s best just to spit out your toothpaste and not rinse, though that may not be comfortable for everyone.
Q: How big of a role does diet play? Are there certain foods or drinks that increase cavity risk even if you brush? Does snacking or sipping throughout the day make cavities more likely, even if the food isn’t sugary?
Dr. Chaffin: Diet plays a large role in developing cavities. Sugary and acidic food can make you prone to cavities, but even more important is the frequency in which you eat.
Every time you eat, your mouth enters a “cavity prone” time for 15-20 minutes. This is a period where the teeth can demineralize and start to form early cavities. The saliva buffers that acidic attack and stops the cavity prone time. Then, the fluoride that we have in our mouth remineralizes those areas of the teeth. This demineralization/remineralization happens all the time in our mouth and is natural, we just don’t want the demineralization to get ahead because that is when a cavity forms. If we snack too often, our mouth stays in that cavity prone time longer, and we can’t remineralize. This is how the start of a cavity happens.
Q: Do medical conditions or medications make people more likely to get cavities?
Dr. Chaffin: Medical conditions do play a role in cavities, often indirectly. The biggest connection between medical conditions and cavities is dry mouth (or xerostomia). Dry mouth is a common side effect of many prescription drugs. When we have dry mouth, there isn’t enough saliva to wash away the food, which prolongs the cavity prone time. Be sure to consult your doctor about the side effects of medication.
Q: Are some people more “cavity-prone” because of genetics or other reason?
Dr. Chaffin: We generally believe that genetics play a small role in cavities. We often hear, “My parents had bad teeth, so I’m prone to cavities, too.” But it’s less about your genetics and more about your behaviors. Good home oral care will prevent most cavities, combined with the appropriate preventive dental care like dental sealants and fluoride.
However, a small portion of people do have a genetic predisposition to cavities. Some teeth may have naturally deep grooves that make it harder to clean and are more cavity prone. There are a few genetic conditions that play a role in tooth development, but genetics aren’t a cause of cavities for most people. The causes are primarily diet and the quality of at-home dental care.
Q: What changes can you make if you keep getting cavities despite good brushing?
Dr. Chaffin: The first thing is to continue your twice-a-year preventive dental visits and discuss your unique dental history with your dental provider. They may recommend more frequent cleanings, having dental sealants in the deep grooves of your teeth or even prescribe you a high-strength fluoride toothpaste. Prescription toothpastes have almost five times the fluoride than what you can find in the store. These toothpastes are not for everyone, but they can help a lot for people with severe cavity cases.
REFERENCE:
1. National Library of Medicine