Are Cavities Contagious? The Shocking Truth

The flu. Chickenpox. Measles. There are a lot of contagious illnesses out there. But, are cavities contagious? It seems like a crazy idea at first. But, there’s more truth to it than you think. Discover the contagious aspect of cavities, and what you can do to prevent them.


What Are Cavities?

In simple terms, cavities (also called caries or tooth decay) are holes in your teeth. These holes are permanently damaged areas on your enamel, the hard outer layer of your teeth. What’s worse, these holes are constantly expanding. So, a cavity can only get worse.

There are three types of cavities: pit and fissure, smooth surface, and root cavities. These are all classified based on the surfaces of the teeth that they impact.

Cavities are also extremely common. Over 90% of people in the United States have had cavities. Chances are, you know someone that has a cavity or has had one. And that’s why it’s important to understand if they really are contagious. 

How Do Cavities Form?

There are various reasons why cavities can form, including contagion. But, how they form happens the same way each time.

A sticky film of bacteria called plaque builds up on your teeth. This bacteria eats sugar and releases acid. The plaque bacteria’s acid destroys your tooth enamel, and the result is tooth decay. When you eat sugary or acidic foods, this process becomes even faster.

If you don’t remove it, plaque turns into a hard substance called tartar. At that point, only a dentist can remove it.

Are Cavities Contagious?

Shockingly, cavities are contagious. You can’t “catch a cavity” like you can catch a cold. However, you can “catch” cavities when you share bacteria with someone who has cavities or poor dental hygiene. Technically, that makes cavities a contagious disease.

The bacteria called streptococcus mutans is the real culprit behind cavities. As with any other contagious ailment, this bacteria can be spread from one person to another. 

And the most common ways to spread cavities? Sharing eating utensils and kissing.

Why Are Cavities Dangerous?

You may think that a tiny hole in your tooth isn’t something to worry about. But, a cavity can quickly become painful. It can even threaten your life.

Since cavities are permanent and constantly expanding, they pose danger over time. Once the cavity eats through your enamel and dentin, tooth decay can reach your nerves. By this point, cavities are excruciatingly painful. And losing your tooth is the least of your worries now.

If you still don’t get treatment for cavities, it can get worse. Tooth decay can spread to your face and lymph nodes. Ultimately, this decay and infection can cause heart disease and strokes. And these are definitely life-threatening conditions.

Cavities Are Even More Contagious For Children

Researchers found that 30% of three-month-olds, 60% of six-month-olds, and 80% of two-year-olds were infected with cavity-causing bacteria. The reason for this is because the contagious cavities were passed on to them by their parents.

No matter how loving and caring parents are, if they have cavity-causing bacteria, they can easily infect their children. But, of course, adults can pass the contagion to other adults just as easily.

How to Prevent Cavities

Luckily, preventing cavities is easy. Here’s what you should do and avoid to lower your chance of catching contagious cavities and developing them.

Prevent Cavity Contagion

Since cavities are contagious, you need to be mindful of who you share bacteria with. If you live with someone who has cavities, or who has poor dental hygiene, monitor what you share.

Avoid eating with the same utensils, sharing water bottles, and kissing with that person. At least until they get treatment for their cavities.

And if you’re the one with the cavity, be mindful of the people you come in contact with. Warn them about your condition and the contagious nature of cavities. And teach them how to take steps to prevent cavities. Finally, don’t share glasses, toothbrushes or kisses with anyone if you have a cavity.

Most importantly, be sure to get treatment as soon as possible.

Prevent Cavity Development

The most important this you can do to prevent cavities is to practice proper dental hygiene. Brush and floss regularly. Ideally, you should brush your teeth twice a day. Cleaning your tongue regularly is also very effective in eliminating cavity-causing bacteria from your mouth.

Fluoride is a natural material that strengthens your enamel. While it can’t reverse a cavity, it can strengthen your teeth against the bacteria that causes it. Use fluoride toothpaste to prevent cavities easily.

One of your greatest natural defenses against cavities is your saliva. It washes away the bacteria before they form cavities. Drink plenty of water to stay hydrated and increase your saliva production.

Since the bacteria that causes cavity contagion feeds on sugar, avoiding sugary foods and drinks can help lower the risk of tooth decay. Regular dental cleanings and oral examinations can also help keep your dental hygiene healthy.

What to Do If You Have a Cavity

Firstly, you need to know how to tell if you have a cavity. Tooth sensitivity, pain, and unusual discoloration are clear signs of a cavity. 

If you notice that you have a cavity, turn to a dentist as soon as possible. The sooner you receive treatment for it, the less likely you’ll develop complications. And even better, you won’t be contagious anymore either.

Your dentist will evaluate the type and severity of your cavity, and they’ll recommend the most effective treatment for it. Common cavity treatments are fillings, dental crowns, and root canals

Even if your tooth is beyond saving, a dentist can recommend an alternative that saves the beauty of your smile.

Save On Your Cavity Treatment

The best way to prevent contagious cavities from destroying your teeth and dental health is with regular dentist visits. However, a lot of people don’t go to the dentist because of the cost. 

Even if they have cavities, they fear the price of the treatments. But that doesn’t have to be the case for you.

With a Carefree Dental Card, you won’t have to choose between your wallet and your dental health. Our dental discount plan can unlock huge savings at participating dentists. Members can save 15% - 50%* per visit in most instances at participating dentists.

Save on all your cavity treatments and sign up for a Carefree Dental Card today!


The Carefree Dental blog is not meant to be a substitute for professional medical advice, diagnosis, or treatment. The text and pictures within the content are intended for information purposes only. Readers should consult with a licensed dentist or healthcare professional before seeking treatment.

The Carefree Dental Card is not insurance and Carefree Dental is not an insurance provider.

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