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How To Know If You Have a Cavity

A cavity can be a quick fix, but it’s important to catch it early. Here’s a guide from Flossy on how to know if you have a cavity.

Last updated on

July 19, 2023

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How To Know If You Have a Cavity

Cavities—and the resulting tooth decay—are among the most common dental conditions, with more than 90% of U.S. adults getting a cavity at least once in their lives. 

Although they can be fixed pretty quickly, it’s important to catch cavities early on. For this reason, we compiled this guide to help you identify a cavity in its early stages so you can make an appointment with your dentist and get it taken care of right away. 

Keep reading to find out what a cavity is, what causes one to form, and how to tell if you currently have one. 

The Fascinating Structure of the Tooth

Before we get to discussing what a cavity is, let’s briefly go over how your tooth is structured. (We promise this will go a long way in helping you understand why cavities form in the first place!)

Each tooth has two parts: a crown and a root. The crown lies right above the gum line and is the pearly-white part that you can see with your own eyes. On the other hand, the root is the invisible part that’s hidden in the gums and provides the tooth’s support. Although many dental conditions are implicated with the root, it’s mainly the crown we’re concerned with when it comes to cavities. 

Cavities form in one of the tooth’s three layers: the enamel, the dentin, and the pulp.

The pulp is the innermost portion of the tooth. It contains lots of nerves and blood vessels and is responsible for providing the tooth with vital nutrients. 

Dentin makes up the tooth’s middle layer and is about 70% of the tooth’s total mass. It contains microscopic tubes and transmits signals between the outer and inner parts of the tooth. 

Finally, the outermost layer of the tooth is called enamel, which is the hardest tissue in the entire body. Enamel is mostly made up of minerals and is responsible for protecting the tooth from outside elements. 

What Is a Cavity?

A cavity is a small hole that forms in your enamel, which can eventually spread to deeper layers of the tooth. Cavities form thanks to plaque, a bacteria-filled film that forms on your teeth and gums. 

Although everyone has a buildup of plaque, too much of it can pose a problem. This is because the bacteria in plaque feed on sugar in your food and release acids that eat away the enamel that’s crucial for protecting your teeth. 

If a cavity isn’t addressed quickly, it can get deeper and make its way into the other layers of your tooth, such as the dentin and even the pulp. Three types of cavities correspond to how far the damage has spread: 

  1. Smooth Surface Cavity: If your teeth are exposed to acid produced by plaque bacteria, then the enamel may begin to lose some of its minerals. If this happens, you may notice white spots forming on your teeth—an early sign of tooth decay. If it isn’t addressed quickly, then the discoloration can turn a darker color, such as brown or black. Eventually, small holes can form in your teeth, which will need to be filled in by your dentist. 

  1. Pit and Fissure Cavity: While it takes years for damage to occur to your enamel, the process is much quicker when the damage reaches the middle layer of your tooth—the dentin. When the damage reaches this layer of your tooth, you will begin to experience sensitivity and pain. In addition, the damage can quickly progress to the innermost part of the tooth—the pulp. 

  1. Root Cavity: When the damage reaches the innermost layer of the tooth—the pulp—you may begin to experience inflammation, swelling, and pain. In addition, damage at this layer may cause bacteria to invade and cause pockets of pus—called abscesses—to form at the bottom of your tooth. This requires immediate treatment as the infection can spread to the rest of your face. 

What Are the Risk Factors for a Cavity?

For the most part, how likely you are to get a cavity has to do with how much sugar you consume and how well you stick to your oral hygiene routine. However, your genes may also play a role in your predisposition to getting a cavity. 

Because your genes control how your teeth develop, you may be more likely than others to develop cavities. For instance, if your teeth didn’t form properly during development, your enamel may be less resistant to plaque bacteria. In addition, crooked teeth—which can also be hereditary—may make it harder to clean your teeth, making them a more welcoming environment to bacteria. 

However—for the most part—the causes of tooth decay have to do with your lifestyle. For instance, eating or drinking sugar feeds the plaque bacteria that live on your teeth and gums. These tend to release acids that contribute to breaking down enamel. 

Clearing away plaque is one of the surest ways to prevent this from occurring, which requires you to brush and floss consistently. However, not following a consistent oral hygiene routine can cause plaque to build up on your teeth and gums, which increases your chances of developing cavities. 

Last but not least, age is another factor that might increase one’s chances of getting cavities. Although cavities can affect individuals of any age, they tend to be more of a problem for older adults. Because older generations received less preventive dental care and fluoride in dental care products, they were more likely to get dental fillings. Over time, these fillings tend to weaken, allowing bacteria to accumulate around them and release acid that leads to tooth decay.

How To Tell if You Have a Cavity

Although a cavity can be easily fixed, it’s important to address it as soon as possible (otherwise, it can spread to deeper layers of your tooth). 

Identifying a cavity in its early stages may be difficult as it may not show any signs at all. This is exactly why going to your dentist for regular checkups is so important, as they may be able to identify it early on. However, once a cavity begins to progress, there are sure symptoms that you’ll be able to pick up on. 

Here are four signs that you may have a dental cavity: 

1. Staining: A cavity may first appear as a tiny white spot due to the breaking down of minerals in your enamel. As the decay progresses, the stain can become darker. So, if you notice a brown or black spot on the surface of your tooth, then it’s a telltale sign of a cavity. 

2. Hole in Your Tooth: If the colored spot on your tooth gets worse, then you will likely end up with a small hole in your tooth that will gradually increase in size. For the most part, you’d be able to feel the hole if you ran your tongue over your tooth. You may also be able to see it in the mirror. However, for those tricky spots, you may not realize there’s a hole at all, which makes regular trips to the dentist so important. 

3. Sensitivity to Hot and Cold: There are various causes of tooth sensitivity. However, if eating cold or hot foods causes pain, it’s good to get checked out for a cavity. This is because the middle layer of your tooth—the dentin—contains microscopic tubes connected to your tooth’s nerve endings. Feeling sensitivity can signify that the cavity has progressed to the middle layers of the tooth, which needs to be addressed right away. 

4. Toothache: Similar to the above reason, feeling pain is a sign that the damage has progressed towards the inner layers of your tooth. Whether you feel a sporadic toothache or constant pain, it’s a good idea to get yourself to the dentist as soon as possible to get the cavity filled in. Otherwise, it might be necessary to undergo a root canal—something to avoid if it’s possible.

Preventing Cavities Isn’t Always Easy

Even if you have your oral hygiene routine down pat, you may still experience one of the telltale signs of a cavity. Whether you’re noticing a small stain on your tooth, sensitivity to extreme temperatures, or just a plain toothache, then it’s a good idea to see your dentist as soon as possible. 

Although getting a cavity filled in is nobody’s idea of fun, Flossy’s network of professional dentists will make the experience as quick and painless as it can be. 

Our Sources:

Dental Caries (Tooth Decay) In Adults (Age 20 to 64) | NCBI 


Sensitive Teeth | The Journal of the American Dental Association 

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