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How To Tell if You Have a Cavity: 7 Signs

by Aura Glow on Mar 11, 2021

How To Tell if You Have a Cavity: 7 Signs

Cavities can happen to anyone and they often do. According to the National Institute of Dental and Craniofacial Research, 26% of adults ages 20 to 64 have untreated decay and 92% of adults in that age range have dental caries (also known as tooth decay) in their permanent teeth. 

Before we dive into the signs and symptoms behind a cavity, it’s important to understand what a cavity is. Simply put, a cavity is a hole or damage to the two outer layers of a tooth called the enamel and dentin. The enamel is the white outermost layer that you can see when you smile. Dentin is the yellow layer just underneath the enamel. 

Both of these layers serve as a protective barrier for the tooth’s tissue called the pulp, as well as for the nerve endings and blood vessels that make up a tooth. When the outermost layers of the tooth have been destroyed by bacteria, that’s when the tooth begins to break down, often causing toothache and discoloration before progressing into more painful and obvious signs of a cavity. 

While tooth decay and cavities are common among adults and children, cavities are largely preventable and if your tooth is in the very early stages of decay, there are measures you can take to stop it from worsening. That’s why it’s so important to know how to tell if you have a cavity to keep your smile healthy and prevent further (and more painful) dental issues.

7 Signs of a Cavity

As a cavity progresses, there are different symptoms that come with the different stages of tooth decay. Early on, there might be little to no visible signs of a cavity, but as tooth decay progresses and more of the enamel is worn away, you can start to notice discoloration or even holes in your tooth. Here are some important warning signs to be on the lookout for as you brush and floss. 

1. Visible Discoloration or Dark Spots

Discoloration and spots on a tooth are some of the most visible signs of a cavity. A cavity’s color can range from white to black and even yellow. Each color can be an indication of what stage of tooth decay that your tooth is undergoing. 

Chalk-colored Spot

Chalk-colored spots aren’t always easy to spot on white teeth but if you see white spots on your teeth, this is a sign that demineralization is happening. Demineralization happens as acids left behind by food particles in your mouth slowly break down calcium and minerals in the tooth enamel. This can lead to more stains on your teeth. 

Yellow Tooth

There are several causes for a yellow-stained tooth. Long-term tobacco users and aging adults often experience yellowing teeth. Luckily, these stains can be helped with teeth whitening products. However, if only one tooth is yellow-stained, this can be a sign of tooth decay. It’s best to visit your dentist for a professional recommendation on how to mitigate further damage. 

Grey Tooth

Similar to yellow teeth, there are several causes for a grey tooth. Medication like tetracycline can cause children’s teeth to turn grey and even some root canal medications can cause greying teeth in adults. Tooth decay is also a factor because as a tooth decays, it can cut off the tooth’s blood flow, causing it to turn grey and die. 

Brown Spot

Brown spots on teeth are often symptoms of tooth decay. Brown spots occur as plaque continues to destroy the tooth’s enamel and can also come from the dentin underneath the enamel, which is darker than the white color of enamel. 

Black Spot

As part of the tooth continues to decay, the discoloration will darken over time. If you’re noticing a spot that’s turning black in color, it’s time to make an appointment with your dentist as a black spot can signal worsening decay. 

2. Sensitivity to Hot and Cold

When a tooth decays, the outermost layers that protect a tooth’s nerve endings start to wear away. This means that food and drink can seep into those sensitive areas of the tooth, causing sensitivity to temperature. If your tooth is sensitive to both hot and cold and this continues for more than a few days, make an appointment with your dentist to see if it could be caused by a cavity.

3. Holes or Pits in Teeth

One of the most advanced stages of tooth decay is a hole or pit in your tooth. As your tooth continues to break down, it will eventually cause a hole or pit to form. You might notice this in the mirror or when you run your tongue over the area, but depending on where the hole is, you might not be able to see it. If you notice a hole in your tooth, make an appointment with your dentist as soon as possible as this is a clear sign you need to have a cavity filled. 

4. Bad Breath or Unpleasant Taste

Cavities are caused by bacteria eating away at the tooth’s outermost layers. This bacteria produces waste and that waste can cause unpleasant side-effects. People with cavities often experience bad breath and a foul taste in their mouths. If you’re experiencing either of these symptoms, it could be a sign that you have a cavity. 

4. Biting Pain

Aside from a dull ache that can come with a cavity, you might also experience pain when biting down. If your tooth pain worsens when you bite or chew, especially when it occurs in a tooth toward the back of your mouth, this can be a sign you have a cavity and should seek dental help before the pain interferes with eating. 

5. Swollen or Bleeding Gums

Sometimes cavities happen near the gum line, and not only affect the tooth but also the gums. If your gums are swollen or often bleed when you brush and floss, set an appointment with your dentist. It might be a cavity or gingivitis — but both are important to have checked out by a professional. 

6. Pus

If you spot pus near or on your tooth, this is a sign that your tooth has abscessed and needs to be handled right away. Abscesses are very painful and can cause fevers and swollen glands. It’s important to seek dental treatment as soon as possible as an untreated abscess can spread and cause even more damage to your mouth.  

7. No Symptoms 

Unfortunately, not all cavities will show early signs and symptoms. As a cavity gets worse, that’s typically when the pain starts and the visible signs start to emerge. Regular trips to your dentist will help you catch and prevent cavities as they form. 

What Does a Cavity Feel Like? 


As a cavity progresses past the enamel of your tooth to the nerves underneath, you’ll begin to experience some pain and sensitivity. This might happen after eating sweets or hot and cold foods. The pain might be a dull ache or could present as a sharp pain, depending on where the cavity is and what stage of tooth decay it’s in.

What to Do if You Think You Have a Cavity

If you’re experiencing pain or have a concerning spot, our best advice is to set up an appointment with your dentist. No matter the stage your cavity is in, your dentist will be able to help you treat and prevent future cavities from forming.

Bottom Line: Cavities are Preventable if Caught Early

Healthy oral hygiene habits and regular trips to your dentist are two of the best ways to catch and prevent cavities early on. Here are a few more ways you can prevent future cavities from forming and impress your dentist during your next check-up: 

  • Brush your teeth twice a day for two minutes each time 
  • Floss at least once a day 
  • Try to cut back on sugary drinks and food 
  • Introduce products with fluoride into your oral hygiene routine  
  • Rinse with mouthwash 

While cavities can happen to even the most diligent brushers, taking the steps above can help reduce the number of cavities you have and improve the health of your teeth. And with numerous health benefits of smiling, there’s even more reason to ensure your smile is the healthiest it can be.Â