How to Tell if You Have a Cavity

  • by GR0
  • 7 min read

Keeping up with your dental hygiene is super important, especially if you want to avoid getting cavities. We’re all told from an early age how critical it is to brush twice a day, use floss, and avoid eating too many sweets or drinking sugary sodas. But even if you follow all the right advice to the letter, you might still occasionally get tooth problems.

The main issue is that it’s hard to know whether you actually have a cavity or if you’re suffering from general tooth sensitivity. Let’s break down how to tell if you have a cavity by looking for a few major signs.

What Are Cavities? Where Do They Come From?

Let’s start with the basics. Acavity is a damaged area in the hard surface (or enamel) of your teeth. Your teeth are comprised of a few major parts: 

  • There’s the outer shell of enamel and tooth material, which makes up the surface of your teeth
  • Next is the dentin layer, which is softer but still relatively tough
  • Then there’s the pulp, which is beneath your teeth that forms a softer layer to prevent your teeth from being too brittle
  • Last is your teeth’s roots, which are connected to the nerves that go into your jaw

A cavity can technically occur anywhere, reaching all the way down into your teeth’s roots if it’s left untreated. But most people experience cavities as tooth decay in the first layer of enamel. Over time, cavities develop into openings or holes and can lead to serious tooth problems.

How Do Cavities Develop?

Cavities are primarily caused when bacteria grow unchecked on the surface of your teeth and eventually chews through your teeth's enamel and inner material.

Specifically, cavities occur when plaque forms over your teeth and isn't treated. Dental plaque is incredibly common and you can't really avoid it; it's created when you eat food or drink liquid and bacteria in those substances sticks to the surface of your teeth.

It can become a serious problem if you eat a lot of sugars or starches. When those materials aren't properly cleaned off your teeth, bacteria in your other food can feed on those materials and spread, forming an even larger amount of plaque. As plaque hardens, it can become harder to remove and even creates a shield for bacteria to continue growing and reproducing.

Bacteria don’t literally chew through your teeth, though -- we just couldn’t resist the pun. 

Instead, as bacteria reproduce and plaque spreads, acid is produced that eats away at the minerals in your enamel. This gradually causes erosion, opening tiny holes in your enamel and allowing bacteria to spread even further and deeper into your teeth.

Eventually, the bacteria could reach the “dentin” of your teeth, which is the layer after enamel. It’s much less resistant to acid and can even lead to bacteria reaching your teeth’s nerves, which can cause sensitivity and rotten teeth.

In summary:

  • Cavities are caused by bacteria and plaque producing acid
  • If that acid is left unchecked, it’ll eventually cause holes and other damage to your teeth
  • The damage can spread over time and lead to even worse dental problems

How Long Can Cavities Be Left Untreated?

Cavities should always be taken care of right away. The longer cavities are allowed to persist, the deeper they can become.

If cavities go too far, they may reach the roots of your teeth. When this occurs, the only option is a root canal: a surgical procedure that requires dentists to remove the pulp and roots of your teeth and fill them in with a special substance to prevent bacteria from spreading even further into your jaw.

Since root canals are both uncomfortable and expensive, it’s always better to visit a dentist and get any cavities treated as soon as you think you might have one.

Signs That You Have a Cavity

It’s usually pretty easy to tell if you’re developing a cavity since there areseveral signs that go along with their development.

Tooth Sensitivity

The most obvious sign is tooth sensitivity. Sensitivity is distinct from pain, as your teeth may not actually hurt or sting when you eat or drink. Instead, tooth sensitivity is characterized as increased sensitivity to pressure or temperature, or certain foods. Your teeth may tingle or burn when they come into contact with certain materials or food items.

The most common things to induce tooth sensitivity are:

  • Cold drinks
  • Sugary drinks
  • Hot drinks like coffee
  • Candy and other sugary foods
  • Hard foods like certain vegetables or hard-crust bread

Constant Pain in Your Teeth

Naturally, constant pain in your teeth is also a serious sign of significant tooth decay. It also likely means that one or more cavities have reached either the dentin or the roots of your teeth and need to be filled in right away. In the worst-case scenario, constant pain in your teeth could indicate the need for a root canal.

Pain in your teeth could be endless or it might only occur when you eat certain foods or when you bite down. Either way, be sure to contact your dentist ASAP.

Bad Breath

Another common sign of cavities is bad breath. That's because cavities are caused by pockets of bacteria that continue to feed and grow on the starch and sugar you consume. As the bacteria reproduce, they create a smelly substance that can negatively affect the smell of your breath.

In fact, it’s pretty similar to general halitosis: the scientific term for bad breath from bacteria.

If you have bad breath constantly, even when using mouthwash and frequently brushing your teeth, it may be a sign that cavities are infecting your teeth, acting as safe harbors for bacteria. See a dentist to know for sure.

Tooth Discoloration

Lastly, you may have a cavity if your teeth showcase significant discoloration. Regular teeth should be off-white in color (without being too yellow, of course). If your teeth or spots on your teeth start to showcase colors like:

  • Brown
  • Deep yellow
  • Black

Then it may be a sign that your teeth are starting to develop cavities. Cavities can change the color of your teeth by rotting the enamel from the inside out, leading to general tooth decay and preventing your tooth’s tissues from getting the minerals and nutrients necessary to look healthy.

What To Do If You Have a Cavity

The best thing to do is to not get cavities in the first place. Following a rigorous dental hygiene routine, involving brushing with an electric toothbrush multiple times per day, using floss, and usingfluoride-free toothpaste, will go a long way toward ensuring that your chances of getting a cavity are very low to start with.

Ourelectric and sonic toothbrush is a perfect example of the prime cavity-fighter. Thanks to its smart design, waterproof exterior, and fast charging capabilities, it’s a perfect electric toothbrush tool to help you avoid getting cavities at all.

But you can never fully guarantee that you won’t get a cavity. Our teeth are actually lined with lots of tiny divots and pores: these are perfect spots for bacteria to embed themselves and reproduce. Even folks who brush their teeth regularly still occasionally get cavities, especially between their teeth where their toothbrush’s bristles can’t easily reach.

If this happens to you, there’s no need to worry. A dentist can fill in your cavities as soon as you make an appointment. These appointments are really routine and only require a mild anesthetic in most cases.

During a cavity filling, a dentist will drill away any of the affected tooth material using a special dental tool. Once the rotten part of your tooth is removed, the dentist will then fill in the empty space using either silver-colored or white-colored material depending on your preferences. This restores your tooth to its original shape and prevents bacteria from affecting the same tissue again.

However, cavity fillings don’t prevent that tooth from getting infected once again. You’ll still need to maintain an excellent dental hygiene routine in the future to prevent cavities from affecting you in the future.


Ultimately, there are lots of ways to tell if you have a cavity. The best way, however, is to regularly visit your dentist: a twice-yearly visit is recommended by most organizations. During routine checkups, dentists will probe your teeth with special tools and check for signs of decay. They may occasionally take x-rays to see if they can spot potential cavities before they become a problem.

By visiting a dentist regularly and checking for the signs discussed above, you'll be able to stay on top of any cavities as they develop and prevent them from becoming too bad. Remember to use high-quality dental hygiene tools, like ourelectric toothbrush and high-quality toothpaste, to prevent cavities from forming in the first place!


1. What does a cavity look like when it first starts?

Cavities are often invisible in their early stages, however, some begin with a yellowish or chalky look on the enamel of your tooth. The skin may also appear brown or black in more severe cases. However, there are often no obvious red spots.

2. Can you feel a cavity with your finger?

A noticeable cavity will probably look like a dark spot or hole in your tooth. If the cavity has become very large, you may even be able to feel the hole with your tongue or finger.

3. How long can cavities go untreated?

As with other conditions, the longer you wait to treat a cavity, the worse it will get. Cavities can reach the nerve of your tooth in just 3-6 months.

4. Can cavities go away with brushing?

The early stages of a cavity can be reversed by practicing good dental hygiene. Early demineralization, fluoride exposure, frequent brushing and flossing, and professional cleanings are all effective at preventing - and even reversing - tooth decay.

5. Does a black spot on tooth mean cavity?

The most common cause of a black spot on your molar teeth is probably a cavity. Cavities form when plaque, which contains acids, destroys the tooth's enamel. There are times when a black dot can be seen as a sign of a hole in the protective coating of the tooth.