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What Color Is a Cavity?

Updated: Apr 19, 2023

Cavities are not monochrome because they can present as different colors depending on the stage of tooth decay that they're in. The early cavities will start off as one color but if it is left untreated and permitted to grow, the color will start changing. The color usually becomes darker and darker as the decay becomes more mature.

cavity on molar with old filling
cavity on molar

The color of a cavity at each stage of tooth decay:

Color of pre-cavities

The color of pre-cavities or very early first stage of tooth decay actually looks white. That means they don't look anything like what you typically picture cavities as such as the brown or black color.

pre-cavity (decalcification of enamel)
pre-cavity (decalcification of enamel)

The color of all these pre-cavities are always white in color. It may be a couple of white spots or a white streak. The whiteness in the enamel signifies that the tooth is decriminalizing. In other words, the tooth is losing minerals and becoming weaker.

If left untreated, these white spots will eventually progress to the next stage of decay and become a small cavity. The color will also consequently change from white to a light brown.

How to treat white spot lesions

Since this white color on your teeth are only pre-cavities, it is actually fabulous news for you if you manage to catch them at this stage. Demineralized white spot lesions on your enamel can be reversed. In other words, this pre-cavity can be stopped and fully reversed!

There are only two ingredients in this world that can reverse this stage of tooth decay and luckily for you, they come in the form of toothpaste. Your toothpaste must contain either fluoride or hydroxyapatite.

There isn't anything special that you need to do, you just need to brush your teeth for at least two minutes twice a day with said toothpastes. As long as you maintain your oral hygiene, you should be able to reverse these lesions.

However, you should be aware that the "white color" will most likely stay even if the cavity has stopped progressing. It won't "un-white" itself in the process.

Studies about remineralization

This study showed that hydroxyapatite toothpastes actually remineralized the teeth more effectively than the traditional fluoride ones.

In case you needed further proof, here is another study displaying results that a 10% concentration of nano-hydroxyapatite toothpaste can remineralize early enamel caries.

Last but not least, here is a study showing that fluoride can remineralize carious lesions.

The color of small cavities

Once the pre-cavities become small cavities, their color changes from white to light brown. Since the light brown color is a stark contrast from people's normal tooth color, most people will start to notice it at this stage.

Here is a picture of a small cavity on the chewing surface of a molar. What it looks like is a light brown dot with a darker halo around that dot. The color is very distinct from the healthy tooth structure which looks pearly white.

decay on chewing surface of molar
decay on chewing surface of molar

Just to drive the point home, here is a small cavity on the side of a molar. Once again, the color is a light brown and the size is fairly small in comparison to the overall tooth.

small cavity on side of molar
small cavity on side of molar

How to treat small cavities

These light brown colored small cavities should be excavated and replaced with a cavity filling. The reason is because the decay in those two photos already show the tooth as being cavitated, meaning a hole is already forming.

What to expect for a tooth filling procedure:

  1. Administer local anesthesia to numb the tooth.

  2. Drill out the decayed part of the tooth.

  3. Apply conditioner, primer, and bond to the tooth.

  4. Restore tooth with a tooth filling composite resin.

  5. Light cure it to harden it and make it set.

  6. Adjust the bite.

  7. Polish the filling and you're done!

The whole appointment should take about 30-45 minutes total. It will be completed in one visit as well so it does not detract too much time away from your day. The only thing you need to be aware of is that you will need to be numb for the procedure so you may have to wait about 2-3 hours for the anesthesia to wear off prior to eating.

What color is a medium sized cavity?

Untreated small decay will grow into a medium sized cavity and once it does, the color will darken into a brown color. It will no longer be light brown but will now be a regular brown color. If you compare it to its smaller counterpart, the brown is much darker shade. It basically means that the decay has been maturing.

medium sized cavity on molar
medium sized cavity on molar

How to treat mid-sized decay that is brown in color

Tooth decay that is brown in color and of this size definitively need a cavity filling. These lesions are irreversible so the only way to stop them from progressing is to drill them out and then fill them back in with tooth filling.

What to expect for a cavity filling procedure:

  1. Administer local anesthetic - Lidocaine, to numb the tooth.

  2. Clean out the decay with a high speed drill.

  3. Apply a conditioner, primer, and bonding to the tooth.

  4. Place a liner at the base of the cavity to help protect the nerve.

  5. Fill the tooth in with a composite resin.

  6. Light cure the tooth to make it hard.

  7. Adjust the bite so that it feels even.

  8. Polish the filling to make it smooth.

Once you're done with the filling procedure, you just need to brush and floss the tooth as if it was any other one. There isn't anything special that you need to do to take care of it. Of course, it always helps if you minimize the sugar intake in the future so that you don't get recurrent decay!

Alternatively, sometimes if the cavity is greater than 50% of the entire tooth structure, you may need a dental crown instead. This will provide better structural integrity for the tooth instead of having a big filling on it.

What's the color of large cavities

Large cavities are usually a dark brown or even black color. This makes them visually distinctive from the smaller sized decay, which is a very light brown color. The color turns dark because as the decay grows, it affects more of the tooth and it starts to pick up a lot of staining as well.

large cavity on molar
large cavity on molar

The black color of this cavity comes from the extensive decay that reaches deep into the tooth. All of the tooth structure, which has changed to this color will need to be removed.

How to treat large cavities

For a cavity of that size in the picture above, a simple tooth filling would be insufficient because the decay has already reached the nerve. In order to treat the nerve, a root canal will need to be completed first which involves extracting the nerve from the tooth.

This is a necessary step because that treats the nerve. A cavity filling does not treat the nerve. After the nerve is removed from the tooth, the missing tooth structure will need to be restored with a dental crown.

When that much of the tooth is missing, a filling does not provide enough structural support. That is the reason why a crown is needed.

Can tooth decay be a different color other than brown or black?

Decay will usually look like a shade of brown or black depending on how advanced it is. Aside from that it doesn't typically look like any other color. The only exception would be if you had a large cavity and the tooth had a big hole in it.

That hole can be a food trap so whatever you're eating may get stuck inside of the hole.

  • If the food you were eating was orange, the cavity may appear orange.

  • If the food you were eating was green such as a piece of lettuce, the cavity can appear green.

Therefore the color of a cavity may be influenced by whatever colored food that you're eating because it can get stuck in the hole. Although to be technical about it, the actual color of the decay doesn't change though. It's merely the food being lodged within the cavitation that gives it the change in color.


The color of a cavity is generally on the brown to black spectrum. The only exception would be the pre-cavities which show up as a white lesion.

The rule of thumb is that smaller cavities tend to be a lighter shade of brown. If the decay is left untreated and allowed to grow, the color will start to darken as it matures. Ultimately it will end up as a very black looking hole once it reaches the end stage of decay.

Now that you know what color tooth decay is, in case you were interested in knowing what cavities look like in general we do have an entire article dedicated to it! However just be aware that the only true way to know if you have one is if you go in for your dental check up.

If you happen to have some decay in your teeth and you're looking for a cavity filling, our dentists in long island city can help you if you happen to be in the NYC area.



David Chen 200 x 200.jpg

About the author: Dr David Chen, DDS

Hello, I'm Dr Chen and I'm an actively practicing dentist in Long Island City, NY. I graduated from Columbia University College of Dental Medicine in 2016 but prior to going to dental school I was already working in the dental field. It's been more than a decade since I first got to know dentistry and let me tell you, time flies by quickly. Since then I've developed a fondness for writing, which is how this all got started!

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Medical Disclaimer:

This blog is purely meant for information purposes and should not be used as medical advice. Each situation in your mouth is unique and complex. It is not possible to give advice nor diagnose any oral conditions based on text nor virtual consultations. The best thing to do is to go in person to see your dentist for an examination and consultation so that you can receive the best care possible.

The purpose of all of this oral health information is to encourage you to see your dentist and to inform you of what you may expect during your visit. Due to the unfortunate nature of dentistry, there isn't really any true home remedies that will get rid of dental problems. Roughly 99.99% of them require in-person intervention by a healthcare professional.

Hint: That is the reason why you can't eliminate seeing dentists in your life!

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