Updated: Aug 26
Not the most pleasant news to hear when your dentist tells you that you have a cavity. We can picture what is running through your head, "Oh gosh, now I have to come back and get it filled." That we know but do you even know what tooth decay looks like?
If you don't know what cavities look like, we're about to bombard you with more information than you could ever ask for!
Table of Contents
What is a cavity?
The literal definition of a cavity is a hole but it can refer to any sort of hole in your body. However in our case, the type of cavity that we're referring to is in your tooth. This hole is caused by tooth decay and the culprit happens to be the bacteria in your mouth that is processing all of those sweets that you've been eating. Any type of soda, candy, or desserts will do the supply the sugar for cavity formation.
Cavities can form anywhere on your teeth. Your tooth has 5 different surfaces so the decay can penetrate the enamel from any combination of those surfaces. If the decay involves all of the surfaces then it will be a big cavity but if it only involves one surface then it is a small cavity.
How do cavities form?
Cavities require 4 factors to form and it won't happen if it is missing one ingredient:
Basically the bacteria eats the sugar and produces acid as a byproduct. This acid will dissolve the host's enamel but it doesn't happen over night. The acid requires time for it to completely erode the enamel.
It is also important to note that the bacteria work the most effectively and efficiently when the pH of the mouth drops to below 5.5, which is considered the critical pH. The average pH of the oral cavity is around 6.7.
What does a cavity look like?
Have you ever seen what a cavity looks like? We bet that you've periodically had them throughout the years but your dentist has never actually shown you what they actually look like.
Cavities will look different depending on which surface of the tooth they're located on and also the size of the decay. Therefore, we need to show you what every combination of these look like in order for you to really understanding their appearance.
Nonetheless, this is what their general appearance is like:
Brown to black in color
May have a physical hole in the tooth
Can also appear completely normal and can't be detected without an x-ray
Texture can be soft
Can be located on the front, back, side or in between the teeth
What cavities look like when they're located on different surfaces of teeth
Depending on the surface that the decay is located at, you may or may not be able to see them. They may also look different as well. We will show you be intra-oral photos and x-rays of them of every location that you can possible find tooth decay.
Cavity on side of tooth
Tooth decay that is located on the side of the tooth can either be on the cheek facing side or the tongue facing side. Both of them are considered on the "side" of a tooth.
The cheek facing side is called the "Buccal or facial".
The tongue facing side is called the "Lingual".
If it is an early cavity, the lesion will look white but as it matures, it will turn into a black and brown color. The texture is usually soft if you probe it with an explorer, which is a stainless steel dental instrument.
Here is a picture of what it looks like on the side of the enamel:
This type of cavity typically won't show up on a dental x-ray unless it grows very large. Although if it does progress to a large cavity, it would also involve more than one surface of the tooth. It would most likely involve the top of the tooth as well.
What it looks like:
Black or brown in color
Most likely has a hole in the side of the tooth
Cavity on top of tooth
Tooth decay that is on top of the tooth is located on the chewing surface of teeth. This surface is called the "occlusal" surface.
The color of this lesion usually starts off as a very light brown but as it progresses, it turns into a darker shade of brown. It can also turn into a black color if it stains very badly. The texture is also soft if you probe it with an instrument.
Here is a picture of what it looks like on top of the tooth:
This type of cavity will also not show up on x-rays like the side tooth cavities. They will only appear on the dental x-ray if they grow to a substantial size but usually when that happens, it involves more than one surface.
What it looks like:
Brown to black in color
May have a hole
Cavity in between teeth
These cavities are located where you floss in between the teeth. Due to the fact that they are in between the teeth, you can't actually see them nor can your dentist see them either. The only way your dentist can see them is on an x-ray. You just can't physically see in between your teeth unless you have x-ray vision.
Nonetheless, the only way you can visualize what they look like is AFTER you drill into the teeth during the cavity removal process. What the decay looks like is a different color depending on whether it is in the enamel or the dentin.
Decay in the enamel looks chalky white but it can turn brown for mature cavities.
Decay in the dentin is usually some shade of brown.
Here is a picture of what the decay looks like in between the teeth after drilling into them:
These cavities usually but not always come in pairs meaning that on both teeth that are next to each other. Due to the tendency for them to come in pairs on adjacent teeth, they are sometimes referred to as "kissing cavities".
Here is what an x-ray of cavities in between the teeth look like:
Decay on the root of the tooth
If you look at the x-ray, the two smaller premolar teeth have two dark spots right where you would floss through them. That is where the decay is located and what it looks like on the x-ray.
What it looks like:
Undetectable to the naked eye without x-rays unless the decay is very big.
After you drill into them, they'll look white in the enamel and brown in the dentin.
Cavity in a tooth filling
You may be surprised but you can get a cavity in a tooth filling that already had a cavity filling. We usually call this recurrent decay because it isn't the first time that it happened.
What it looks like is a brownish color inside of a tooth filling. It may or may not feel soft when you probe it depending on if it is located underneath the filling or next to it. You can feel it if it is next to it. If it is underneath of it, you can't fill it until you drill through it.
Here is a picture of what a recurrent cavity looks like:
These lesions usually don't show up on the x-ray because the old filling material will cover it up on the x-ray. These are diagnosed via visual clinical examinations.
What it looks like:
Black to brownish in color
Located inside of an existing restoration
Usually hard to the touch
Cavity on the root
If your gums recede, the root surface can be exposed to bacteria and form a cavity. These lesions are as the name implies, located on the root of your teeth. You can get a cavity anywhere and we mean it!
The appearance of the decay is no different from the other cavities, which means it will be a brownish color. The texture will also be similar as well, which will be soft to the touch.
What it looks like:
Decay on the surface of the root
Usually brown in color
Located near the gumline
May or may not be soft in texture
Cavity on front tooth
Your front teeth are not immune to tooth decay. That means they definitely can get cavities in them. Sometimes they're in the front of the tooth and other times their in the back of it. However, they're most commonly in between adjacent front teeth because people usually don't floss enough!
Here is a picture of what a cavity on the front teeth look like:
What it looks like:
Black to brown in color
Can have a hole
Sometimes undetectable to the naked eye without x-rays
Located on front teeth
Cavity on wisdom tooth
The wisdom teeth are the most prone to getting tooth decay. The reason is because they're the furthest back in your mouth and the most difficult to clean. Most people don't push their toothbrush far back enough so they don't get brushed as often as we'd like.
Due to that reason alone, they get cleaned less than the others and also not as well. That is a recipe for tooth decay! It also doesn't help that they can also be impacted and that just makes them a prime example of a food trap.
What it looks like:
Dark brown to black in color
May be cavitated
Located on wisdom teeth
What cavities look like when they're different sizes
Next, we will show you what the different sizes of cavities look like, a progression from a small cavity to a big cavity. What they look like in the mouth and what they look like on a dental x-ray.
The start of a cavity all begins as a small lesion of tooth decay. Some people refer to these small ones as a stage 1 early cavity since it is the first step.
The very beginning of a cavity will look like a chalky white color. As it progresses and matures, the color will start turning into a light shade of brown and then eventually a dark shade of brown. The texture will also feel soft and mushy to the touch.
Here is what a small cavity looks like:
Due to the small size of the decay, it won't be big enough to show up on an x-ray. You have to wait for it to mature into a much larger cavity before it'll show up.
All untreated small cavities will mature into large ones. These are difficult to miss because of their extensive size. Sometimes they're so big that they occupy more than 50% of the entire tooth surface.
Their color will always be a dark brown or black. The texture is very soft and mushy if you try to touch it. Due to how big it is and how soft it can be, there is often already a big hole in it. This causes a lot of food to get trapped within the hole and that just makes the decay grow even faster.
Here is a picture of very large tooth decay:
As you can see in the picture, the color is very dark and there is an actual hole in the tooth due to how big the decay is.
Here is an x-ray of very large tooth decay:
What it looks like on the x-ray is actually similar to what you see in the mouth. A big dark hole or circle in the tooth. The cavity on this x-ray is on the molar on the top. It is the only one with a big black circle, signifying large decay.
Other signs you may have a cavity
A small cavity may be difficult for you to detect on your own so it may be hard for you to tell if you have a cavity. Only a dentist can definitively diagnose you but sometimes you may be able to feel one. If you notice any of these symptoms below, you may want to be cautious and get it checked out:
Toothache - when you feel pain from eating or maybe even spontaneously.
Sensitivity - if your tooth feels changes to temperature or even to sweets.
Discoloration or holes in your teeth
Swelling or bleeding gums - this could mean that you may have a big hole somewhere
Bad breath - if there are a lot of bacteria secreting acid by processing all of the sweets you eat, the chances of you having a cavity in between your teeth are pretty high.
Hopefully that gives you a good idea of what cavities look and feel like. The most obvious difference is in the color, the decay is usually brown to black in color. The shade of brown is also indicative of how deep the filling will be. The outermost layers that are the most infected and decayed are a very dark brown but as you clean out the filling more, it gets lighter in color and closer to yellow.
The texture of the decay is also different. When you scratch the enamel of a healthy part of the tooth, it will feel solid. If you scratch at the decayed part with a dental tool, it will actually feel soft and sticky. The best analogy would be a termite infested piece of wood. That wood will not be solid but soft and mushy feeling. The same thing occurs in teeth.
Related content: Article about the stages of tooth decay.
How do you treat cavities?
The treatment for it would be cavity fillings where we remove the decay first and then fill it back in with a composite resin, which is a tooth colored filling material. The process is as follows:
Apply numbing gel, followed by the dental numbing shot.
Cavity removal by drilling out the decayed parts.
Tooth conditioner to clean it.
Tooth primer to prepare it for bonding.
Apply the tooth bonding.
Fill it in with a composite resin.
Light cure it to make it hard so that it sets.
Adjust it and polish to make the bite even.
If you want a more in depth guide on cavity fillings, please see our guide.
Otherwise, here are some pictures of the cavity removal processing and then filling it back in:
Can you reverse a cavity?
You may be surprised but it is possible to reverse them but only mild cavities that are still in the enamel. Big ones are usually past the point of reversal. There are two proven ways to reverse tooth decay:
How fluoride can reverse cavities:
Fluoride ions will replace the hydroxyl group on hydroxyapatite to become fluorapatite.
Fluorapatite is more stable, harder, and more acid resistant than hydroxyapatite.
Fluoride can remineralize the decayed parts up to the outermost 30 μm of enamel.
How hydroxyapatite toothpaste can reverse cavities:
Adds an additional layer of hydroxyapatite on top of the tooth enamel. Your tooth is made of the same substance so now you have two layers.
The toothpaste serves as a reservoir of calcium and phosphate ions, which are the building blocks of tooth remineralization.
It also does not preclude the fluoride from working so the underlying enamel layer will get strengthened from residual fluoride in the mouth from drinking sources.
So yes you can reverse them but the cavities won't go away on their own though!
How to prevent cavities
The only way to prevent them from occurring is by limiting the sugar intake, practicing good oral hygiene, and routinely visiting the dentist. As long as you abide by these guidelines, you should be able to keep your teeth healthy and strong.
Here is a full list of strategies that you can implement to reduce the chances of you getting tooth decay:
Brush your teeth at least twice a day for two minutes.
Floss before you go to bed.
Use a mouthwash regularly to reduce bacteria in your mouth.
Stay hydrated by drinking a lot of water. It also helps to wash away residual sugars and acids that may be left on your teeth.
Use a fluoridated toothpaste or a hydroxyapatite toothpaste because they can stop and reverse cavities.
Chewing sugar-free gum with xylitol after meals.
Eliminate or reduce the amount of sugar, carbohydrates, and acidic foods in your diet that may be contributing to decay.
Get a dental check up and cleaning every 6 months.
Depending on whether you live in a community with a fluoridated water supply, you could potentially ask your dentist about fluoride supplements.
Hopefully that answers your question of what a cavity looks like. Perhaps next time, you'll be able to tell if you have a cavity yourself! The most obvious sign to look for is a change in color in your tooth but if you're ever suspicious that you have one, the best thing to do would be to get your dental check up!
Author: Written by Dr David Chen, a restorative dentist in long island city.