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.
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.
This is a picture of what the pre-cavity looks like on a molar. For the molar below, it presents itself as a white streak across the enamel near the gumline.
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.
The color of small cavities
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.
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:
Administer local anesthesia to numb the tooth.
Drill out the decayed part of the tooth.
Apply conditioner, primer, and bond to the tooth.
Restore tooth with a tooth filling composite resin.
Light cure it to harden it and make it set.
Adjust the bite.
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.
Here is a picture of a mid sized cavity that is brown in color on the chewing surface of a premolar tooth. If you compare it to its smaller counterpart, the brown is much darker shade. It basically means that the decay has been maturing.
Just to convince you further, here is another clinical photo of a medium sized cavity in a molar. The size of these lesions are larger and darker than the smaller sized decay.
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:
Administer local anesthetic - Lidocaine, to numb the tooth.
Clean out the decay with a high speed drill.
Apply a conditioner, primer, and bonding to the tooth.
Place a liner at the base of the cavity to help protect the nerve.
Fill the tooth in with a composite resin.
Light cure the tooth to make it hard.
Adjust the bite so that it feels even.
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!
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.
Here is a picture of a very large cavity on the chewing surface of a molar. It is a dark brown to black color. It is as bad as it looks!
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!
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.