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How to Differentiate a Cavity From a Stain

To the untrained eye, a cavity may look similar to a stain but they are completely different dental conditions. The former is a tooth disease while the latter is a cosmetic concern. This means that tooth decay definitively requires treatment but stain removal is purely elective.


A cavity can be differentiated from a stain by a couple of traits:


Here is an overall summary of a cavity vs stain chart:

Trait

Cavity

Stain

Texture

Soft

Hard

Appearance

Brown to black; Possible hole in tooth

Brown, black, orange, red

X-ray

Radiolucent on x-ray

Nothing on x-rays

Symptom

Sensitivity to sweet and cold

No symptoms

Causes

Bacteria

Colored foods

Treatment

Dental filling

Dental cleaning or teeth whitening



Texture of the tooth

A distinctive difference that separates a cavity from a stain is in the texture of the tooth when you probe it with an explorer, which is a sharp metal tool used to detect cavities. A cavity will feel soft and sticky to an explorer while a stain will feel rock solid.


Here is a picture of a cavity:

cavity on side of molar

Here is a picture of a stain:

staining on top of molar

The explanation for the difference in texture is due to the presence of tooth decay in a cavity. The decay will dissolve the tooth structure and slowly eat through it, thereby making it less solid.


An analogy would be termites eating through wood. Wood infested with termites tend to feel soft, while normal wood feels hard. Teeth are the same way, a bacteria and decay infested tooth will feel soft to the touch.



Visual appearance

A tooth stain can be differentiated from decay by the color and also whether or not a hole is present. Aside from that, both will still look like teeth.


A cavity can be brown to black in color. These discolorations can be small dots or they may be a large splotch. Cavities may also sometimes be accompanied by a cavitation, which is a small hole in the tooth. If there is a hole, then it is definitely a cavity and not a stain.


cavity with hole on top of molar


A stain can share color similarities with decay, being brown to black in color. Although the discoloration tends to be a lighter shade of brown or black and not as deep/dark. Stains will also not cause any cavitations.


stain on premolars


What they look like on dental x-rays

If your dentist is unsure about whether or not that tooth has decay or its merely staining, taking an x-ray usually clears it up. Only cavities will show up on x-rays while staining does not. In fact, staining would never ever show up on a dental x-ray so if you see something, then it must be a cavity.


Here is an x-ray of a cavity:

big cavity on molar x-ray

Tooth decay looks radiolucent on the x-ray, which means that it shows up as "dark". Radiopaque structures on the other hand show up as "white" on the x-ray. Objects that are more solid will show up as white while less solid will show up as dark.


Since cavities make the tooth less solid by forming holes in your teeth, they will show up as dark or radiolucent on the x-rays. Therefore, if you see radiolucency in a tooth on an x-ray, it is most definitely a cavity.


Stains on the other hand do not affect the overall structural integrity of the tooth. That is why their texture feels hard to the touch. Consequently, they will not produce any radiolucencies on the tooth for x-rays.



Symptoms

A cavity will have symptoms since it is a dental disease but a stain will be asymptomatic because it is merely a cosmetic condition.


Symptoms of a cavity:

  • Sensitive to sweet

  • Sensitive to cold or hot

  • Possible pain when chewing

  • Food gets trapped in the tooth hole


Since tooth stains are not a dental disease, there are no symptoms associated with it. There will be no sensitivity nor will there be any pain for teeth with stains. However, it may bother you due to its cosmetic appearance but that is all psychological and not physical.


tea staining on molar


Causes

Another important distinction is that cavities are caused by bacteria while stains are caused by foods and liquids that have color in them.


Causes of cavities

The discoloration from tooth decay is a result of bacteria processing sugar and producing acid that eats through your tooth. The very beginning stages of tooth decay starts with enamel demineralization, where the tooth looks like an opaque chalky white. As the cavity progresses, that chalky white starts to turn brown and eventually black if the decay gets big enough.


Causes of tooth staining

Staining on your teeth are caused by foods and drinks that you consume, which have coloring in them. As a general rule of thumb, if it can stain your white carpet, it will stain your pearly white teeth.


However the most notorious for causing teeth staining are these:

  • Red wine

  • Coffee

  • Tea

  • Tobacco and cigarettes

  • Sodas

The interesting thing is that depending on the food coloring, it may stain your tooth the same color. As an example, if you eat a lot of orange creamsicles or cheetos, you may notice your teeth turn orange or have orange plaque. The plaque and tartar in your mouth can also pick up colors as well!


The stains can be on the surface or it could become embedded into your teeth. The surface ones are called extrinsic stains while the embedded ones are called intrinsic stains. The extrinsic type can be removed by brushing and dental cleanings but the intrinsic type will require whitening.



Treatment

Treatment for both cavities and teeth staining will require the help of a dental professional. The cavity treatment will be much more invasive due to the fact that the decay needs to be drilled out, which makes it irreversible. The staining treatment will be more conservative and all of the procedures are reversible.


Cavity treatment

Depending on the size of the cavity, treatment may differ but all of them will require a visit to the dentist.

  • Small cavity. Typically for tooth decay that is still small, a simple cavity filling will be sufficient. Your dentist needs to remove the decay and then fill it back in with a tooth colored filling material. The whole process should take no less than an hour and one visit.

  • Medium sized cavity. Untreated cavities will get bigger and medium sized ones may require either a large dental filling or a crown. If you need a crown, it would take a total of two visits because the first visit is for preparing the tooth and taking a mold of it. Then the mold gets sent to the dental laboratory to have it fabricated. Once it returns, your dentist will try in the crown and glue it in permanently if it fits.

  • Large cavity. Very large cavities will need either a root canal and crown or an extraction. It all depends on how severe the decay is, which dictates whether the tooth can be saved or not.

In order to prevent cavities from returning, you must be diligent with your oral hygiene routine and also minimize sugar intake.

  • Oral hygiene. You must brush for at least 2 minutes twice a day. Then you have to floss right before going to bed. If you're up for more, you can use a mouthwash to help remove any residual plaque that the brushing and flossing may have missed. This routine needs to be every single day without fail.

  • Minimize sugar. The best thing to do would be to eliminate sugar and carbohydrates from your diet in order to never get a cavity again. However that may be difficult for most people so the recommendation would be to minimize the amount of sugar that you consume. The reason is because bacteria require sugar to produce tooth decay so if you simply deprive them of it, you wouldn't get cavities.



Stain treatment

Stains on teeth are merely a cosmetic condition but most people will try their best to have them removed because it improves their looks and self-esteem. The treatment involves teeth whitening and a dental cleaning.

  • Dental cleaning. Since plaque and tartar can incorporate a lot of staining, it would be prudent to have them removed professionally by a dentist or hygienist. Plaque you can remove at home by brushing but once it calcifies into tartar, only a dentist can do it. This is why it is important to go in for your teeth cleanings every 6 months to get rid of the tartar on teeth.

  • Teeth whitening. If your tooth is still discolored even after the cleaning, you will need to have them whitened because the stains are deeply embedded into your enamel. The only way to remove them is to oxidize the stains via teeth whitening that either contain hydrogen peroxide or carabmide peroxide. This treatment comes in a lot of variations and can be done with take home trays or in-office.

In order to prevent stains from coming back, you should try your best to use a whitening toothpaste, at home teeth whitening, and also minimize staining foods.

  • Minimize staining foodWhitening toothpaste. Most whitening toothpastes help whiten your teeth by mechanically removing plaque and surface stains. However, there are some toothpastes, which contain whitening material in them, that make it even more effect. There are two toothpastes which do this and they are the Colgate Optic White and the Supersmile.

  • At home teeth whitening. The simplest at home whitening product would be the whitening strips that you can purchase at the pharmacy. The most popular one is the Crest 3D whitestrips. This can help you remove deeply embedded intrinsic stains.

  • Minimize staining food. If you simply avoided all of the staining foods like red wine, coffee, and tea your teeth wouldn't pick up any stains! However most people are unable to live without their cup of coffee in the morning, so the next best thing to do would be to minimize the intake of these beverages. What also helps is if you rinse your mouth out with water after drinking them. That prevents the residue from sticking onto your enamel.




Takeaway

You may have a better idea of how to tell a cavity apart from a stain but ultimately only a dentist can give a definitive diagnosis. Even if you do master the art of telling them apart, you're unable to remove nor treat cavities so you'll still need a dentist! Therefore it is important to go in for your 6 month dental check ups.



Author: Written by Dr David Chen, a long island city dentist.


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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!