Having cavities does not prevent you from getting your teeth whitened because it does not physically limit you from doing so but it isn't recommended.
Despite tooth decay not disqualifying you from teeth whitening, there are quite a few reasons why you may not want to do it even though you can.
The black decayed parts will remain even after whitening.
You may experience greater teeth sensitivity.
Are you really able to whiten decayed teeth?
Having cavities doesn't disqualify you from undergoing teeth whitening treatment. The reason is because it does not physically prevent nor limit you from doing so. You can still whiten them because the whitening gel doesn't care if there is decay or not.
In order to understand why this is the case you should think about how the whitening gel works. Depending on the whitening system that you're using, the pen, trays, or strips, all of the whitening material is placed on the front surfaces of your teeth. Just because the tooth is decayed it doesn't stop you from still putting the gel on the teeth.
The tooth fairy isn't standing right next to you, telling you that you can't do it.
Nonetheless, even though you can do this it is not recommended to do so by dentists. We'll give you a couple of compelling reasons as to why you may want to have the cavities treated first before you get the teeth whiter.
Whitening decayed teeth is not recommended
Yes, you can do it but you probably don't want to because there are some unintended side effects.
Whitening doesn't get rid of cavity. Carious tooth structure is often black to brown in color and the whitening gel will not change its color.
Decayed teeth are more sensitive while whitening. A cavity is a hole in your tooth and putting bleaching gel on it will give it a direct path to your tooth nerve. That can cause immense teeth sensitivity.
Tooth decay will not go away despite whitening
In case you didn't know, the color of cavities is typically in the brown to black color spectrum.
Small cavities that are starting to develop will present themselves as a light brown color. Larger and more mature cavities will be a dark brown to black color. There was a study done on the shades of decay, which found a correlation between the darkness of the decay with the extent and severity of it.
The teeth whitening process will not get rid of the cavities because the only way to do that is by getting a cavity filling with your dentist. The significance of that is even if you whiten your teeth everyday for an entire year, it will not get rid of the black and brown cavities. This makes it counterproductive to your goal of having white teeth.
Sure your teeth may get a little lighter from the treatment but if you leave the cavities untreated, it will start to grow. The color will start turning black a lot faster than you can even whiten them. Hopefully that is an incentive for you to get your tooth decay addressed prior to starting the bleaching process.
Greater teeth sensitivity
Cavities may feel sensitive to hot, cold, sweet, acidic, and spicy foods. That means if you have decay in your teeth they will already be sensitive before even starting any whitening treatment.
According to the American Dental Association (ADA), sensitivity and gingival irritation are two known adverse effects from whitening.
In other words, if you start whitening treatment while your teeth are already sensitive, it will only make it worse. What will most likely happen is that you'll have an exaggerated sensitivity response to the whitening gel. Your teeth will feel a lot more sensitive during the treatment when compared to someone who does not have any cavities.
Not that you can't complete the treatment but the entire process will just be more painful and a lot less pleasant. Perhaps the discomfort may even be enough to stop you from finishing the entire treatment since the teeth are so sensitive. That's certainly something to keep in mind because we do have some patients who don't have cavities but have to stop in the middle of treatment due to sensitivity. The chances of that happening may increase if you leave the cavities untreated.
Why cavities cause sensitivity
The literal definition of a cavity is a hole and a tooth cavity means that there is a hole in the tooth. Having a hole in your tooth will make your teeth sensitive because beyond the dentin layer is the pulp, which houses the tooth nerve. If you have a direct tunnel that leads from your mouth to the nerves, the pulp will get irritated.
The whitening gels consist of hydrogen peroxide or a derivative of it. What that means is it is a very acidic material. Now imagine letting this gel go straight through the cavity and come into direct contact with your tooth nerve. That makes for a very unpleasant experience doesn't it?
Even without a cavity, the hydrogen peroxide naturally tries to diffuse through the tooth and oxidize all of the stains that it encounters. Letting the peroxide oxidize your tooth nerve is definitely a painful experience.
Related content: If you wanted to read more about how hydrogen peroxide whitens your teeth, we have an entire article dedicated to it!
Despite cavities not precluding you from whitening your teeth, it is typically not recommended to do so because there are side effects.
Side effects of whitening with cavities:
Your teeth may become extra sensitive while you're whitening with untreated decay.
The bleaching will not get rid of the cavity meaning the decayed parts will still look black/brown in color.
It just doesn't make a lot of sense to try to "whiten" your teeth when you're purposefully leaving brown cavities in your teeth. Seems counterproductive to your goal of improving the color of your teeth doesn't it?
Basically what we're trying to say is you should get the cavities treated prior to beginning whitening treatment. This is why we recommend all of our new patients to schedule a dental check up prior to getting the whitening.