Of course the dentin can be whitened because teeth whitening products whiten the entire tooth and not just the enamel. If these products only affected the enamel, they would’ve been called enamel whitening products instead of teeth whitening products. They’re called the latter because all teeth whitening will change the color of both the enamel and the dentin!
Does that make sense? Well, in case you still don’t believe us, we’ll give you a couple of hard evidence via studies and actual dental procedures that prove the dentin can be whitened.
Scientific studies that prove dentin can be whitened
There was a study in the Journal of Endodontics, which measured the whitening effects on enamel and dentin. The bleaching material was applied to the external surfaces and then they measured the color change of the enamel and dentin. What they found was that the enamel had the greatest change in color but the dentin also changed as well, albeit less than the enamel.
Our critique about that particular study was that the whitening material was placed on the exterior of the tooth, which is in closest contact to the enamel. That is the reason why the enamel shade changed more than the dentin. If the researchers placed the whitening material from within the tooth making it closer to the dentin layer, the results would’ve been much different!
There was another study by Clinical Oral Investigations which measured the whitening effects on enamel and subsurface dentin. They found that the color change in subsurface dentin had a big influence on the overall color of the teeth. In other words, if your product is able to whiten the dentin more effectively, you’ll probably get a better overall cosmetic result.
Internal teeth whitening or dentin whitening
Unbeknownst to most people, there is an actual dental procedure called internal teeth whitening. This is completely different from what the majority of the populace is familiar with, which is external teeth whitening.
The kind of teeth whitening that everyone knows and talks about is the external whitening. All of these products place the bleaching gel on the outer surface of your teeth. How they work is that they whiten from the outside and inwards. Unfortunately, the gel does not penetrate through the entire tooth because most of the effects affect the outermost enamel layer.
This is in contrast to internal teeth whitening where your dentist places the whitening material inside of your tooth. This type of whitening whitens the tooth from the inside out.
The internal whitening is a treatment option that is ONLY available for dead teeth which have turned grey and have had a root canal before. The requirement is that the tooth needs to have had a root canal. The reason is because your dentist drills a hole into the back of the tooth and then literally places the whitening material inside of the nerve chamber of the tooth.
The whitening material is then allowed to whiten the tooth from the inside first and then it travels outwards. Here is a study from the International Journal of Endodontics which references this procedure, which is also called “the walking bleach technique”.
It is not a novel procedure because it has been around for a long time. There are plenty of studies on it already which we’ll link to below as further evidence.
Not everyone is aware of this internal whitening procedure, which specifically attempts to whiten grey teeth which are dead because not everyone has a dead tooth. The reason that these teeth start turning grey is because they actually darken from the inside out and not from the outside in. This is also why external teeth whitening does not work very well on dead teeth. Dead teeth require internal whitening treatment, in other words they require dentin whitening more so than enamel whitening.
Before and after teeth whitening results
The picture above is of some of the KoR whitening before and after results. In one of the examples, you can see one where one of the front teeth is very yellow. That is what the color of a dead tooth looks like. KoR is very impressive in that it can externally whiten a tooth like that.
However, it can still benefit from some internal whitening because you can still tell that it is a tad more yellow than the adjacent teeth. If they get the internal treatment, they can probably get it to match the surrounding teeth’s color.
Do whitening strips whiten dentin?
The strips can whiten dentin but it won’t be as effective as professional in-office whitening. The reason is because the concentration for OTC products are typically less than professional in-office strength ones.
The whitening strips will mainly affect the outer enamel layer the most because that is what is in contact with the strips. Some of the gel may penetrate deeper into the dentin layer and may potentially whiten the dentin a little bit.
They can be more effective for whitening dentin if the strips are able to come into direct contact with the dentin such as if you had thin enamel. If your layer of enamel is thinner than other people, the material would have a shorter distance and easier time for it to reach the dentin layer. Therefore it should have a greater effect on the dentin color.
The last situation where it can effectively whiten it is if you had exposed dentin. Perhaps your enamel eroded away from drinking too many acidic drinks and now your dentin is exposed. In this situation, the strips would have direct contact with the layer of dentin. This would probably be the most effective time that they’ll whiten them.
The unfortunate side effect of whitening exposed dentin is that it will be extremely sensitive afterwards. The reason is because the enamel layer is actually not alive and does not contain any nerves. The dentin layer however does contain a lot more nerve endings. The whitening material being in direct contact with the dentin also means that it’ll be in direct contact with the nerve endings.
In other words, expect a lot of post-operative sensitivity if you whiten your teeth with exposed dentin or thin enamel.
Takeaway
The dentin can be whitened because all teeth whitening products whiten the entire tooth and not just the enamel. The only reason that the dentin doesn’t whiten as much as the enamel is that the whitening material tends to be in contact with the enamel directly and not the dentin. If you’re able to get the gel in contact with the dentin, you’ll notice them whiten a lot more.
Two situations where you’d be able to whiten the dentin more is if you had thin enamel or exposed dentin. Both of these create situations where you can get the whitening material closer to where the dentin is. Of course, you’ll feel a lot more sensitivity afterwards though!