Sensitive toothpaste does work in desensitizing your teeth but it's effects are temporary and require consistent reapplication in order to maintain its effect. There are certain factors which increase/decrease its efficacy and it may be due to these that make you think it isn't working.
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Sensitive toothpaste is not a permanent solution
Unfortunately sensitivity toothpaste is NOT a permanent solution for sensitive teeth. That means a single application of brushing your teeth with it will not make the symptoms go away.
What the sensitive toothpaste does instead is help you manage teeth sensitivity when you use it consistently over a long period of time. The anti-sensitivity effect only works while you're using it and if you keep using it. If you stop using it, it will stop working.
In other words, it is similar to a prison life sentence in that you need to use this toothpaste for the rest of your life. That is the only way you'll get relief from your sensitive teeth.
Why does it only work if you keep using it?
There are three different desensitizing agents that toothpastes can utilize and they all work slightly differently.
Potassium nitrate - renders the tooth nerve unexcitable.
Stannous fluoride - occludes open dentinal tubules.
Nano-hydroxyapatite - occludes open dentinal tubules.
Patients with chronic sensitivity will have wide open dentinal tubules or enlarged ones. That means stimuli can easily enter into the tubules and stimulate the tooth nerve.
The stannous fluoride and nano-hydroxyapatite desensitizes your teeth by plugging all of the open tubules. That effectively prevents stimuli from triggering symptoms.
The potassium nitrate desensitizes your teeth by preventing the nerve from sending pain signals. This desensitizer leaves the tubules open but just makes it so that the nerve can't fire signals.
Either of the methods will work but unfortunately, these desensitizers need to be constantly replenished. As we eat sweet and acidic foods, they will dissolve or wash away the desensitizing agents. When you brush with the toothpaste, it will replenish the lost desensitizers. That is why you need to keep using it for it to work!
Essentially it is a constant battle between applying the desensitizing agent and having it dissolved whenever we eat. The net effect would be whichever one you do more of and that is why we call it managing sensitivity and not curing it.
If you constantly eat sweets or acidic foods, the sensitive toothpaste may not be able to keep up.
However if you decrease the consumption of those types of foods and brush more diligently, you may come out with a net anti-sensitivity effect.
What makes sensitive toothpaste less effective
The sensitive toothpaste does work but depending on your personal habits, it may not be as effective as it could be. You're essentially setting yourself up for failure if you don't brush long enough and also if you eat too many acidic foods. Both of these habits will make the toothpaste less efficacious.
Insufficient brushing time
All of the desensitizing agents in the toothpaste work via a topical effect. The more time the desensitizer is in contact with your tooth, the better it will work. The less time it remains on your tooth, the less effective it will be.
It is very similar to how pain patches adhere to your skin so that it continually releases the numbing agent. The longer you keep it on the better it works. The same situation applies to your teeth in that you want it to be on your teeth for as long as possible.
The recommended brushing time is at least two minutes twice a day according to the ADA. That should give you ample time for the desensitizer to penetrate the tooth and work its magic. That statistic is also how the toothpaste manufacturers designed their product to work.
Unfortunately, the reality is different because the average brushing time is only 45 seconds. According to multiple surveys, people know that they're suppose to brush for 2 minutes but when they actually brush it ends up being 45 seconds total. That is a far cry from how long they're supposed to be brushing.
Obliviously the insufficient brushing time will not only leave more plaque on your teeth but also deprive the desensitizers from giving its full effect. Basically, by not brushing for at least 2 minutes you're not allowing the desensitizing agent to do its job properly. The end result is persistent sensitive teeth! You're shooting yourself in the foot when you don't spend enough time brushing.
Diet full of sweet and acidic foods
You can be diligently brushing your teeth with sensitivity toothpaste twice a day for at least 2 minutes but if you binge eat low pH food, your teeth will still be sensitive. Excessive amounts of sweet or acidic foods will constantly attack your teeth with acid. All of that acid will dissolve all of the desensitizers on your teeth, thus bringing you back to square one of where you started.
Remember that the net effect is dependent upon if you do more desensitizing activity or sensitizing ones. Excessive consumption of low pH food will tilt you towards sensitizing effects and make it worse.
Therefore if you have very sensitive teeth you may want to consider minimizing or even avoiding these irritating foods. You're really not helping yourself
What makes sensitive toothpaste work better
Contrary to habits that can make the sensitive toothpaste less effective, there are habits that can make it work better. Doing these will make the anti-sensitivity go further and can potentially give you the relief that you've been looking for.
Brushing more frequently
Similar to how not brushing enough can lead to sensitivity, brushing more frequently can help alleviate it. At the bare minimum you should brush for two minutes at least twice a day.
However if you can brush more than twice a day, you can give an extra boost for desensitizing your teeth. Reason being you're replenishing more of the dissolved desensitizing agent whenever you're doing so.
Think about the process of desensitizing and sensitizing.
Every time you brush, you desensitize the teeth.
Every time you eat, you re-sensitize the teeth due to the acid attacks.
You certainly eat more frequently than you brush so net effect is usually towards sensitizing.
Therefore if you're able to brush after every meal, you'll be pleasantly surprised by how much the symptoms improve! You should give it a try.
Applying toothpaste for a longer period of time
To reiterate, all of these toothpastes work topically which means they exert their effect while they're in contact with the enamel. The longer you allow it to stay on the teeth, the more of the effect you will receive. Consequently the opposite is also true in that if you only brush for a short amount of time, you'll have a lesser effect.
Therefore it can be extremely helpful in alleviating some of the symptoms if you simply brush for longer than the 2 minutes. Why don't you try brushing for three minutes instead of two. That extra minute could make a world of difference in making your teeth less sensitive.
Just to give you an additional reason to brush longer, studies have actually shown that 3 minutes is better than 2.
2 minutes of brushing removed 26% more plaque than 45 seconds of brushing.
3 minutes of brushing removed 55% more plaque than 45 seconds of brushing.
That extra minute will remove more plaque but in our case, it'll probably help decrease some of that hypersensitivity even more!
Last but not least according to Dr Kurthy from KoR Whitening, extreme teeth sensitivity after bleaching could benefit from extended contact with sensitivity toothpaste. He recommends that you place the desensitizing toothpaste in the whitening trays and wear it for 30-45 minutes. Reason being to allow the toothpaste an extended period of time to alleviate the symptoms!
Minimizing sweets and acidic foods in diet
Excessive consumption of acidic or sweet foods can undo all of your desensitizing efforts. If you're constantly drinking wine, coffee, or sodas, no amount of sensitive toothpaste can help you.
If the sensitivity is really decreasing the quality of your life and you're doing everything that you can, you may want to consider minimizing these irritating foods. That may be the only option left for you.
How long does it take for sensitive toothpaste to work?
Sensitive toothpastes may take anywhere from 1-14 days before it starts showing a decrease in sensitivity. How long it takes to work depends on the desensitizing agent. It appears that those which occlude the dentinal tubules work faster than the nerve inactivators.
Potassium nitrate - Studies have shown that it may take up to 2 weeks for you to see results. The symptoms continued to improve up to the 12 week mark.
Stannous fluoride - Studies have shown that a desensitizing effect was present after a single day of use.
Nano-hydroxyapatite - Studies have shown that symptoms were reduced after using for a day.
Ultimately the dentinal occlusion agents such as stannous fluoride and nano-hydroxyapatite seem to wear quicker. The nerve desensitizing agent such as potassium nitrate seems to take longer for it to work, however it keeps improving up to the 3 month mark.
Alternative to using sensitive toothpaste
Anti-sensitivity toothpastes are a form of OTC product which you can use at home to help decreasing some of the discomfort from your teeth.
The only other alternatives to making your teeth less sensitive would require a trip to the dentist. These all require dental procedures and are much more invasive.
Dental bonding. A composite bonding could be placed over the surfaces of your teeth or roots that are exposed.
Veneers. The bondings don't last forever but the porcelain veneers have better longevity. Of course this procedure is more costly than composite bonding.
Crowns. This is a full coverage restoration that is similar to the veneer except it is more aggressive. Typically it is reserved for teeth that are more severely affected.
Gum grafts. A lot of sensitivity comes from gum recession or exposed root surfaces. Instead of placing a restoration, you can see a gum specialist to regrow the gums.
All of these alternatives are more invasive and more costly than sensitive toothpaste. The decision is yours to make.
Takeaway
The research shows that sensitive toothpaste does work and there are two different mechanisms in how they do. The only reasons why they wouldn't work is actually due to your own personal habits. Some of the things you do can make it worse but they can also make it better as well.
Habits that make the toothpaste work less effectively:
Not brushing for at least two minutes.
Eat too much irritating foods.
Habits that make the toothpaste work more effectively:
Brushing more frequently than twice a day.
Brushing for longer than two minutes.
Eating less irritating foods.
Overall, the main determinant of whether or not the toothpaste works is a simple math formula. Are you partaking in net desensitizing activities or sensitizing activities. Depending on your answer, you the toothpaste could be working or it could not be.
Last but not least, we do have a guide on how to stop sensitive teeth pain immediately.
