Teeth whitening strips - Common side effects and how to manage them.

- Thermal sensitivity. / Gum irritation. / Treatment and remedies. / Ways to prevent and control side effects.

Dealing with side effects caused by whitening strips.

a) Common problems.

The two most common side effects people experience when using a whitening strip product (like Crest Whitestrips®) are: 1) Tooth sensitivity  and  2) Gum irritation. This page outlines remedies for both of these complications.

b) Side effect avoidance.

You can minimize your risk for side effects, or get them under control more quickly once they start to appear, by following some basic guidelines. The lower portion of this page explains how.

1) Tooth sensitivity.

Studies suggest that between 1/3 and 1/2 of all people who use Crest Whitestrips® will experience some degree of tooth sensitivity. This is on par with that level typically reported for other peroxide-based whitening methods.

a) Why does it occur?

The cause of the sensitivity is no doubt multifactorial. But one major aspect has to do with irritation (inflammation) of the tooth's nerve by the strip's peroxide whitener.

In general, the more concentrated the whitener, the more likely it is that this effect will occur. (So, if you're searching for the "strongest" or "quickest working" strip, you may be setting yourself up for a fall.)

b) What's the pain like?

In most cases, the sensitivity that's noticed is a heightened reaction of your teeth to hot and cold items, such as foods and beverages. Dentists call this "thermal sensitivity."

How much pain can you expect?

Since strips whitening typically involves the use of a relatively low concentration whitener, the sensitivity they cause usually comes on gradually. It may increase with each treatment, or just be noticeable for those first few hours following a bleaching session.

Since the sensitivity is usually relatively minor, and setting it off fairly easy to avoid, it typically doesn't cause great disruption in a person's life. Or even interfere with their bleaching schedule.

c) Tooth sensitivity - Remedies.

1) Some improvement should occur naturally.

In the majority of cases, a person should notice that their thermal sensitivity begins to fade, a little each day, once they have completed their bleaching treatments.

Performing whitening sessions less frequently or using a lower concentration product (such as Whitestrips® Gentle Routine) can help to speed this process along. - More information.

2) Try using desensitizing toothpaste.

You may be able to control the level of sensitivity that you experience by using an over-the-counter anti-sensitivity (desensitizing) toothpaste.

Toothpaste 'for sensitive teeth' can often cure tooth sensitivity side effects caused by teeth whitening strips.

Using desensitizing toothpaste, before or after problems occur, can help.

Many manufacturers make an anti-sensitivity version of their regular paste. These products are often labeled with the phrase "toothpaste for sensitive teeth." Their active ingredient is frequently potassium nitrate or fluoride.

(Related page: The best toothpastes for treating tooth sensitivity.)

Relief may take some time. - The idea is that you use the toothpaste in place of your regular one, for some days and weeks, as it gradually produces its effect.

(Prescription-strength fluoride toothpaste or gel prescribed or dispensed by your dentist can also be used in a similar fashion.)

3) Preventing tooth sensitivity.

As a way of helping their patients reduce their risk for experiencing thermal irritation, many dentists recommend that they begin using a desensitizing toothpaste two weeks prior to initiating the use of their whitening strips.

2) Gum irritation.

Studies suggest that between 1/3 and 1/2 of all people who use Whitestrips® will notice some degree of gum tissue irritation.

a) Why does it occur?

Gum irritation is caused by the caustic nature of the peroxide found in a strip's whitener. In general, the higher its concentration, the greater the likelihood that this side effect will be noticed. (Once again, a reason why the "strongest" or "quickest working" type of strip doesn't likely make the best choice.)

Teeth-whitening strips can cause gum irritation.

The cause of whitening strip gum irritation.

1) The fit of the strips is part of the problem.

Unlike the scalloped shape of a person's gum line, the edges of a whitening strip are relatively straight.

And this means that when a strip is positioned over the user's teeth, some of its full-strength whitener will be in direct contact with their gums.

2) Residual whitener can be the cause too.

Gum irritation can also result from deposits of whitener that are left behind after a whitening strip has been removed.

For this reason, you should always rinse, wipe and/or brush your teeth and surrounding gum tissue after every bleaching treatment. Be sure to wash your hands and toothbrush off afterward.

b) How much discomfort can you expect?

In most cases, the level of gum irritation that a person experiences is just mild. It usually doesn't interfere with their daily activities, or even their bleaching schedule.

c) Remedies for gum irritation.

In the typical case, whitening strip gum irritation will gradually disappear over the next few days after the person's bleaching treatments have been completed. Performing sessions less frequently or using a lower concentration strip product (Crest Whitestrips® Gentle Routine) can help to keep this side effect in check. - More information.

d) The whitener may irritate your fingers.

Besides just your gums, a strip's whitener can also irritate your skin. We discuss this phenomenon in greater detail here.

3) Guidelines for managing side effects.

a) If you notice side effects, stop your whitening treatments.

If side effects start to show up, it only makes sense to stop performing whitening treatments (right now, immediately).

There's absolutely no reason not to.

Bleaching teeth with peroxide is simply a function of whitener concentration and total treatment time (session length X number of sessions).

Interrupting the process for a few days, as you evaluate your side effects and allow them to subside, will not compromise your results (assuming that at some point you are finally able to finish using all of your strips).

b) Re-evaluate your whitening approach.

Once your side effects have subsided, you'll need to make a decision. Should you resume your treatments, or have the side effects you've experienced put you off on the whole idea of whitening your teeth.

If you do decide to continue on, you now have experience with what doesn't work. So, what you need to do is come up with a plan that can help to reduce the chances that your side effects will return.

1) Try using your whitening strips less frequently.

One plan that can be successful is to continue on with the use of your strips but perform treatment sessions less frequently.

You'll simply have to experiment to see what regimen works best. For example, if wearing them every other day still triggers side effects, try every 3rd day. Or whiten on consecutive days until symptoms start to occur, and then back off on treatments for a while.

And don't worry, as we discussed above, performing sessions less frequently won't interfere with the bleaching process, it will only slow it down. Assuming you still use all of your strips, you'll reach the same lightening endpoint.

2) Try using a lower-concentration strip.

Another solution involves using strips that are coated with a lower concentration whitener. For example, instead of using one of Crest®'s standard 10% hydrogen peroxide strips, try using their 6% one (Crest Whitestrips® Gentle Routine).

Different than above however, by using a lower concentration strip your total exposure to the whitening agent will likely be less. If so, you'll achieve less whitening success.

3) Which approach is better?

To get a relative idea of which approach might be best for you, simply do some calculations. For example:

  • Crest Whitestrips® Professional Effects (10% hydrogen peroxide whitener, 30 minute application, 20 sessions) - 10 hours of total exposure of a 10% product.
  • Crest Whitestrips® Gentle Routine (6% hydrogen peroxide whitener, 5 minute application, 28 sessions) - 2.3 hours of total exposure of a (roughly half as strong) 6% product.

Clearly these two products couldn't possibly be expected to produce the same whitening outcome. In the case where side effects are a problem for you:

  • If your teeth just need a little improvement, the Whitestrips® Gentle Routine product would probably make a good choice.
  • If your teeth need a lot of improvement, you might either use Whitestrips® Professional Effects but spread out over a longer time frame. Or consider ultimately using more than one box of the Gentle Routine strips.

4) Gauging your risk for side effects.

Start out slowly.

A smart way to test your potential for experiencing side effects is simply to ease into the use of your strips.

For example, if their directions recommend daily treatments, do an initial one and then skip a day. If you notice even a hint of side effects, continue on with this routine (or less) as you figure out what degree of problems you're going to experience.

Faster and whiter isn't better.

If you're trying out teeth whitening strips for the first time, choosing a product that boasts that it gives faster and brighter results may not make the best choice, at least in terms of avoiding side effects.

These types of products tend to be ones that have a higher concentration whitener, or are intended to be worn for extended time periods (possibly even an hour or more). Neither of these characteristics lend themselves to preventing side effects. When choosing, just look for a standard "introductory" type product made by a well known manufacturer.

5) Safety concerns.

Whitening strips provide a consistent, controlled dosing of whitener.

Whitening strips are unique in the world of tooth-bleaching products in the sense that the dosing of whitener, per treatment, is extremely consistent. This is because it's applied by the manufacturer when they are made.

And in light of the unsupervised nature of the use of over-the-counter products, and concerns about safety, side effects and effectiveness, this is a nice feature.

In contrast, with tray systems the amount of whitener that's used for each individual treatment can vary by quite a lot (because the user applies it).

And because of this difference in the way the bleaching agent is dispensed, it's been calculated that treatment utilizing a 6% hydrogen peroxide strip (comparable to how today 10% strips are used) involves one-half to one-fifth as much total peroxide as a comparable treatment using a tray-based system with a 10% carbamide peroxide bleaching gel. (Both systems should provide similar whitening results.)


This page details the safety concerns for the peroxide whiteners used with tray technique. Since the whitening science for them is the same as with strips, you should read it.

As you do, keep in mind that, per the information above, the amount of exposure you have to peroxide when using whitening strips is typically less.



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I found this very helpful I'm glad you had this for me to read I was starting to get very concerned with my irritation in my gums after using this product. Now I will continue to use it every other day. thank you

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