Teeth-whitening Strips - What are they? / How effective are they?
The basics -
Teeth-whitening strips are a relatively new innovation in the world of over-the-counter tooth-bleaching products.
Proctor & Gamble introduced their Crest Whitestrips line in 2000. Since then, a number of companies (Sheer White!™) have developed their own similar products.
[Crest Whitestrips is a registered trademark of the Proctor & Gamble Company.]
Whitening strips offer a simpler at-home alternative.
The idea associated with whitening strips is simply this. They provide a way for a person to perform comparatively effective whitening treatments on their own, at home, without the use of messy trays and gels.
What are the strips made out of?
Teeth-whitening strips are clear, thin, flexible pieces of plastic (polyethylene) that have been coated on one side with a film of hydrogen peroxide bleaching agent.
This type of design creates some advantages.
Here are some of the advantages of a "strip" design.
- As compared to all other (reasonably effective) at-home methods, this is probably the simplest, least-messy way to whiten your teeth.
- Since the manufacturer applies the whitener, the dosing you're exposed to is very controlled and consistent. This helps to insure predictable whitening results and to minimize the risk for side effects.
- Because only one side of the strip is coated with whitener, it acts as a barrier that helps to prevent whitener contact with soft tissues and to minimize its dilution by saliva. This helps to increase effectiveness and decrease the potential for side effects.
What type of whitener is used?
Teeth-whitening strips are typically coated with a hydrogen peroxide-based whitener. For example, Whitestrips Classic is coated with a 6% hydrogen-peroxide whitener. Other products and brands have higher concentrations, 9 to 10% is common, even 14% is available. (We discuss the issue of whitener concentration below.)
How does the whitener work?
Whitening-strip science involves a process where the hydrogen-peroxide component of the whitener breaks down into molecules called "free radicals." These very reactive agents cleave up the complex molecules found in a tooth's enamel that have caused its staining.
In general, peroxide teeth whitening involves thin-film chemistry. This simply means that tooth bleaching doesn't require a lot of peroxide but instead just enough to cover over the surface of the teeth being lightened.
Whitening-strips technique simply takes this concept to an extreme. The coating of whitener that is applied to them is roughly .2 millimeters thick. (The thickness of a piece of paper generally measures about .1 millimeters.)
How are whitening strips used?
Teeth whitening strips are easy to use (instructions). A strip is just positioned over your teeth and then gently pressed into place. At the end of your session, the strip is simply pealed off and discarded.
How long are strips worn?
Crest Whitestrips are worn for 30 minutes a day, twice a day. Other products are worn just once a day. The total number of days of treatment varies with the particular product that's been purchased.
Some examples of treatment durations.
Whitening strips that have a 6% hydrogen-peroxide whitener (Whitestrips Classic) are typically worn over a course of 14 days. Those coated with a 10% whitener (Whitestrips Premium and Premium Plus) are intended for a treatment period of 7 days. Other products will have their own specific directions.
Why these differences in treatment time frames?
Dental research has shown that the whitening effect produced by peroxide tooth whiteners is simply a function of concentration and treatment time.
In the example above, the (roughly) half-as-strong strips are used for twice as many days. Both products end up delivering about the same total dose of hydrogen peroxide. And for this reason can both be expected to produce essentially the same level of whitening results.
It's ok to quit early.
Of course, if a person has already achieved the whitening results they want before they've used the entire contents of their whitening-strips kit, or if the side effects they experience become unmanageable, treatments may be terminated at any time.
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How effective are teeth whitening strips?
You can expect whitening strips that have a 6% hydrogen-peroxide whitener (the basic type of strip, like Crest Whitestrips Classic) to be about as effective as using a tray-based system that utilizes a 10% carbamide-peroxide whitener. (This latter technique is generally accepted to be the unofficial standard for at-home teeth whitening systems.)
What does dental research show?
In regard to comparative effectiveness, Gerlach  (use this same link for the remainder of references mentioned on this page) found that teeth-whitening strips make a more effective choice than many other at-home approaches, such as whitening toothpaste or paint-on whiteners.
And although the research performed by Bizhang  did not find whitening strips to be as effective as (10% carbamide peroxide) tray whitening, many other studies (Ferrari , Gerlach , Hannig , Karpinia ) have.
Teeth whitening strips typically make a good (first) choice.
The above findings suggest that most people who use whitening strips should expect to see at least some level of results. And for a very large percentage of these people, this level may be quite satisfactory.
If you need better results, talk to your dentist.
Of course, there's no way to know precisely how effective any type of bleaching system will be for any one individual. There are simply too many variables involved (including type of tooth staining and user compliance with directions). There are also some inherent disadvantages associated with using whitening strips, although they are relatively minor.
All this being said, if after trying a whitening-strips approach you feel that you haven't achieved the success that you are seeking, you can re-discuss matters with your dentist. In light of your recent bleaching experiences, they may suggest that an at-home tray or in-office whitening approach might provide a more effective alternative.