How effective are teeth whitening strips?
Most of the research we've read ( clinical studies evaluating the effectiveness of teeth whitening strips ) suggest that strips coated with a 6% hydrogen peroxide whitener (like Crest Whitestrips ® Classic) can be expected to substantially approach those whitening results produced by a tray-based system employing a 10% carbamide peroxide whitener (a technique generally accepted to be the unofficial standard for at-home teeth whitening systems). [Crest Whitestrips is a registered trademark of the Proctor & Gamble Company.]
What type of results will you get when using whitening strips?
Of course, there is no way to know in advance precisely how effective any type of bleaching system, including teeth whitening strips, will be for any one individual. This is because there are simply too many variables involved (including type of tooth staining and the user's compliance with their product's directions.)
Teeth whitening strips typically make a good choice.
Despite the fact that there are some inherent disadvantages to using teeth whitening strips, the ease and relatively low cost associated with implementing a strips-based system typically makes this approach a good (at least introductory) bleaching choice.
What does research show about whitening strip effectiveness?
In regard to comparative effectiveness, Gerlach [2003] (use our 'clinical studies' link above) found that teeth whitening strips make a more effective choice than other at-home approaches such as whitening toothpaste or paint-on whiteners.
And although research performed by Bizhang [2009] did not find whitening strips to be as effective as a 10% carbamide peroxide tray-based system, many other studies have (Ferrari [2007], Gerlach [2000][2003], Karpinia [2002]). This suggests that most people who use whitening strips should expect to see at least some results. And for a very large percentage of these people, it may very well be a very satisfactory one.
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 whitening or in-office "laser" whitening approach might provide a more effective alternative.
What type of whitener is applied to teeth whitening strips?
Most teeth whitening strips are coated with a hydrogen peroxide-based whitener. For example, Whitestrips ® Classic (the first whitening strip product) are coated with a 6% hydrogen peroxide whitener. Strips can also be purchased that have a 9.5% (Whitestrips ® Renewal) or 10% hydrogen peroxide coating (Whitestrips ® Premium and Premium Plus).
A whitener's formulation will also include compounds that give it an adhesive nature. This stickiness factor helps to hold each strip in intimate contact with the surface of the teeth it is treating and helps to keep the strip from slipping around.
Since only one side of each strip is coated with whitener, the plastic strip serves as a barrier that helps to minimizes the contact of the hydrogen peroxide whitener with saliva and user's soft tissues. This helps to increase the effectiveness of the whitening process and minimize the whitener's potential for creating side effects.
Why do different whitening strip products come with different whitener concentrations?
Dental research has shown that the whitening effect produced by peroxide tooth whiteners is simply a function of concentration and treatment time. In the case of teeth whitening strips, the directions you find with each product evidence this.
While intended to deliver the same total dosing of hydrogen peroxide (and therefore the same level of whitening results), the directions for 10% hydrogen peroxide whitener strips (Whitestrips ® Premium) state they should be used over the course of 7 days whereas the 6% kits (Whitestrips ® Classic) come with enough strips for 14 days of treatments. The (roughly) 'half as strong' strips are used for twice as long.
What is the science associated with bleaching teeth with whitening strips?
The chemistry associated with hydrogen peroxide tooth bleaching (teeth whitening strips) is essentially the same as carbamide peroxide whitening (tray-based teeth whitening systems). In fact, when a carbamide peroxide whitener is used it breaks down into hydrogen peroxide, which in turn produces the tooth-bleaching effect.
In general, peroxide teeth whitening involves thin-film chemistry. This simply means that to achieve a bleaching effect one does not need to use a lot of peroxide but instead just enough to cover over the surface of the teeth being lightened. Teeth whitening strips, as a technique, simply take this concept to an extreme. The coating of whitener that is applied to strips is roughly .20 millimeters thick. (A piece of paper generally measures about .1 millimeters in thickness.)
Bleaching relapse and the need for touch-up teeth whitening treatments.
The stability of the whitening results created by teeth whitening strips can be expected to be essentially the same as those created by any other peroxide-based teeth whitening approaches (tray whitening, professional "laser" whitening, paint-on whiteners). For the simple reason that the underlying science associated with each of them is fundamentally the same.
One study (Gerlach [2004]) evaluating the results produced by teeth whitening strips found no significant color relapse after 6 months. These findings are on par with those results that have been reported for tray-based teeth whitening systems.
All teeth whitening approaches eventually require touch-up treatments.
Those whitening results produced by any bleaching method (including teeth whitening strips) will, at some eventual point in time, show some degree of fading and will require touch-up treatments so to restore its original luster.
Peroxide-based teeth whitening works by way of cleaving up (oxidizing) pigmented compounds that have become entrapped in a tooth's enamel layer into colorless byproducts. Any continued post-treatment exposure to chromogenic agents (coffee, tea, colas, red wine, tobacco products, etc...), has the potential (typically correlating to the level of exposure) to produce renewed tooth staining. The only way to remedy this newly formed stain is by way of performing additional whitening treatments (touch-up treatments).
Since touch-up whitening treatments typically involve creating a relatively lesser degree of lightening effect, they usually require less time and product than the person's original whitening efforts.
