Typically, the performance of these tooth whitening products is measured in terms of their effectiveness, comfort, ease of use, and the number of shades of color change.  The best teeth whitening products use carbamide peroxide and the effectiveness depends largely on the percentage of peroxide in the product combined with the amount of time the teeth whitening product is in contact with your teeth.

Teeth whitening product reviews show that of the five categories of tooth whitening products on the market, the least effective by far are the whitening toothpastes and whitening sprays.  Typically with this kind of teeth whitening product there is very little in the way of noticeable change to the color of the teeth.  Not surprisingly, most dentists consider these kinds of teeth whitening products to be ineffective as well.

Brush on gels are slightly more effective than toothpastes and sprays.  They have been found to be able to whiten teeth by about one shade of color.

Whitening strips fare somewhat better on the scale of best teeth whitening products, but are not without problems.  While they are slightly more effective than toothpastes, sprays and gels, and for a longer period of use, the whitening of the teeth is not uniform nor is the entire visible tooth actually bleached.

Far and away the best teeth whitening products are the tray bleaching systems.  The three best teeth whitener tray systems are:  1) the non-moldable; 2) the boil and bite; and 3) the professional.  Of the three, the professional tray bleaching system is the absolute best teeth whitening product, followed by the boil and bite, and then the non-moldable tray system.

The non-moldable tray bleaching system, while comfortable and easy to use, usually contains less peroxide than the other tray systems and typically can only yield three shades of color change.  Additionally the tooth whitening is often uneven, and is therefore not the best teeth whitener option.

The boil and bite tray bleaching systems employ custom made mouthpieces and a higher concentration of peroxide than the non-moldable systems.  Accordingly, they are found to achieve as much as 9 shades of color change.

Again, the professional tray bleaching systems are the top teeth whitening products.  The mouthpiece is custom fitted and is usually made from actual impressions of your teeth taken at home and then sent to a dental facility where the mouthpiece can be constructed.  A tooth whitening gel is then applied to the mouthpiece which is then placed on the teeth.  These teeth whitener systems are able to achieve a remarkable 11 shades of color change.