Whitening teeth is dependent on 3 factors:
• gel concentration
• frequency of application
• duration of exposure
Some products are lower concentrations to limit sensitivity, but are not as effective. Over time they will work enough to satisfy most people, so lower concentration products depend on higher frequency of exposure.
One visit methods have a lower frequency of application (once) so depend on higher concentrations of gel. This leads to sensitivity in some people, but also does not penetrate into the teeth as deeply as other methods.
Methods that allow long applications (such as night time tray application) increase total exposure, therefore deeper penetration. This leads to longer lasting results.
My experience is that the best bleaching method is not a product but a technique that uses many products. It is not as convenient as a single visit product, such as Zoom® or BriteSmile®, but lasts much longer and works better. Often called “Deep Bleaching” or “Extreme Whitening”, teeth get their whitest with this method.
