Because the teeth are one of the most conspicuous parts of the human body, products that maximize their whiteness has always been a major component of bodily esthetics. Perhaps the catchiest song from the musical Annie is “You’re Never Fully Dressed Without a Smile,” an advertising ditty for Iodent toothpaste. The famous writer Aldous Huxley, in his 1958 book Brave New World Revisited, refers to a similar toothpaste jingle, “You’ll wonder where the yellow went when you brush your teeth with Pepsodent.” This article deals specifically with teeth whitening, which is also known as dental bleaching, and how it works its magic on the teeth.
What whitening is
Teeth whitening can be applied in different ways, some by the individual himself or herself, some by a dentist and still others at spas. Dentists generally bleach the teeth by painting the gums and the papilla with a light-cured substance to protect the softer, more tender tissues against burning by harmful chemicals. For this type of bleaching, hydrogen peroxide is used, either in its conventional pure liquid form or combined with urea in a solid known as carbamide peroxide. If the latter option is used, the mouth breaks down the solid into hydrogen peroxide.
Dentists may also use a procedure called light-accelerated bleaching, in which the bleaching process is sped up by means of energy from a light, usually plasma arc, halogen or LED. The second is generally considered by experts to be the most effective. The aim of light-accelerated bleaching is to excite the molecules of hydrogen peroxide; this effect is best achieved with energy from the blue end of the spectrum, which has the shortest wavelength and therefore the most energy. In recent times the waiting period has been shortened through the use of ultraviolet radiation and minimal heat.
Take-home whitening kits
Bleaching kits are now being made that patients can take home and use on their teeth. Such kits can be obtained at the dentist’s office. First, an impression is made of the patient’s teeth. This is taken to the lab, and is usually ready in three weeks or so. The dentist also records the color of the teeth at the time the impression was made. That way, any change in color due to the bleaching may be seen. Once the kit has been put together, the patient can use it for one hour per day during the first two weeks and for touch-up applications after that.
It is recommended by the American Dental Association that anyone who wishes to have his or her teeth whitened should first consult a dentist.