Effects of Bleaching On Teeth

Bleaching is one of the most popular ways of whitening your teeth. Almost every one desires a whiter, more beautiful smile, especially those whose teeth are heavily stained and discolored or simply just yellow.

Bleaching involves the use of bleaching agents such as Hydrogen Peroxide and Carbamide Peroxide on the teeth. Hydrogen peroxide is used in concentrations of 3-16% while Carbamide peroxide concentrations range between 10-44%. The latter is usually preferred by dentists as it is considered more stable and less harmful to tooth substance.

These bleaching agents are added to gels, which are applied to the teeth. A tray that fits around the teeth contains this gel, and is placed over the teeth. A blue activating light such as a plasma arc, halogen or LED light is used to activate the bleaching agents. This is a way to provide heat energy to the bleaching agents, to cause movement of the molecules in the gel and in turn, cause teeth to whiten.

What happens during bleaching is that when the gel is activated by light, the bleaching agent is given enough energy to release free- radicals. A free radical is an unpaired electron, and is highly reactive and unstable. In order to stabilize, it must combine with another electron. So, the free radicals in turn react with other stable molecules to take an electron, thus producing more free- radicals and starting a vicious cycle of damage to the surrounding tissues. During bleaching, the free-radicals attack the pigment molecules in the teeth and break them down, hence making the teeth appear white. This does cause internal damage to natural tooth structure and demineralizes their enamel, but it isn’t significant enough to cause major harm to the teeth unless it is done too often.

When colored foods and drinks are ingested such as red wine, coffee and tea, the teeth can pick up on the color and return to their previous yellowish, stained form. Unless these foods are avoided, bleaching does not last long. Patients usually get teeth bleaching done once in a year or every two years, which isn’t too harmful as the teeth have an intrinsic ability to remineralize when given a an environment of high calcium and fluoride (such as while brushing teeth or drinking milk).

To summarize, teeth bleaching can be harmful when done too frequently, if the concentration of the bleaching agent is too high or if the bleaching agent is used improperly. Teeth bleaching is otherwise not harmful to the teeth and can be done once in a while to maintain that beautiful, white smile we all want.