Everyone would like to have a nice bright smile, so it comes as no surprise that the popularity whitening and bleaching procedures has increased dramatically in the recent years. However, the desire to whiten one’s teeth is not a new phenomenon. Records indicate that ancient Egyptians and Romans were among the first to uncover various methods to whiten teeth. For example, ancient Romans used urine and goat milk to whiten their teeth. This concoction is not as far-fetched as it might first appear. Urine, contains ammonia which is a cleaning agent found in many household products. But today there’s no need to rinse the mouth with urine, which incidentally is usually sterile. Chemistry has given us more effective products.
The American Dental Association (ADA) monitors the use of these various tooth-whitening products. Despite the diversity, there are two basic mechanisms of action to whiten teeth. The non-bleaching products, such as whitening toothpastes, contain chemical agents, which simply remove surface stains and debris in order to restore the tooth’s surface colour. By contrast, the peroxide-containing bleaching products work by actually changing the colour of the tooth.
The majority of bleaching products contain carbamide peroxide which breaks down into hydrogen peroxide and urea. The active bleaching agent is hydrogen peroxide, H2O2. This compound is a weak acid with strong oxidizing properties. Hydrogen peroxide attacks and destroys the coloured substances that cause stains. Oxidizing agents steal electrons and since electrons are the “glue” that hold atoms together in molecules, the molecules that cause stains to fall apart.
As with any intervention there is always the possibility of side effects. Tooth sensitivity has been reported to occur during the early stages of the bleaching treatment. During the later stages, tissue irritation may develop causing minor discomfort. Both of these side effects will subside once the bleaching treatment ceases. Unfortunately, there have been some cases in which irreversible tooth damage has occurred, usually through improper application. The time the bleaching agent is left on is critical and can best be judged by a dentist. Whitening strips are safe enough, but not very effective. And if you want really pearly whites, a dentist will be happy to discuss veneers and caps.