Teeth whitening
White teeth have long been associated with beauty and good health. In addition people with whiter teeth are usually more confident and less self-conscious about smiling. Unsurprisingly therefore teeth whitening is nothing new.
The Egyptians were the first to use toothpaste which was then made from powdered pumice and vinegar while the Romans believed that urine would keep their teeth healthy and white.
In the 17th and 18th centuries barbers actually performed teeth whitening procedures (hence the white on the red and white barber's poll). However the process involved the painful filing down of the teeth followed by the application of highly-corrosive nitric acid. While this did whiten the teeth, it also destroyed the enamel ultimately causing the teeth to decay quicker.
The most common forms of the discolouration of teeth are aging, chemical damage to teeth and staining. Staining is principally caused by cigarettes, coffee, cola, tea and red wine, although certain medications can also cause significant discolouration.
Traditional treatments
We've come a long way from using nitric acid to whiten teeth, but until recently the most common method of whitening has involved the use of external bleaching solutions using oxidising agents. Basically there are two kinds of non-laser teeth whitening procedures: in-office and in-house bleaching.
In-office bleaching
In-office procedures are performed by a dentist and will involve the dentist documenting the pre-treatment shade of the patient's teeth. The dentist will then perform a traditional dental cleaning of the teeth in order to prepare the enamel for the bleaching treatment.
Since the bleaching agents used in professional teeth whitening systems are peroxide based they are caustic and can damage the gums and oral tissue. In order to protect these a dental dam is placed over the patient's teeth. The dam is a thin sheet of latex with holes punched in it so that it can be slipped over the teeth in order that they can be treated safely without any risk of the bleaching agent getting on the patient's lips or gums.
Alternatively instead of using a latex dam, a gel can be painted around the teeth which are then cured to provide a seal. A cheek retractor is then used to help ensure that the lips and gums are held back out of the way. While this treatment provides results that are immediately noticeable it may require the additional use of an at-home teeth whitening product to maintain the results.
At-home bleaching
There are a variety of 'at-home' procedures for teeth whitening. From toothpastes containing 'whitening' agents, to teeth whitening strips and 'paint-on' products. However the most effective of the home-based solutions is tray-based teeth bleaching.
This system uses a plastic tray which has been made to fit comfortably over a person's teeth into which a person places bleaching gel. The tray is then worn for several hours each day for a number of weeks until the whitening effect is achieved.
The disadvantage with this system is that it is extremely time consuming and there are no immediate effects. In addition although the process is safe the process is not directly supervised by a dental practitioner.
Generally both in-office and at-home bleaching techniques have been more effective in removing the stains caused by coffee, tea and tobacco rather than those caused by medications and fluoride. The main reason for this is that the tooth enamel proves relatively impermeable to bleaching agents limiting their effect to a superficial depth.
Laser treatment
Increasingly dental practitioners are recognising the effectiveness of dental laser systems in providing a more effective whitening solution to traditional methods. The treatment is very similar to in-office whitening in that laser treatment also requires the application of a hydrogen peroxide gel. The gel contains a dye that absorbs the light emitted by the laser in order to increase the reactivity of the bleaching composition.
The dental laser emits the laser energy required in order to excite the hydrogen peroxide molecules. This creates an oxidising effect, breaking down the gel into oxygen free radicals and water. The oxidising agent then reacts with the stain in the tooth reducing the discolouration and thereby creating the desired whitening.
The overall effect is an immediate whitening of the treated area which has been shown to last longer than traditional bleaching methods. Another advantage is that difficult to remove stains can be specifically targeted without having to e xpose the whole mouth.
Laser whitening is pain-free, quick and is not invasive.
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