What is tooth whitening?
Tooth whitening is a process used to chemically alter the colour of teeth. This is achieved by removing stains and discolouration by adding a whitening agent (hydrogen peroxide) to the tooth surface. This results in the tooth looking whiter and gives an overall more youthful appearance.
Why do teeth become discoloured?
The dazzling movie star teeth that you might see on TV are not a natural colour. Just because your teeth aren't as white as those Hollywood smiles, do not assume that your teeth are actually discoloured. There is a natural variation in the colour of teeth from person to person.
Age and lifestyle factors are the main reasons for tooth discolouration. As you get older, the teeth become darker due to natural erosion and exposure of the inner surface of the teeth (dentine), which is darker. The gums also recede with age, showing more root surface, which again tends to be a darker colour. The foods and drinks we consume also play a part. Drinks like red wine, tea and coffee can cause staining. Tar and nicotine from cigarette smoke are also major contributors.
How white will my teeth become with chemical whitening?
The answer to this question is dependant on several factors. To start off with, as mentioned earlier, our age, lifestyle and our natural tooth colour varies from individual to individual. For this reason, the effects of tooth whitening will vary. Most people, however, will respond very well to whitening treatments depending on what method is used. There are a small group of individuals who may only notice a small difference. The best person to advise you on your likely result will be your dentist. They will note your tooth colour before starting treatment, and they will try to estimate an outcome.
How does whitening work?
Tooth colour may be lightened using hydrogen peroxide (bleach). This may be done via external whitening or internal whitening.
There are two methods of external tooth whitening.
The dentist will prescribe a safe dose of whitening jelly to be used within close fitting gum shield trays. This is a lower dose than the one you would be given if you opted for chair side whitening. The trays will prevent contact with gums in order to prevent burns. You will have to wear the trays for about one hour each night , until you achieve the desired effect. This will allow the agent the time it needs to take action. These home whitening kits help you maintain a longer lasting result compared to the initial treatment alone. You can also top the colour up every month if required.
With this method of tooth whitening, the dentist will use a much stronger whitening jelly then the one used at home. The dentist can whiten both the upper and lower dental arch at the same time. The process is much shorter then home whitening, leaving you with a brighter colour and healthier looking result. The gum margin is protected by the dentist by painting on a protective layer, which is activated by a blue light. Once the process is finished the gel can be washed off. To maintain the colour, a home kit will need to be used. A combination of both products will result in immediate and long-term colour stability.
For those who have heavy staining and calculus, a pre-treatment scale and polish from the dental hygienist may be necessary to aid the whitening process.
Internal Whitening:
This is a more specialised method, reserved mainly for patients who have discolouration due to nerve root damage. Peroxide is placed within the tooth through a small syringe and a temporary dressing is applied over the tooth. This method usually takes longer than external whitening, with results being achieved within a few days. In some cases it may even take several weeks. The result is assessed by the dentist at regular intervals, and the process will be repeated if necessary.
Is tooth whitening safe?
Tooth whitening is very safe when used under careful instructions from the dentist.
The agent used comes in a gel form, which should not come into contact with the gums, as this may cause discoloration or burns. Most people experience no adverse reactions, but some patients may develop some sensitivity around the time of treatment depending on the strength of agent and method used. This can be easily resolved by using some sensitive toothpaste to mask the effect and by avoiding hot or cold food for 48 hours.
What are the benefits of tooth whitening?
Whitening is now relatively cheap and easily accessible from your dentist. The main benefit is a healthier looking smile without removing any of the tooth structure. Whitening is a much more conservative approach to changing a smile compared to crowns and veneers, as these methods result in changing the shape of the tooth.
Author: Dr Ahmed Farooq, BMedSci, BDS,MJDF (RCS Eng) Editor: Dr Shazan Chughtai, MB BS
