The truth about teeth whitening

Teeth whitening is the process of bleaching teeth to make them whiter. According to a Cosmetic Surgery Solicitors’ survey, it’s the most common cosmetic dentistry caried out in the UK, ‘with nearly a quarter (24%) [of people surveyed] whitening their teeth either with a home kit, through a dentist surgery, or at a specialist clinic.’ In the digital age of social media influencers promoting home teeth-whitening kits that promise pearly whites, it's almost impossible to escape these seemingly miracle products. In our latest article, leading London-based orthodontist, Dr Chaw-Su Kyi explains exactly how the procedure works and the advantages professional teeth whitening has over DIY treatments.  

How does teeth whitening work? 

Firstly, your dentist will carry out an assessment of your teeth to make sure the teeth and gums are healthy enough to have tooth whitening procedure.  

The dentist will be able to manage your expectations of the procedure following the assessment. For example, often yellower shades of teeth will whiten better. Teeth that are discoloured due to internal trauma may need to be whitened internally. Whitening products will not work on crowns or veneers. Stains on teeth caused by smoking or medication will take longer to remove. 

A number of factors should be discussed by your dentist to help you choose the correct whitening product. In whitening gels there is always one of the following active ingredients,  hydrogen peroxide or carbamide peroxide. Hydrogen peroxide 'breaks down' faster than carbamide peroxide to release the whitening, so it has a shorter life, meaning shorter wear times for the patient. Carbamide peroxide contains hydrogen peroxide, which is released slower, over a longer period of time. It’s used, for example, in whitening trays that are worn overnight, and is often a gentler way of whitening. Both active ingredients have been shown to produce equally effective results, the right type of whitening product depends on the type of staining your teeth have, along with taking into account the factors above.   

Is it safe? 

When carried out professionally, teeth whitening is safe. With whitening products from a dentist, for example Phillips Zoom Whitening, you also have Relief ACP gel which contains potassium nitrate and fluoride to help treat sensitivity from the whitening process. DIY whitening kits, on the other hand, generally only provide the ‘whitening’. You will get custom-made trays made by your dentist to ensure there is a snug fit and the whitening gel is working in the correct area. Increased sensitivity occurs when the whitening gel spreads to the gums and this can happen with poorly fitting trays (non-custom-made trays). 

What advantages does professional teeth whitening have over an at-home teeth whitening product? 

Staining on teeth can be either extrinsic (surface) or intrinsic. Alternative at-home-treatments will probably help remove the extrinsic surface staining but not change the actual colour of your teeth, the intrinsic staining. Hydrogen peroxide or carbamide peroxide can infiltrate the enamel, with the oxygen molecules from the whitening gel breaking down the discoloured molecules in your teeth, giving you the whiter smile. It is unlikely baking soda or charcoal will have this ability to penetrate the enamel. Whitening strips are unlikely to cover the whole surface of your teeth or the back teeth, and may leave you with uneven areas which have not whitened. If you do buy over the counter products, make sure you are buying from a reputable UK retailer, and not imported goods as it may contain high levels of hydrogen peroxide which can risk sensitivity to the teeth and gums if not administered correctly.  

It's always best to consult your dentist and have their professional advice. You must always remember that you only have one set of adult teeth to last a lifetime. Why risk damaging them by using unknown products? 

What type of results can patients hope for? How long does the whitening last? 

The results of teeth whitening vary from person to person. For some people, the results can last as long as 2 to 3 years, while for others it may be much shorter, lasting 6 months. Factors that will reverse the whitening process include:  

• Smoking 
• Driving tea, coffee or red wine 
• Eating beetroot/ turmeric type food 

As whitening only works on natural teeth and won’t affect the colour of any existing fillings, crowns, veneers, or bridges. These may need to be changed to ensure that the shades match the natural teeth.   

What advice can you give to help keep teeth white? 

Always start with the simple things: 

• Good oral hygiene to prevent plaque hardening and trapping food and drink stains. 
• Reduce consumption of staining types of foods and drinks. 
• Maintaining regular hygiene appointments with your dentist. 

Dr Chaw-Su Kyi is a leading orthodontist in London. To arrange an appointment with her, you can do so through her Top Doctors profile.