Questions & Answers

Read this before you whiten your teeth! This information about Teeth Whitening/Tooth Bleaching is to help consumers in the UK make an informed decision about whitening their teeth.

More and more people are choosing to whiten their teeth to make their smile more attractive. First impressions are important when meeting people and a whiter, healthier looking smile is always an advantage. Here are the answers to the most frequently asked questions we get from our patients.

Why do teeth darken?
Why go to a dentist for tooth whitening?
Who is legally entitled to do tooth whitening?
How does whitening work?
What is in the gels that the dentist uses?
How safe is tooth whitening?
Why don’t I buy whitening products from the chemist?
Why not buy whitening gel on the internet?
Are there different ways a dentist can whiten teeth?
How much does tooth whitening from the dentist cost?
Are there any side effects?
Are there contraindications to tooth whitening?
Are children or adolescences candidates for tooth whitening?
How long does tooth whitening last?

Why do teeth darken?

Some people have naturally darker teeth than others, but generally teeth darken with time. Dentists classify staining into extrinsic and intrinsic staining. Extrinsic stains are caused by red wine, tea, coffee, smoking and certain colourings in foods and can be polished off the teeth to some extent. This is usually done by an oral hygienist. Intrinsic staining is the internal colour of the teeth.  The internal colour of teeth slowly darkens with age but there are certain chemicals that can rapidly darken teeth for example antibiotics such as tetracycline and minocycline (often used to treat acne in adolescents) and excess fluoride whilst the teeth are developing can cause light and dark patches on the teeth.  Trauma to a tooth can also cause intrinsic darkening if the nerve is damaged. The most common causes however are bacterial plaque and tartar, caries (tooth decay) or stained white fillings.

Dental Shade Guide

Dental Shade Guide

 

Whitened Teeth

Whitened Teeth

 

 

 

 

 

Tooth whitening in the UK is considered by the General Dental Council to be the practice of dentistry. Any non dentists whitening teeth in sports clubs, shopping centres or beauty parlours are doing so illegally.  Dentistry can also only be practised from a location that is regulated and inspected by the Care Quality Commission. Sports clubs, shopping centres and beauty parlours do not fall into this category.

Why go to a dentist for tooth whitening?

Having a thorough examination by a dentist is important before whitening teeth because it is essential to know why a tooth or teeth have darkened. As described above, a tooth will darken if it has been damaged by trauma or infection and the nerve has died and formed an abscess. In this case the solution is not just whitening but treating the tooth with Root Canal Therapy prior to whitening. If the teeth have darkened because there is decay between them or leaking fillings, these problems need to be treated before whitening.

Only a dentist can make custom made bleaching trays which require impressions of your teeth using properly tested and licensed gels.

Bleaching gel and custom made trays

Bleaching gel and custom made trays

 

Who is legally entitled to do tooth whitening?

Legally it has to be a dentist or dental hygienist or dental therapist, on the prescription of a dentist.

How does whitening work?

Dentists use a peroxide based gel that has been tested and licensed for use in the practice of dentistry.  The gel soaks into the tooth structure by penetrating the enamel and dentin and oxidises the coloured pigments. This ‘bleaches’ the colour and results in whiter looking teeth without any abrasion or damage to the tooth structure.

What is in the gels that the dentist uses?

In the UK the regulation states that the dentist can use up to 6% hydrogen peroxide or the equivalent (18% Carbamide Peroxide which is a mixture of 6% hydrogen peroxide and 12% urea).

How safe is tooth whitening?

An American academic, Prof Van Haywood first described how he whitened teeth in 1989. We now have 20 years of data that dentist managed tooth whitening is completely safe. Prof Haywood and other researchers have done long term follow up studies on hundreds of cases and they have found that whitened teeth are completely normal and are not damaged in any way by the whitening process.

Why don’t I buy whitening products such as whitening toothpaste etc.  from the chemist?  It will be much cheaper after all.

The permitted level of hydrogen peroxide in over the counter products is only 0.1% hydrogen peroxide. That is 0.001666 (roughly 1/100) as strong as the products that a dentist can use. As a result they are not very effective.  To make up for the low concentration they sometimes contain abrasives that scour your enamel which can be damaging.

Why not buy whitening gel on the internet?

You simply do not know what you are buying.  Are they genuine or counterfeit gels? Do they contain hydrogen peroxide or carbamide peroxide? What strength? Can you trust the sell by date? A common gel sold is Chlorine Dioxide which is very acidic and etches tooth structure making them feel rough.  Teeth also lose their lustre and can be permanently sensitive.

Are there different ways a dentist can whiten teeth? I see so many different things advertised like “Laser bleaching in your lunch hour”.

There are broadly speaking three ways a dentist can whiten teeth.

1. Home whitening with custom made trays – The dentist makes custom made trays and then supplies you with the trays and gel (usually 10 to 18% carbamide peroxide). You then apply the gel to the tray and wear the tray at home. This should be worn for two to six hours and a typical course is 12 treatments.  The longer it is worn the better it works so sleeping with the trays in position is ideal. The treatments do not have to be on consecutive days, so skipping days is not a problem as the effect is cumulative. This way of whitening is considered to be the gold standard in tooth whitening as most of the research has been done with this method with great results. In fact 10% carbamide peroxide is the best as the stronger gels cause more transient sensitivity.

Custom made bleaching trays in position

Custom made bleaching trays in position

Whitening Kit at 92 Dental

Whitening Kit at 92 Dental

Whitening kit contents

Whitening kit contents

 

 

 

 

 

2. Home whitening without custom made trays – The dentist can supply you with a kit that allows you to put a tray over your teeth with gel (6% hydrogen peroxide) inside the tray. The trays are not custom made so you mould the trays to form around your teeth.  This can be worn for two to three hours and then discarded.  Several applications will be needed. This is the cheapest form of dentist tooth whitening but is not as effective as the first method.

3. Laser/Light activated surgery whitening – The dentist can do the whitening for you in the practice.  6% hydrogen peroxide is used and the gels are “activated” with a light or laser which also gives off a bit of heat. This method is however controversial.  If someone were to sit with their mouth open for 45 minutes without any treatment being done to their teeth, the teeth would whiten through dehydration. It can take up to 4 days for the teeth to rehydrate and return back to their original shade.  So if the dentist does one application of light/laser activated whitening then the immediate effect will be very good, partly due to dehydration. However if the colour or shade is checked one week later the change will be marginal as the teeth will have rehydrated.  To achieve a long term benefit at least three sessions will be needed or one session in conjunction with home whitening. This is usually more expensive than the other methods. 

Shopping mall tooth whitening.

Shopping mall tooth whitening.

 

How much does tooth whitening from the dentist cost?

Generally, dentists in different postcodes tend to have different fees, but the spectrum is typically between £150 and £800. Go to Contact Us.

Are there any side effects?

There is really only one and that is sensitivity.  This however is transient and is completely reversible.  Sensitivity can also be managed by stopping for a while or skipping days, or by treating the top teeth and the bottom teeth on alternate days. Desensitising toothpaste placed in the tray does help as well as certain desensitising gels containing potassium nitrate and fluoride or amorphous calcium phosphate.

Are there contraindications to tooth whitening?

There are no absolute contraindications however there are situations where whitening may not give the desired result. Very translucent teeth will become more translucent and can look darker after whitening. Porcelain crowns, bridges and white fillings will not whiten and may appear too dark and need replacing after whitening.  However in some cases crowns, bridges or veneers can be an indication in that with time the teeth around them darken and the crowns or veneers do not.  Then after whitening they will blend in as well as when they where first done.  Each case is different. These are all reasons to see the dentist before embarking on treatment to discuss all these possible problems and their solutions to get the best result.  

Are children or adolescences candidates for tooth whitening?

This is controversial. Currently, UK regulations prohibit whitening for under 18s, but exceptions can be made for treating and preventing disease at the discretion of a dentist. 

How long does tooth whitening last?

It differs from person to person according their lifestyle and also the initial shade.  However it is a good idea to do annual maintenance whitening for a day or two. This is easily done if you have the custom made trays which you can keep and reuse. Your dentist will happily supply you with the required amount of gel when needed.