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National Public Health Service for Wales NPHS Briefing Papers: Dental Public Health
Tooth Whitening
TOOTH WHITENING
(amended January 2007)
1. What is tooth whitening?
Whitening is any process that will lighten the existing natural colour of your teeth
without removing any of the tooth surface. This can be achieved in two ways;
1. A product can bleach a tooth, which means that it actually changes the
natural tooth colour. Bleaching products contain peroxides that help
remove deep (intrinsic) and surface (extrinsic) stains.
2. Non – bleaching whitening products can be used which contain agents
that work by chemical or physical action to help remove surface stains
only.
2. How long has tooth whitening been used?
Tooth whitening has been practised by dentists for over 100 years. The history of
“modern day” tooth bleaching, however, began in 1989 and is credited to
Haywood and Heymann who introduced the nightguard method of vital tooth
bleaching. At the same time, Omnii International (USA), working with a dentist
named John Munro, developed and marketed the first commercially available
home-bleaching product to be used under dentist supervision.
Interestingly enough, this system was initially discovered quite by accident by an
orthodontist named William Klusmier. He instructed a patient to use an oral
antiseptic containing 10% carbamide peroxide in an orthodontic positioner, which
the patient wore at night, in an effort to facilitate tissue healing. The patient
returned with improved tissue health and, after using the product for an extended
period of time, his teeth were significantly lighter in colour. He began using this
technique to lighten teeth. From 1970 to 1975, Klusmier presented his findings at
several dental meetings. Haywood and Haymann attended one of these
meetings and initiated their clinical and laboratory investigations on the technique
as a result.
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Tooth Whitening
3. Why might I want my teeth whitened?
As with hair and skin colour, the colour of our teeth is genetically determined and
therefore varies between individuals. Our teeth tend to naturally darken as we get
older.
Teeth can be stained on the surface by food and drinks such as tea, coffee and
red wine. Tobacco smoking can also stain teeth. Acidic drinks and foods such as
fizzy drinks, fruit juice and yoghurt can cause the teeth to appear more yellow as
they cause erosion of the outer enamel layer allowing the underlying yellow
dentine to shine through.
Discolouration can also be caused by illness or the use of tetracycline antibiotics
while the teeth are forming. Minocycline, a tetracycline antibiotic, can cause
staining in adult teeth.
Deposits of calculus (tartar) that form around the necks of teeth can pick up
unsightly stains.
4. Who should decide if my teeth are suitable for whitening?
A thorough oral examination, performed by a dentist, is essential to determine
whether you are a candidate for tooth whitening and what type of whitening
system would provide the best results. If tooth bleaching is the treatment of
choice the dentist will then administer or supervise the use of bleaching agents
within the context of a comprehensive, appropriate treatment plan.
Only a trained clinician can diagnose the type of stain present. In some cases, it
may be sufficient to whiten teeth by removing surface stains with a thorough
prophylaxis which involves polishing teeth with pumice.
5. What are the different options for tooth whitening?
Whitening products may be administered or dispensed by dentists or purchased
over the counter. Professional bleaching is the most common and effective form
of tooth whitening. There are two techniques available for professional bleaching;
1. Dentist monitored home bleaching techniques.
2. In surgery bleaching techniques.
6. What do the different options for tooth whitening involve?
1. Home Technique
With this technique you bleach your teeth at home, under the supervision
of your dentist, using a tooth bleaching gel, usually 10% -20% carbamide
peroxide, which is held next to the teeth in a mouthguard.
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Tooth Whitening
Impressions of your teeth are taken by the dentist and a custom made
bleaching tray is constructed. The tray is lightweight, clear and fits closely
around the teeth to ensure that the bleaching gel can be applied to the
teeth without touching the gums. The dentist will show you how to put a
small amount of the bleaching gel into the tray and will demonstrate how
to slide it over your teeth.
You will then continue the treatment at home. The tray is worn for several
hours, usually at night time or when it is most convenient. A course of
treatment usually takes two weeks but may vary dependant on the
concentration of bleaching agent used. In cases of heavily stained teeth
the duration of treatment may be as much as six months.
Disposable trays pre-filled with 9% hydrogen peroxide gel which can be
adapted to fit around the teeth without the need for impressions have also
become recently available.
2. In Surgery Technique
This technique involves using either light-activated units for „power
bleaching‟ or lasers while you sit in the dental chair.
The dentist will apply a rubber dam or a gel to protect the soft tissues, and
a bleaching agent, usually containing 15-35% hydrogen peroxide, is then
applied onto your teeth. A light or laser is then shone on the teeth to
activate the chemical so that it acts more quickly on the discolouring
molecules within the tooth. The actual tooth whitening procedure will take
about one hour.
Before these tooth bleaching techniques are carried out the dentist will make
a note of your baseline tooth shade using a guide so that it can be compared with
the shade after bleaching on your follow up appointment.
The success of these techniques is determined by the initial colour of the teeth.
Generally, bleaching easily removes yellow with dark brown and grey stains
being more resistant to the process. As younger teeth are more porous it has
been suggested that they would be easier to bleach than older ones. With the
home bleaching technique it is important to remember that patient compliance
with the dentists instructions plays a crucial role in the success of the treatment.
7. What are the active ingredients in professional bleaching gels and how
do they work?
Bleaching gels contain either hydrogen peroxide or one of its precursors, notably
carbamide peroxide. Carbamide peroxide breaks down into hydrogen peroxide
and urea, with hydrogen peroxide being the active ingredient.
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Tooth Whitening
The success of any bleaching treatment is based on the ability of the bleaching
agent to permeate tooth structure to the source of the discolouration. Hydrogen
peroxide has a low molecular weight and therefore passes easily through enamel
and dentine. Bleaching is an oxidation of the discolouring molecules within the
tooth. Peroxides release free radicals which interact chemically with large organic
pigment molecules contained in enamel and dentine. These molecules are
reduced into smaller, less pigmented molecules.
8. How long does tooth whitening last?
Some individuals experience better effects from tooth whitening than others.
Tooth whitening should last for approximately 18 months to 3 years. At this point
you may chose to have a touch up treatment and the colour will usually change
to the optimal shade readily. The effect is less likely to last as long if you smoke,
or eat or drink products that can stain teeth.
9. Is tooth whitening safe?
The evidence on safety published to date tends to suggest that bleaching is a
relatively safe procedure.
Hydrogen peroxide breaks down into water and oxygen. Urea breaks down into
carbon dioxide and ammonia. Normal body processes easily handle all four
products.
It has been suggested that peroxides are mutagenic and can boost the effects of
known carcinogens. The American Dental Association (ADA), however, has
found no evidence that when used as directed, tooth whiteners increase cancer
risk or cause other problems. The ADA have acknowledged that bleaching
products are abused by some members of the public.
10. What are the side effects?
The most commonly observed side effects to hydrogen or carbamide peroxide
are tooth sensitivity to cold and occasional irritation of the soft tissues in the
mouth, particularly the gums.
Tooth sensitivity often occurs in the early stages of bleaching treatment. In most
cases, gum irritation is caused by an ill fitting bleaching tray rather than the
actual bleaching agent. Both of these conditions are usually temporary and
disappear within a few days of the treatment finishing. The use of desensitising
agents containing fluoride or different bleaching gel formulations can address the
sensitivity problem.
If you encounter any of these side effects you should consult your dentist.
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Tooth Whitening
11. Will tooth whitening damage my teeth?
Over bleaching can cause teeth to become chalky and translucent.
Several studies have been carried out to investigate the reaction of the pulp,
which contains the nerve and blood supply to the tooth, to the bleaching process.
Evidence shows that bleaching may either have no effect or may cause an initial,
mild, localised pulp reaction which is reversible several weeks post treatment.
There are no reports in the literature indicating that bleaching may exert a
negative impact on existing restorations. Defective restorations should, however,
be replaced before bleaching to minimise potential sensitivity.
12. How much does tooth whitening cost?
Whitening treatments are not available from your dentist on the NHS. Private
charges will vary between practices and between regions. In surgery bleaching
techniques tend to be more expensive than dentist supervised home techniques.
Patients are advised to contact their dentist to determine costs.
Existing crowns and fillings on the front teeth may also need to be changed
following the bleaching procedure which increase the overall cost.
13. How can I look after my teeth during and after whitening?
Personal habits may need to be modified to achieve and maintain the desired
goal of whiter teeth.
Teeth should be dry and cleaned of debris before any bleaching agent is applied.
During bleaching teeth may be slightly dehydrated and consumption of food and
drinks which can cause staining should be kept to a minimum. These foodstuffs
should also be kept to a minimum after tooth whitening. Stopping smoking will
also prevent staining of teeth.
14. What about whitening products bought ‘over the counter’?
Although cheaper, over the counter bleaching kits often contain an insufficient
concentration of hydrogen peroxide to be effective. Some may contain acetic or
citric acid as active ingredients. These acids have too low a pH (too acidic) and
can cause significant structural damage to enamel when used for extended
periods of time and worsen the discolouration through erosion. Bleaching trays
provided are not made to fit your mouth and can therefore cause increased
leakage and soft tissue irritation.
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Tooth Whitening
Whitening toothpastes do not affect the natural colour of teeth but may be
effective at removing surface (extrinsic) staining because they contain abrasives.
Before you use a tooth whitening product you should consult your dentist.
15. Are there any people for whom tooth whitening is not a good idea?
Individuals with a history of extreme sensitivity to hot and cold food or drink,
fracture lines in their teeth, large dental pulps, and severe loss of enamel may
not be suitable candidates for tooth whitening as the procedure may precipitate
sensitivity.
Decay, periapical lesions, and gum disease should be treated before any tooth
whitening procedure is carried out. Tooth whitening should not be carried out on
individuals with a peroxide allergy.
16. When might tooth whitening not work?
Tooth whitening only works on natural teeth and will therefore have no effect on
fillings, crowns, and veneers. If you have white fillings in your front teeth, these
should be replaced approximately 2 weeks post - bleaching to ensure a good
colour match and bond strength.
Very severe tetracycline stained teeth may not respond or have a limited
response to tooth whitening. In these cases, porcelain veneers may be the
treatment of choice. Mild to moderate tetracycline staining does, however, tend to
respond to extended bleaching regimes of 3-6 months. White fluorosis spots do
not tend to bleach but will become less obvious as a result of lightening of the
surrounding tooth area.
17. Can a single tooth which has been root filled be whitened?
Sometimes teeth become discoloured by the breakdown of tissue inside the root
canal when the nerve dies. It is hypothesised that the blood in the pulp chamber
undergoes haemolysis, which releases haemoglobin. The iron in the
haemoglobin then combines with hydrogen sulphide, produced by bacteria to
form iron sulphide, which is a very dark pigment.
Provided a satisfactory root filling, hydrogen peroxide or sodium perborate can
be placed inside the tooth (internal bleaching) under a temporary dressing. After
a week, the bleach is removed and a permanent filling placed to reseal the tooth.
Internal bleaching can also be combined with external bleaching.
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Tooth Whitening
18. Can I whiten my teeth while I am pregnant?
The effect of the bleaching gel on the foetus is unknown. You will swallow some
of the gel while you are bleaching with home kits. It is now generally accepted to
avoid unnecessary medical interventions during pregnancy in order to minimise
any possible risks to the health of the foetus.
19. Is tooth whitening legal in Britain?
A review of the legislation currently in force states that the supply of tooth
whitening products containing more than 0.1% hydrogen peroxide present or
released is an illegal act rendering the supplier vulnerable to prosecution. A
House of Lords judgement in June 2001 confirmed that tooth whitening agents
were covered by the EU Cosmetics Directive, and not by the Medical Devices
Directive. Practioners considering the supply and use of such materials thus
need to be acutely aware of this issue.
The defence organisation, Dental Protection, advises that notwithstanding the
current legal situation which suggests that the supply of these products is illegal,
dentists should take into account what is in the best interests of their patients.
When a decision is made to use any bleaching technique, it should be fully
discussed with the patient. The patient should be aware of the risks and benefits,
balancing the question mark over the legality of supply of these products with the
risks to the patient of the removal of healthy tooth structure if alternative
treatments are used. Comprehensive clinical records should be taken of the
consent process.
The British Dental Association states that there is nothing illegal or unsafe about
the technique of tooth whitening, as confirmed by the Chief Dental Officer in
March 2000. It is simply that the supply of the products has by accident become
caught by the EU Directive.
December 2006
The Department of Health has produced new guidance on this subject and
it can be found at http://www.dh.gov.uk/assetRoot/04/14/15/66/04141566.pdf
(Gateway 7510)
Key References
Attin T, Effect of Bleaching on Restorative Materials and Restorations – A
Systematic Review, Dental Materials 2004;20(9):852-861
Fugaro JO, Nordahl I, Fugaro OJ, Matis BA, Mjor IA, Pulp Reaction to
Vital Bleaching, Operative Dentistry 2004;29(4):363-368
Morris C, Tooth Whiteners – the legal position, British Dental Journal, April
2003;194(7):375-376
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Tooth Whitening
Sulieman M, An Overview of Bleaching Techniques: 1. History, Chemistry,
Safety and Legal Aspects, Dental Update 2004;31:608-616
Further information is available from the following website links:
The House of Lords Homepage. Judgements – Optident Limited and
Another v Secretary of State For Trade and Industry and Another.
www.publications.parliament.uk
Dental Protection Homepage. Tooth Whitening UK Position Statement.
www.dentalprotection.org
American Dental Association Homepage. Tooth Whitening Position
Statement.
www.ada.org
British Dental Association Homepage.
www.bda-dentistry.org.uk
The content of this Frequently Asked Questions Paper has been peer reviewed
by dental public health practioners in Wales to provide an independent and
evidence based response.
Claire Evans SHO in Dental Public Health
December 2004
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