The short version is tooth whitening works and can be achieved with little to no damage to your teeth.
There are pros and cons for the different options; however, for several reasons, Home Whitening with Dentist Made Custom Trays is the best option.
Whichever method of whitening you decide, it is always a good idea to get your dentist’s advice before starting.
There are 2 general reasons for tooth discolouration
Intrinsic (internal) staining- include tooth developmental disorders, age, antibiotics, fluorosis.
Extrinsic (external) staining- include smoking, food and drinks
Please note a tooth can appear dark for other reasons, i.e. tooth decay, the infected tooth, plaque and calculus build-up all of which require treatment.
The Chemistry of Whitening
Stains on teeth consist of compounds called chromogens (staining agents). Whitening is the chemical degradation of chromogens. The active chemical is hydrogen peroxide, and it usually comes in 2 forms, one as hydrogen peroxide or the other as carbamide peroxide (which in contact with water breaks down to hydrogen peroxide).
The hydrogen peroxide oxidises the chromogens (i.e. breaks up the double bond of organic chromogens), and this chemical reaction causes the chromogen to appear lighter.
The Options of Whitening
In most whitening toothpaste is more abrasive than standard toothpaste and contains more detergents to remove extrinsic stains. Unfortunately, abrasive toothpaste can wear away the stain but also wear away the enamel, hence damaging the tooth structure. Also, in the long term, the tooth can appear darker by making the enamel thinner, which in turn makes the darker dentine (inner tooth surface) more apparent.
Over the Counter Strips, Gels, Rinses
Usually contains low concentrations of hydrogen peroxide. They do work; however, some over the counter products have been shown to cause damage to composite resin restorations (tooth coloured fillings). Please read the label as not all over the counter whitening products contain the appropriate ingredients.
Home Whitening with Dentist Made Custom Trays
Home Whitening with Dentist Made Custom Trays is the preferred method as this does not cause damage to tooth or fillings and is the most effective. A dentist takes impressions of the mouth and constructs custom trays. The hydrogen peroxide placed inside the trays and they are worn at home usually 30-60mins a day. Dentist Home Whitening with Dentist Made Custom Trays allows the hydrogen peroxide to have more contact time with tooth structure, and it also enables us to have a moderate concentration of hydrogen peroxide (3% to 9.5%). Unfortunately, teeth naturally discolour over time and usually, every 2 years or so, teeth need to be re-whitened (usually only for a short period). Another advantage is once trays are constructed and as long as things have not changed the trays can be reused. Usually this method is the most cost-effective long term.
In this process, the dentist cleans the teeth, apply a protective barrier on the gingiva (gums) and then apply hydrogen peroxide on the tooth at even higher concentrations (usually 15% to 35%). The advantage is this whitening process is it is quick, i.e. in a 1 to 2-hour appointment. In some practices, blue light or a laser may be applied to the whitening agent however it has been shown to be of no benefit. Also, high concentrations of hydrogen peroxide can cause enamel softening, surface roughness, an increase in the susceptibility of the tooth to dehydration and demineralisation (loss of minerals) and an increase in tooth sensitivity. Tooth sensitivity can be offset by using hydrogen peroxide with fluoride.
Things to Consider
These whitening methods may not be effective when
- Fillings are discoloured. The whitening agent does not change the colour of restoration, i.e. fillings or crowns. Also, as fillings and crowns do not change colour, fillings that are even well-matched that are visible may need to be replaced for best cosmetic results.
- Intrinsic discolourisation, i.e. discoloured tooth from previous root canal therapy, trauma, and infected tooth.
Also, whitening agents can cause tooth sensitivity. In most cases, teeth are sensitive following teeth whitening procedure; however, it usually diminishes with time.
If the whitening agent makes contact with your gum, you may experience gingival irritation. This side effect is temporary.
Whitening is not permanent; most people chose to reapply more bleaching every 2-3 years.
The Australia Regulations
‘From 1 May 2013, teeth whitening products containing concentrations of greater than 6% hydrogen peroxide and/or greater than 18% carbamide peroxide can only be dispensed by registered dental practitioners as part of their dental practice. It is expected that the practical outcome will be that after a patient consultation, a dentist can use both higher-strength teeth whitening products within their surgery and also dispense patients with take-home kits. It is important to note that the policy on teeth whitening developed by the Dental Board of Australia (DBA) under Section 39 of the Health Practitioner Regulation National Law Act (National Law), as in force in each state and territory, states that teeth whitening products should only be used by a registered dental practitioner with education, training, and competence in teeth whitening.’
(source Australian Dental Industry Association)