There has been a surge of interest in and demand for Tooth Whitening by the general public in Ireland over the last number of years. This interest has been driven to a large extent by images portrayed in the media of celebrities displaying bright white teeth and also by pharmaceutical companies anxious to sell new products. This is despite the fact that adult teeth are not normally bright white but more of a creamy white yellow appearance. As we age our teeth become darker in appearance. This can be due to staining but mostly it is a natural phenomenon.

So, how does tooth whitening work?

In the late 1960’s it was discovered that 10% carbamide peroxide, which is equivalent to 3% hydrogen peroxide, was capable of whitening teeth. This product has been studied carefully since 1989 and has been licensed for use in the U.S. by the Food and Drugs Administration (FDA).

Hydrogen peroxide, or its derivative carbamide peroxide, is held in contact with the outside surfaces of teeth. The ‘whitening’ or lightening effect occurs following prolonged penetration of hydrogen peroxide throughout the entire substance of the tooth and the subsequent release of oxygen.

Is tooth whitening right for you?

To determine if tooth whitening is right for you, start by talking to your dentist, who will need to accurately assess the underlying reasons for discoloration of your teeth and advise if you are a good candidate for bleaching.

In some cases, it may be more appropriate to pursue other treatments, especially if you already have crowns or bridges, as their colour will not lighten like natural teeth when bleached. White fillings may need to be repaired or replaced after whitening for the same reasons.

If tooth whitening is recommended, your teeth and gums should be healthy and free of dental decay before you commence treatment.

Tooth whitening options in Ireland

In September 2011 the Council of the European Union amended the European Cosmetics Directive regarding the use of hydrogen peroxide in tooth whitening products. The revised directive provides that tooth whitening products containing hydrogen peroxide greater than 0.1% and less than 6% only be sold to dentists and used appropriately by them on consumers over 18 years of age. The dentist may also supply these products for home use to continue a course of treatment.

The options that are available through your dentist in Ireland include:

Dentist-supervised home bleaching

In this instance, your dentist will advise the correct choice of bleaching kit and construct a clear plastic mouth tray for the bleaching gel, which is a custom fit for your mouth. The snug fit of this tray will maximise contact between the bleach and tooth surface and minimise contact of the bleach with the gums.

Bleaching kits containing 10% carbamide peroxide (equivalent to  3% hydrogen peroxide) are ideal and have a long-term safety record. The gel is syringed into the specially constructed trays and worn at nighttime for two to six weeks. The majority of cases look good after two weeks.

Dentist applied in-surgery bleaching systems

Here, dentists use the same basic materials but apply hydrogen peroxide in stronger concentrations, which is now limited to 16% carbamide peroxide (equivalent to 6% hydrogen peroxide).

Despite claims to the contrary, there is no evidence to show that in-surgery bleaching with or without a high intensity light produces a better result than dentist supervised home bleaching, which is also considerably less expensive. Several studies have shown that there is no difference after two weeks between different bleaching techniques, including dentist supervised home bleaching.

There are greater risks attached to using high strength hydrogen peroxoide whitening treatments and great care has to be taken to avoid injury to soft tissues. There is also greater risk of sensitivity to the teeth both during and after bleaching.

Does dental bleaching cause side effects and can they be prevented or alleviated?

The most common side effect of bleaching is tooth sensitivity. This can be prevented before bleaching by using special toothpaste for tooth sensitivity for two to three weeks beforehand. If the teeth are very sensitive either during or after bleaching the dentist may recommend applying special desensitising toothpaste to the teeth on a tray for between 10 to 30 minutes. In some circumstances bleaching may be stopped altogether or carried out on alternate days.

Some patients complain of gum irritation and a chemical taste in the mouth. A better fitting appliance, made by a dental laboratory, will reduce this risk as its custom fit prevents peroxide leaking on to the gums.

It is also recommended that teeth whitening products should not be used in pregnancy and should be used with caution by people who continue to smoke and drink alcohol.