Teeth Whitening Information

Teeth whitening is an effective way of lightening the natural colour of your teeth without removing any of the tooth surface or damaging it. Usually the original shade of the tooth is whitened to a lighter colour. It is not that the teeth are being turned completely white.

As we get older our teeth get darker. This is caused by the change in colour of the dentine inside our teeth as we age. Additionally, the enamel we are continually brushing becomes more translucent, thereby showing more of this ‘darkened’ dentine. The foods we eat and drink discolour teeth as do other habits, such as smoking. Tea, coffee, blackcurrant juice, red wine and other foods that have strong colours can have an effect on the overall colour of our teeth. Teeth may also darken as a result of some antibiotic therapy.

Some people naturally have a more grey shade of teeth. Other people have white spots on their teeth. This can be caused by early tooth decay, or illness when the tooth was forming. All of these appearances can be improved through teeth whitening.

There are a number of reasons why you might get your teeth whitened. Everyone is different; and just as our hair and skin colour vary, so do our teeth. Very few people have brilliant-white teeth.

Tartar can also affect the colour of your teeth. Some people may have staining under the enamel surface or tiny cracks can appear in the teeth which take up stains.

Here at The Guild Practice we will assess you first to see whether tooth whitening is suitable for you. We will tell you about the options you have for tooth whitening and which will be the most suitable for you.

The most popular type of teeth whitening is called ‘dentist-supervised home whitening’. You will have trays made specially to fit into your mouth like very thin gum-shields. The whitening gel is then put in the trays and you will be given a routine to follow at home.

The ‘active ingredient’ in the whitening product is usually hydrogen peroxide or carbamide peroxide. As the active ingredient is broken down, oxygen gets into the enamel and dentine of the teeth and the tooth colour is made lighter.

The total length of the home bleaching treatment can vary depending on how discoloured your teeth are and the shade you want to attain. It can usually be finished within two weeks. First, you will need up to four visits to the dentist. Your dentist will need to make a thin mouth-guard and will take impressions to do this at the first appointment. At your second appointment we will apply the gel to the trays, seat them in position and usually you will remain with us for about an hour for this first stage of teeth whitening. We will then instruct you in the application of gel in order that you can repeat the process at home with a less concentrated version of the peroxide gel. You will then need to continue the treatment at home. This means regularly applying the whitening product over two weeks, for approximately two hours at a time. We will discuss with you exactly how long you should keep your trays in your mouth. It is important to follow the instructions that you are given to get the best result.

There are some products which can be applied for up to eight hours at a time. This means you can get a satisfactory result in as little as two weeks.

If teeth have been root treated they can become very badly darkened. These teeth can be treated internally, once the root canal filling has been correctly sealed. This treatment involves placing an oxidising agent within the body of the tooth and sealing it within the tooth for week to two weeks. This can work very effectively and often in a very short space of time.

Chair-side whitening will be more expensive than professionally supervised home teeth whitening. For this reason we do not offer chairside whitening as the effects are no better and the extra cost brings no real benefit to our patients. For a course of full mouth teeth whitening using Optident White there is a charge of £450.

The effects of whitening can effectively last up to three years. However, this will vary from person to person. The effect is less likely to last as long if you smoke, or eat or drink products that can stain your teeth. We will give you an opinion before you start the treatment.

Some people may find that their teeth become sensitive to cold during the treatment. Others may have discomfort in the gums, a sore throat or white patches on the gum line. These symptoms are usually temporary and should disappear within a few days of the treatment finishing.

If any of these side effects continue you should contact us and advise us of any difficulties you may be having.

Here at The Guild Practice in Belfast we DO NOT RECOMMEND THESE. Home kits are cheaper but they are not always assessed for safety and tend to be more acidic. There is a chance that these products could damage your teeth and gums. Because teeth whitening is a complicated procedure we advise that you always speak to us before starting the treatment. Regulations covering home kits vary from country to country. Kits sold in Europe cannot legally contain more than 0.1% peroxide and this is too little to be effective.

In Europe and in some other countries outside of Europe teeth whitening can only legally be carried out by a dentist. So, teeth whitening by beauticians and in whitening kiosks is illegal. In Europe, it is illegal to supply bleaching material containing more than 0.1% peroxide (or the equivalent in carbamide peroxide) to anyone other than a dentist, or direct to the public.

These regulations are to protect the public. They make sure that anyone carrying out whitening is properly trained and has the right skills and knowledge to carry out the procedure without risking permanent damage to the teeth or gums.

Here at The Guild Practice we have had to root treat patients teeth that were killed after being whitened by one of these beauty kiosk.

There are several whitening toothpastes on the market. Although they do not affect the natural colour of your teeth they may be effective at removing staining, helping to restore the natural colour of your teeth. Therefore, they may improve the overall appearance of your teeth. Whitening toothpaste may also help the effect to last after your teeth have been professionally whitened.

We recommend that you look for our approved logo on the packaging of oral-care products. This is a guarantee that the claims made about the product have been scientifically and clinically checked by an independent panel of experts.

Sometimes. Many dead teeth become discoloured after a root filling. If the tooth has been root-treated, the tooth may be reopened. The whitening product is applied from the inside to whiten the tooth.

Tooth whitening can only lighten your existing tooth colour. Also it only works on natural teeth. It will not work on any types of ‘false’ teeth such as dentures, crowns and veneers. We can advise you appropriately before you decide to undertake any treatment. Sometimes a patient may wish to replace crowns and undertake some teeth whitening in advance of this so that the new ceramics can be colour-matched to the lighter teeth.

If your dentures are stained or discoloured why not ask for them to be cleaned professionally?

Many people find that their teeth and gums feel cleaner after they have been whitened. The whitening treatment was first used as a treatment to help heal gums, so this is an added benefit.

You can help to keep your teeth white by cutting down on the amount of food and drink you have that can stain your teeth. Don’t forget, stopping smoking can also help prevent discolouration and staining.

We recommend the following to care for your teeth:

  • brush your teeth for two minutes, twice a day with a fluoride toothpaste.
  • cut down on how often you have sugary foods and drinks.
  • visit your dentist regularly, as often as they recommend.


My experience at the Guild Practice has always been a very positive one. The dentist has always been very supportive and reassuring especially when I am anxious and nervous about treatment.
The plans for treatment are always fully explained and during treatment, the dentist will talk through each step which is very helpful.
I would really recommend the Guild Practice

Anne Mulvenna. Read more testimonials here.

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