Professional whitening

Dentists use custom-made trays or in-surgery bleaching to whiten deeply stained teeth.

Your dentist should start by asking about your medical history to find out how your teeth became discoloured as different types of stains will respond differently to the treatment. Your teeth will be checked and any cavities or cracks will be repaired.

Is it worth it?

We asked members about their experiences of professional whitening.

Custom-made trays

Overall, people were pleased with the results from custom-made trays:

• "Found it very successful. Only needed five or so nights"
• "The effects lasted quite some time - many months"
• "Good results but sensitivity increases hugely".

Depending on the bleaching product used, you wear the trays either overnight or for a short period twice daily. The overnight option is more effective - but you're more likely to feel sensitisation (although the dentist can give you a desensitising gel to alleviate this). The treatment usually lasts 10 to 21 days.

You need to have a preliminary consultation to examine your teeth and take impressions for the trays.

In-surgery bleaching

Those who had had in-surgery bleaching were less satisfied. For this treatment the dentist cleans your teeth, paints a resin over your gums to protect them, and paints a concentrated gel on your teeth. An intense light is then shone on your teeth to activate the bleach. The session takes around 60 to 90 minutes.

Most felt it wasn't good value for the money they paid:

• "It was expensive, time-consuming, boring and not terribly effective"
• "My teeth went three to four shades lighter - but I would only do it if I had money to burn"
• "I wouldn't recommend it for a smoker like me".

Some dentists provide a take-home tray and gel.

Non-vital whitening

Non-vital whitening is used to treat a single tooth which has darkened after an accident or root canal work. The dentist drills into the tooth, places whitening agent inside and reseals it. One member found that the improvement was only temporary - a crown was the best solution.

Safety

Dentists can use higher concentrations of bleach because they can control your exposure to it and check the health of your teeth and gums.

Teethwhitening products that contain more than 12 percent hydrogen peroxide will be tightly controlled from June 2013. 

Only dentists and registered oral health practitioners supervised by a dentist will be allowed to sell these products and treatment must be carried out by a dentist or under a dentist's supervision.  

The bottom line

Bleaching at the dentist's gives the best results - it can lighten the colour of teeth by several shades. It's most likely to be successful where discoloration is light or evenly distributed (without dark bands or patches). It works well on yellow teeth and on brown stains, but blue-grey stains caused by tetracycline may not lighten as much as the surrounding enamel. This can make such staining appear worse than before. (See What causes staining? for more on types of stains.)

Bleaching won't work on tooth-coloured fillings, veneers, or crowns.