Teeth whitening: How does it work, how much does it cost and is it safe

The truth about teeth whitening: From how it works to how long it lasts and if teeth whitening kits are worth it

18th February 2024 | Author: Abigail Beall

We speak to the experts to discover how teeth whitening works, and more importantly if teeth whitening at home is worth it

When it comes to people’s biggest insecurities, research has found that more than half of us (51%) aren’t happy with our smile – and social media is one of the biggest contributors to this self-consciousness. This may explain why there are more than 110,000 searches each month for teeth whitening, and more than 40,000 for teeth whitening kits.

Of course, social media is not a true portrayal of reality. Selfies can be enhanced to make teeth look whiter, and even straighter. But when you’re bombarded with perfect-looking images, it is easy to forget this.

To discover how teeth whitening works, and more importantly, if teeth whitening at home is actually worth it , we spoke to Guy Barwell, dental surgeon and co-founder of The Implant Centre.

How does teeth whitening work?

There are three main ways to get whiter teeth – teeth-whitening gels, laser whitening and veneers.

Teeth whitening gels

Most professional whitening gels contain carbamide peroxide or hydrogen peroxide, which penetrate the enamel to reach the discoloured molecules inside the tooth. ​Oxygen molecules from the whitening agent react with the discoloured molecules in your teeth, breaking the bonds that hold them together.

“The overall whitening effect depends on the severity of the staining on the current teeth, and of course with professional whitening you will be able to notice a vast difference in terms of shade” Barwell told mamabella.

This method of whitening involves your dentist taking an impression of your teeth which they use to create a mouth guard and into which you will squeeze the whitening gel using a syringe. “You can wear these every other day from two-four weeks up to eight hours at a time for the best results but can be quicker depending on the original colour of the teeth” continued Barwell.

Some people’s teeth do become sensitive to the peroxide in these gels, though, and this means their teeth can start to ache or hurt when they consume hot or cold foods and drinks. “This potential side effect of teeth whitening is usually short-term, and goes away with time, but it’s always best to seek professional advice” says Barwell. If you do use whitening gels, avoid consuming particularly hot or cold products directly after whitening.

Laser teeth whitening

Getty Images/iStockphoto

The other teeth whitening option is laser ‘in-chair’ whitening at your dentist

The other option is laser ‘in-chair’ whitening at your dentist. “This works by having a bleaching product placed onto the teeth and then a laser is shone to activate the whitening” said Barwell.

“The treatment takes approximately an hour and is great if you have a wedding or function to attend but the effects tend to wear off quicker than doing at-home whitening over a period of time.”


“If you’re looking for ‘tippex’ white teeth, which look unnatural in appearance then this can only generally be achieved by veneers,” added Barwell.

Veneers help to enhance the shape, colour and position of your teeth through the use thin, translucent strips of composite resin material, or porcelain shells that are glued onto the front of the teeth using glue. They’re particularly useful for correcting chips and cracks, but can also help make teeth look whiter and straighter. They can even get mask the appearance of gaps between teeth.

FURTHER READING: The truth about teeth veneers and how they work, according to a leading aesthetic dentist

How much does teeth whitening cost?

Prices for the use of gels tend to vary, but Barwell said people should expect to pay anything from £400 up to £1,000.

Prices for laser teeth whitening start at around £1,000, while the price of veneers ranges from £150 per tooth right up to £1,000 per tooth, depending on which type of material you use.

How long does the effect last? 

How long teeth whitening lasts depends on several factors. Veneers tend to last longer, by default, due to their more permanent nature and the fact they’re made from a different material that’s less likely to stain. High-quality veneers that are well looked after should last between five and eight years.

At the opposite end of the scale, laser teeth whitening is the fastest way to get pearly whites but as a result, they’re also the most likely to fade within a matter of days, maybe weeks.

Teeth whitening gels are the most involved process of the three, and the results are less immediate, but this means that they will last longer. Unless, of course, you’re an avid coffee drinker, smoker or indulge in other activities that discolour your teeth.

Is teeth whitening safe?  

When carried out by a qualified professional, teeth whitening is safe and comes with few side effects.

Although the price of cheaper options might be tempting, they can often cause more problems down the line. “Many beauticians and self-employed individuals offer teeth whitening but this is currently illegal if there is no dental professional present and can cause sensitivity and oral health problems” explained Barwell.

“I also advise not being tempted by ‘cheap’ deals on teeth whitening offered from ‘voucher sites’ as, again, cheapest isn’t always best and you can end up paying more in the long run for the desired effect.”

Barwell also said to avoid the temptation of the cheaper ‘try at home’ kits, too.

Teeth whitening kits: Are they worth it?

“There are numerous teeth whitening options available on the high street from toothpastes, mouthwashes, mouth guards and whitening strips are just a few,” continued Barwell.

But the majority of these simply don’t work. This is because “home kits and unregistered individuals generally don’t have the professional level of peroxide for the whitening to be effective” continued Barwell. “The “at-home” kits, particularly ones with a one-size-fit-all mouth guard can cause the bleaching gel to leak out into the gum and cause sensitivity and blisters.”

We’re currently in the process of putting some of the more popular of these at-home teeth whitening kits to the test to see just how effective they are. 

If done correctly, treatments can have a dramatic impact on how you feel about your smile, and your overall confidence. But remember to always stay on the safe side, use a professional who you can ask if there’s anything you are concerned about.

Any dentist can whiten teeth if they are registered with the General Dental Council.

Barwell concluded that the most important thing for good-looking clean teeth is to perfect your brushing technique, because this helps get rid of surface stains, and get into a good routine for looking after your oral hygiene.

This means brushing your teeth for two minutes each morning and night, flossing every day and using interdental sticks to get rid of any trapped food.

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