Ask the Dentist: What should I use to make my teeth whiter?

While purple toothpaste might work for some people for a short time, there's science behind effective long-lasting tooth whitening, says Lucy Stock of Gentle Dental Care in Belfast

Talk to your dentist if you are trying to achieve a snow-white smile.
Talk to your dentist if you are trying to achieve a snow-white smile.

I'M not sure if it is by chance but my team all happen to be bubbling over with artistic talents.

One of our nurses, in her spare time, creates spectacular cakes. We were discussing the recent rise in popularity of the new purple toothpastes, like Hismile V34 colour corrector, and she explained that the same colour concept is used in baking.

The colour wheel, which looks like a circular rainbow, is where the colours are arranged in order of their complementary hues. And on this wheel, yellow and purple are diagonally opposite each other which leads to the optical effect of cancelling each other out when they are combined. My nurse adds a drop of violet food dye into her yellow buttercream to make it pristine white – who knew?

These toothpastes do work, though they have a very superficial short-lasting effect. Like any whitening toothpaste, its effectiveness depends on the condition of the teeth that they are applied to.

Take smokers for example. Over many years of smoking your enamel inhales the grey smoke and the teeth gradually turn grey themselves. It's super ambitious of any whitening product to tackle these intense ashen tones.

The other group of people who aren't going to have much success with any form of whitening are the tooth dissolvers who have worn the enamel away by eating acidy foods. The underlying dentine is yellow and notoriously difficult to whiten unless covered with a veneer or crown. These types of situations probably explain the almost 50/50 split between good and bad purple toothpaste reviews.

Peroxides are the traditional tooth-bleaching agents in whitening gels. They work by breaking down the bonds of stain molecules that have become trapped deep inside the enamel. The smaller molecules are less able to absorb light and thus we see whiter teeth.

In the Hismile range, they use a new novel ingredient called phthalimidoperoxycaproic acid (PAP). PAP works in the same sort of way as peroxides, it is effective, and studies are showing that it may be kinder on the teeth.

So, if you are struggling to achieve white teeth ask your dentist, as you may need different treatments before you can boast a snow-white smile.