Dangerously high levels of common tooth-whitening agents can lead to 'extensive' tooth damage, it has emerged.
While at-home solutions sold online may appear cheaper, easier and quicker, they often contain alarming levels of hydrogen peroxide – a key whitening agent.
In the UK, over-the-counter whitening products can legally only contain 0.1% hydrogen peroxide.
Now, a team have looked at how peroxide penetrates tooth enamel and dentine before reaching the dental pulp, analysing the damage it causes.
An application of just 10% carbamide peroxide gel on teeth (a combination of hydrogen peroxide and urea) can reduce enamel protein by up to 50%.
And when concentrations of around 35% were used – a level seen in some products sold online – the researchers found dental pulp cells did not survive the exposure.
'Many home tooth-whitening products have such a high concentration of peroxide gel—for example, 35%. Yet, little is known about what it does to the inside of our teeth,' said Laurent Bozec, who led the study.
'We believe this is the first study of its kind to show the toxic effects of using a tooth-whitening agent. Our hope is that people will opt for a lower concentration of peroxide if they decide to use a tooth-whitening product as they are so much less harmful to your teeth.'
Carried out by the University of Toronto, findings suggest that using lower concentration levels of peroxide – such as 5% – is far less harmful.
The study shows the need for a compromise between the concentrations of peroxide used, exposure time, desired patient outcomes and side effects experienced.