We yearn to have smiles like Kylie Minogue, George Clooney or Simon Cowell according to research by the British Academy of Cosmetic Dentistry (BACD).

In reality a third of us are "concerned about the look of our teeth" while a fifth of people are so embarrassed by less-than-perfect gnashers that they usually conceal them in photos.

National Smile Month (May 18-June 17) is almost upon us and Dr David Bloom, dentist and president of the BACD, said: "Our research found that people nowadays put a very high value on a good smile."

And it is not just confined to the affluent south. Over a quarter (26 per cent) of Northerners have had cosmetic dentistry, not far behind the (28 per cent) of Londoners who splurged on similar procedures. Almost half (47 per cent) of Northerners feel cosmetic dentistry could improve their smile, compared with 35 per cent of Scots.

However, while cosmetic dental whitening accounts for more than 30 per cent of dental procedures, there are perils. Choose the wrong method, warn dentists, and you can permanently damage teeth by dissolving the delicate enamel coating, harm gums or find teeth become hyper-sensitive to changes in temperature caused by hot or cold drinks.

Dr Uchenna Okoye, a board member of the BACD and dentist on the new series of Channel 4's 10 Years Younger, says: "A beautiful smile is key to a good appearance be-cause when people meet us for the first time they focus on our eyes and smile.

She, in common with many dentists, had her own teeth whitened – surveys have shown that on healthy teeth it does no damage – but she emphasises the need to seek advice and treatment from a professional dentist.

"Sadly, some patients come to me for help because they are experiencing pain and problems after perhaps having treatments done by unqualified people in beauty salons, going abroad to get so-called bargain treatment or using a cheap DIY whitening kit they've bought over the internet."