Teeth whitening may be even more in demand after an oral healthcare expert pointed out that smiles are important to humans on a subconscious level.
Dr Charles Martin, founder of the Richmond Smile Centre in Virginia, cited research from the University of California which showed that the attraction of smiling is actually down to sound.
He explained that when people smile, their voice goes higher, which signals that they must be a small creature that does not mean harm, rather than a deeper-voiced animal such as a predator.
The expert added: "How does the world view us if we refuse to smile, even if that refusal is simply due to being self-conscious about a less than perfect smile?"
Something else which could increase demand for teeth whitening was a study by the University of Manchester, which found that men are drawn more to the mouth than any other facial feature on a woman.
