Smile! Scientists work out the secret to the perfect teeth

By JAMES MILLS

Last updated at 17:36 26 November 2007


A dazzling white smile might be essential for Hollywood stars.

But those glow-in-the-dark teeth

aren't right for most people,

according to scientists who have

worked out a formula for the perfect smile.

They took several factors into account,

including the size and width of each

tooth, the curve, colour and shape of the

teeth and the overall width of the

mouth.

As far as colour is concerned, they

concluded that bright white should be

avoided. Instead, they said, the whiteness

of the teeth should match the

whites of the eyes, otherwise the smile

stands out too much and detracts

from the rest of the face.

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perfect smile

"One of the first things about

a smile people notice is the colour,"

said Dr Nicholas Davis, who led the

research.

"People are bleaching their

teeth and many times they do

it beyond what is natural.

"The teeth should be the same colour

as the whites of your eyes. If the teeth

are too white, they become more dominant than the eyes"

Dr Davis, of Loma Linda University

School of Dentistry in

Southern California, said Jessica

Simpson, who starred in

the 2005 film The Dukes Of

Hazzard, had most people's

idea of the perfect smile.

"Jessica Simpson is the one we

get asked to reproduce the

most," said Dr Davis, whose

study is published in the journal

Dental Clinics of North

America.

His formula boils down to a

set of mathematical ratios. A

smile's ideal width should be no

less than half the width of the

face and both upper and lower

lips should be symmetrical each

side of the mid-line of the face.

The top row of teeth should

be dominant while very little

should be seen of the bottom

row. All teeth on display should

be straight with no visible signs

of restoration work.

The teeth should diminish in

size from front to back. Those

either side of the central teeth, the laterals, should be 61.8 per

cent the size of the bigger teeth.

The next teeth along should be

61.8 per cent of the laterals. The

width of the central teeth

should be 80 per cent of their

height.

And to avoid a horsey smile,

very little should be seen of the

gums.

London-based dentist Oliver

Harman, whose clients include

Catherine Zeta-Jones, said people

should go for regular 'mouth

manicures' to remove stains,

but it was not necessary to

iron out all imperfections with

expensive cosmetic dentistry.

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