A person's teeth may influence whether they will be successful in life, say a team of social psychologists.
People rate whitened teeth as more attractive
Researchers from King's College London found volunteers rated the same individuals less favourably when their mug shots showed visible tooth decay.
Those with rotten teeth were deemed less clever, less popular and less well adjusted - as were crowded teeth.
In comparison those with whitened teeth were rated as more attractive and successful than normal.
Professor Tim Newton who carried out the research said: "I would have thought that people would prefer natural looking teeth, but actually they don't."
FAMOUS PEOPLE WITH 'TRADEMARK' TEETH
Comedian Ken Dodd
Lead singer of Queen Freddie Mercury
Lead singer of the Pogues Shane McGowan
Writer and broadcaster Janet Street-Porter
DJ turned actor Goldie
The difference was even greater when the pictures were of women, suggesting people judge women more than men based on looks alone.
Yet, there are many famous people who have achieved success with less than perfect smiles, he said.
For some, such as Ken Dodd, their gnashers are their trademarks.
Indeed DJ turned actor Clifford Prince or "Goldie" got his nickname after living in Miami earning a living making and selling gold tooth caps.
But other celebrities strive for the perfect smile and have cosmetic dental procedures such as bleaching or caps.
Actors Tom Cruise and Cary Grant both had one of their front teeth missing. Tom has since had his corrected.
Professor Newton said his studies suggested that people who were already above average in attractiveness stakes stood a better chance of carrying off a less than perfect smile than people who were not so naturally attractive.
"If you are attractive and you have a bit of decay you can probably get away with it."
But people who are not classically beautiful may have other attributes that make up for it, such as an outstanding wit, he said.
It also appears that people's expectations about what makes a beautiful smile have changed.
Professor Newton said people today associate perfectly straight, white teeth with beauty because of the Hollywood images they see in magazines and on TV.
In the 100 or so volunteers he tested, he found when people had been looking at pictures of others with these so-called "perfect smiles" they were likely to be less satisfied with their own facial appearance as a result.
In the future, he said it would be interesting to investigate how the attitude differences he found in his studies might impact on peoples' lives.
"For example, if you had two identical people going for the same job, but one had worse teeth than the other, would he be less likely to get the job?" he asked.
Professor Jimmy Steele, a consultant dentist at Newcastle University, said: "If you went back even 10 years ago, footballers often had bad or even no teeth. Now footballers have dental makeovers.
"It's changed the general public's expectations substantially and what we perceive as normal."
Indeed, manufacturers of porcelains and other dental materials used to make artificial teeth have had to produce new whiter shades to match these trends and expectations.
Professor Steel added: "In some ways it is quite positive because it encourages people to look after their teeth."
But he said expectations could be unrealistic and might detract away from the fundamental aspects of healthy dentition - people focusing on what looks good rather than what makes for a healthy smile.
He said it was also putting pressure on dental services.
"It has major implications for the health service. It's generating a demand that can only be partially met.
"I see people every week in my clinic who want something done to improve the appearance of their teeth, and it's not just young people.
"I recently had an 82-year-old lady who wanted orthodontic treatment to straighten her teeth, which is something that we would normally do on 13-year-olds."