Paris - Nearly 40 per cent of professional football players in Britain have rotted teeth, in some cases serious enough to affect performance on the pitch, according to a new study.

Footballers may make huge amounts of money, but little of it seems to go to dental care: on average, their teeth and gums are in worse shape than their British age peers, it said.

"We came across several players with tooth decay so deep that it was into the nerve and creating an infection in the jaw," lead author Ian Needleman of the UCL Eastman Dental Institute told AFP.

Many put off seeing a dentist despite tooth pain, he said, but whether this was due to a fear, bravado or a too-busy schedule was not clear.

The study, published in the British Journal of Sports Medicine, is the first to assess just how widespread dental problems are among pro footballers in England, and to what extent they affect athletic prowess.

Needleman led dentists and doctors in examining 187 players at eight clubs in England and Wales.

Five of the teams were in the Premier League: Hull, Manchester United, Southampton, Swansea City and West Ham.

Two were in the second-tier Championship league, and another in League One. The average age of players was 24, ranging from 18 to 39.

At least 90 per cent of players in each squad were examined and questioned about their health.

Thirty-seven per cent had active tooth decay, the researchers found, and more than half had teeth eroded by acid.

Eight in 10 players had gum disease, with half the mouth affected in three out of four players.

For one in 20, damage to the gums was irreversible.

Nearly three quarters of the players said they had seen a dentist in the preceding year, though physical examinations suggested many were less conscientious than claimed.

"I think they were aware (of the decay), but for various reasons were putting off treatment," he said by phone.

About one in six reported pain in their mouth or teeth at the time of the interview, and one in four said their teeth were sensitive to hot or cold drinks.

Nearly half the footballers said diseased teeth and gums "bothered" them, and a fifth said it undermined their quality of life.

'Debilitating and painful'

Seven per cent said the poor state of their dental health adversely affected performance or training.

"We also found players with wisdom tooth infections, which can be extremely debilitating and painful," Needleman said.

If left untreated, the worst cases "will stop someone from training completely, or take someone out of a game."

Arsenal striker Robin van Persie and Chelsea winger Florent Malouda have been reported as saying that having their wisdom teeth pulled some years ago improved their health and football acumen.

Surprising, very few clubs -- despite the huge investment they make in players -- have staff dentists, the researchers observed.

"Teams are beginning to recognise this as a priority," Needleman said.

"Successful strategies to promote oral health within professional football are urgently needed."

The study noted that nearly two-thirds of the athletes in the study consumed sugary sports drinks three times or more per week, though no link has been proven with oral decay.