The long-held view that eating too many sweets during childhood causes dental problems later in life is a myth, North-East scientists have discovered.

They found that the relationship between childhood and problems with teeth and gums diminished with increasing age and eventually became almost insignificant.

Adults who smoked and those from more deprived social backgrounds were more likely to suffer tooth loss, the study revealed.

Dr Mark Pearce, from Newcastle University, said: "These findings demonstrate that it is just as important for adults to look after their teeth and gums as children, and that good oral healthcare habits should not stop when people leave their family home."

The findings, published in the Journal of Dental Research, suggested that dental health campaigns should target adults as well as children.

They may also provide additional justification for recent Government initiatives to move away from disease treatment and towards more prevention.

Dr Pearce and his team studied data collected during childhood and at age 50 from more than 300 people taking part in the Thousand Families Study. They found that the more cigarettes someone smoked, the more teeth they were likely to lose.

In addition, an underprivileged background was frequently associated with poor oral health, such as infrequent brushing of teeth and irregular dental attendance.

Dr Pearce, who is director of the Thousand Families Study - a project that collected data from children born in Newcastle in 1947 - said: ''Damage to teeth and gums happens over a long period of time and is irreversible.

''Even if people are not used to following a toothcare regime, it's never too late for them to start.

''They can't turn the clock back but they can increase their chances of maintaining a good set of teeth into their old age - something which is very significant when you consider life expectancy is increasing all the time."

Research team member Professor Jimmy Steele said: "Even people who look after their teeth when they are children may slip into bad habits when they leave home.

"It's common for chocolate bars to be substituted for meals, or for regular teeth brushing to stop.

''In fact, studies show that men aged 20 to 30 are the worst at looking after their oral health.''