THERE is “weak evidence” that flossing prevents gum disease, according to a leading British dentist.

Professor Damien Walmsley, 58, of Birmingham University, said the time and expense required for reliable studies meant the health claims often attributed to floss were unproven.

Prof Walmsley, who is also a scientific adviser to the British Dental Association, said: “The difficulty is trying to get good evidence. People are different and large studies are costly to do. Until then you can’t really say yes or no.”

He said “more sophisticated trials” were needed.

An Associated Press investigation looked at the most rigorous research of the past decade. A total of 25 studies in leading journals found evidence for flossing is “weak, very unreliable”, of “very low” quality, and carries “a moderate to large potential for bias”.

Lancashire Telegraph dental expert Dr Aisha Ahmed recommended using interdental brushes rather than floss.

She said: “Flossing is okay if it is done properly. The majority of the population probably does not do it properly.

“If people do not do it properly it can traumatise gums.

“Interdental brushes are better than floss because they are less technique-sensitive so you cannot traumatise your gums.

“They will get rid of plaque or food which can get stuck between teeth and will remove it better than floss.

“The only thing I would add is if teeth are really tight and you cannot push the brush through, floss is an option, but it should be used really carefully.

“It’s a technique that needs to be shown so I ask your dentist or hygienist.”

One review conducted last year said: “The majority of available studies fail to demonstrate that flossing is generally effective in plaque removal.”

Another 2015 review cites “inconsistent/weak evidence” for flossing and a “lack of efficacy”.

Earlier this year, the US government dropped the flossing recommendation from its guidelines because they must be legally based on scientific evidence.