Stick to flossing: Hong Kong dentists insist on practice even as US health authorities admit to no proof of benefits

Hong Kong’s health authority and dentists are sticking to one of the most universal recommendations in all of public health – floss daily – despite the revelation that it is no longer recommended because there is little proof it prevents gum disease and cavities.

After promoting the practice for decades, the US federal government quietly dropped the flossing recommendation from its latest Dietary Guidelines for Americans released early this year, the Associated Press (AP) reported.

Floss furore: in a stunning dental backflip, the US government says medical benefits of flossing unproven

Upon the news agency’s request last year for evidence to justify the US government’s advocacy of flossing since 1979 – first in a surgeon general’s report and later in the dietary guidelines issued every five years – the federal administration admitted that the effectiveness of the method had never been researched. The AP focused on 25 studies, and concluded that the evidence was “weak, very unreliable”, of “very low” quality, and carried “a moderate to large potential for bias”.

Companies with a big market share of the flossing business also struggled to provide convincing evidence to support their claims that the practice reduced plaque or gingivitis. The industry was found to have funded most studies, even designing and conducting some research.

But Hong Kong’s Department of Health appeared unimpressed by the news yesterday.

“Dental flossing is part of good oral hygiene practice. Proper flossing can remove dental plaque from the adjacent surfaces of the teeth,” a spokesman said, adding that the department would continue to review developments related to the issue.

Oral health: how often should you go to the dentist’s?

Dr Sigmund Leung Sai-man, president of the Hong Kong Dental Association, said the issue was about flossing not being practised properly.

“There might be fewer than 20 out of 100 patients who floss ... and only two to three do it properly,” Leung said.

Local dentist Dr Nelson Wong Chi-wai agreed that floss was still effective to remove plaque – and prevent gum disease.

“A toothbrush cannot clean the plaque on surfaces between teeth, but floss can,” Wong said.