Canada’s top dental association hasn’t changed its stance on flossing after an in-depth U.S. investigation found little proof that it actually works, but there is some wiggle room for daily oral hygiene practices.

In a report published Tuesday, The Associated Press cited 25 studies that found evidence for flossing is "weak, very unreliable" and of "very low" quality. The U.S. government acknowledged that its support for flossing wasn’t backed by sufficient research, and it quietly removed flossing from the dietary guidelines this year.

In Canada, the Canadian Dental Association’s official stance on flossing is that it is an effective way to remove plaque and bacteria between teeth that a toothbrush can’t reach. But the organization’s president-elect said every patient is different and several tools can get the job done.

“If patients say, ‘I know flossing is good for me but I just can’t seem to get it into my routine,’ then talking to them about using one of the little inter-dental cleaners -- like a toothpick -- for cleaning between the teeth will do a great deal of the same job that flossing will do,” Levin told CTV News.

“But there is no study that has shown leaving plaque on your teeth is beneficial for good oral health. On the contrary, every study has shown the need to remove plaque in order for your teeth and gums to be healthy.”

Levin also called for more research to explore the efficacy of flossing. Until that happens, he says, flossing remains a useful tool.

“If in the future we find there is a better way of doing it, then all of the dentists across Canada are going to be the first people to suggest we have a better way, a newer way, then let’s adopt that technique,” he said.

“If we haven’t got another tool to suggest, I would never suggest changing what we now are using to prevent cavities in that regard.”

Quality of flossing 'hard to monitor'

The AP report came as a surprise to the former vice-president of the Royal College of Dental Surgeons of Ontario.

“I’m actually quite shocked about it, and I can tell you as a dental professional, flossing is key. We often say in the office, floss the teeth that you want to keep,” dentist Natalie Archer told CTV News Channel on Tuesday.

Archer said it’s obvious to dentists when a patient hasn’t been flossing. She said she’ll continue to endorse flossing and raised questions about how a proper flossing study should be conducted.

“I’d love to see the studies in closer detail. Because flossing is one of those things that I would think would be very hard to monitor in terms of doing a flossing study,” she said.

“How I would floss my teeth would be very different probably than the average person or public or patient out there. In fact, if we’re not flossing properly or in a C-shaped manner, we may be flossing but not flossing properly for it to be effective.”

In terms of patient-dentist relationships, the news has some dentists worried that it could be trickier to convince patients to floss.

“That’s a big uphill battle already as it is,” Vancouver-based dentist Dr. Ehsan Taheri told CTV Vancouver. “So I think it’s going to be giving them an extra excuse not to.”

But Levin said the AP investigation has begun “a wonderful discussion” that appropriately challenged the status quo in dental hygiene.

“I think information questioning what is being done is wonderful for everyone because anytime you do something as a matter of routine, I think that you lose interest in it and you lose understanding on its benefits,” he said.

How to floss

The proper flossing technique, according to the Canadian Dental Association, begins with a piece of floss the length of a person’s hand to their shoulder. The floss should be wound around the index and middle finger with about two inches of space between. Each tooth should be cleaned by wrapping the floss in a C-shape around the base of the tooth and sliding the floss from base to tip two or three times.

Teeth should be brushed after flossing, according to the guidelines.

Bleeding is a common side effect when a person begins flossing, but it should stop after a few days. If it does not stop, the Canadian Dental Association recommends visiting a dentist.

With files from the Associated Press