TUESDAY, Aug. 2, 2016 (HealthDay News) -- Your mom told you to floss from an early age, and you try your best to keep up the habit because it saves gums and teeth.
Or does it? A new investigation by the Associated Press suggests there's no good evidence backing up the claim that flossing is good for you.
The AP looked at data from 25 studies conducted over the past decade. The studies generally compared the use of a toothbrush alone with combined use of a toothbrush and floss.
Those studies concluded the evidence for flossing is "weak, very unreliable," of "very low" quality, and carries "a moderate to large potential for bias."
One review went further, saying that the "majority of available studies fail to demonstrate that flossing is generally effective in plaque removal," the AP reported. Another said there was only "inconsistent/weak evidence" for flossing and a "lack of efficacy."
The findings fly in the face of accepted wisdom on dental health. For decades, dental groups, floss manufacturers and other organizations have urged people to floss. And since 1979, the U.S. government has recommended flossing, first in a surgeon general's report and then in the Dietary Guidelines for Americans released every five years.
However, under the law, those guidelines must be based on scientific evidence, according to the AP.
But after the AP asked for evidence, the federal government admitted there was no research supporting the effectiveness of flossing, the news agency said.
The scientific evidence for flossing is weak, said Dr. Wayne Aldredge, president of the American Academy of Periodontology (AAP). However, he told the AP the benefits of flossing might be clearer if studies focused on people with the highest risk of gum disease, such as smokers and diabetics.
Aldredge said he still encourages his patients to floss. But he thinks many people don't floss correctly, because they move the floss in a sawing motion instead of up and down the sides of their teeth.
When asked about the AAP's promotion of flossing, Aldredge told the AP that the periodontal group may simply have followed the lead of the American Dental Association (ADA), which has recommended flossing since 1908.
And when asked for its evidence supporting flossing, the ADA cited one 2011 study review that did suggest flossing slightly reduced the risk of gum inflammation, which can develop into gum disease.
However, the authors of the new review called the evidence from that study "very unreliable."
The ADA also pointed to a 2008 two-week study that focused on bacteria but did not consider gum disease, the AP said.
One dentist said a new look at the evidence around flossing can't hurt.
"I support the concept of taking a new look at the evidence that has served as the basis of our clinical practice and making changes if evidence supports making such a change," said Dr. Ronald Burakoff, chair of the department of dental medicine at Northwell Health in New Hyde Park, N.Y.
In a statement, the ADA said that flossing "removes plaque" and "is proven to help remove" debris from between teeth. ADA spokesman Matthew Messina did acknowledge that there's only weak evidence for flossing, but said that was due to study participants who didn't floss correctly.
Floss manufacturers partner with the ADA through its Seal of Acceptance program. The ADA charges each manufacturer $14,500 to evaluate a floss product. If the ADA approves the product, it then charges the company an additional annual fee of $3,500, the AP reported.
The ADA said it makes no profit from the program, which permits floss manufacturers to design the studies.