In the lab, scientists have found that flossing does indeed reduce inflammation and bleeding of the gums, indications that it could theoretically head off gum disease. Theoretically. But these studies only lasted a few weeks, not nearly enough time to track the development of long-term disease.
What you really need to prove the efficacy of flossing is a real-world, longitudinal study. “But when you move the study out into the real world, a large epidemiological study,” says Tim Iafolla of the National Institute of Dental and Craniofacial Research, “the problem is you can’t follow people at home and make sure they’re flossing correctly or flossing when they should be.”
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