Joe_NoOne quotes a report from Gizmodo: Flossing may not yield the protective benefits we've been told to expect. Since 1979, the federal government in the U.S. has recommended daily flossing, but by law these dietary guidelines, which are updated every five years, have to be supported by scientific evidence. Surprisingly -- and without any notice -- the federal government dropped flossing from its dietary guidelines this year, telling the Associated Press that "the government acknowledged the effectiveness of flossing had never been researched, as required." AP national writer Jeff Donn reports: "The two leading professional groups -- the American Dental Association and the American Academy of Periodontology, for specialists in gum disease and implants -- cited other studies as proof of their claims that flossing prevents buildup of gunk known as plaque, early gum inflammation called gingivitis, and tooth decay. However, most of these studies used outdated methods or tested few people. Some lasted only two weeks, far too brief for a cavity or dental disease to develop. One tested 25 people after only a single use of floss. Such research, like the reviewed studies, focused on warning signs like bleeding and inflammation, barely dealing with gum disease or cavities. Wayne Aldredge, president of the periodontists' group, acknowledged the weak scientific evidence and the brief duration of many studies...Still, he urges his patients to floss to help avoid gum disease. 'It's like building a house and not painting two sides of it,' he said. 'Ultimately those two sides are going to rot away quicker.'"