For decades, the federal government — not to mention your dentist — has insisted that daily flossing is necessary to prevent cavities and gums so diseased that your teeth fall out.

Turns out, all that flossing may be overrated.

The latest dietary guidelines for Americans, issued by the Departments of Agriculture and Health and Human Services, quietly dropped any mention of flossing without notice. This week, The Associated Press reported that officials had never researched the effectiveness of regular flossing, as required, before cajoling Americans to do it.

In a statement issued on Tuesday, the American Academy of Periodontology acknowledged that most of the current evidence fell short because researchers had not been able to include enough participants or “examine gum health over a significant amount of time.”

The revelation has caused a stir among guilt-ridden citizens who strive to floss daily but fall short of that lofty goal. Among experts, however, it has been something of an open secret that flossing has not been shown to prevent cavities or severe periodontal disease.