Are interdental brushes more effective than dental floss?

The evidence suggests interdental brushes (IDBs) may have an edge over dental floss for reducing gingivitis, though overall certainty is low. A Cochrane review found low-certainty evidence that IDBs reduce gingivitis more than floss at one and three months, though evidence for plaque outcomes was inconsistent ^[1]. A withdrawn Cochrane review similarly reported low-certainty evidence of a 52% reduction in gingivitis (Eastman Bleeding Index) favouring IDBs over floss at one month, but found insufficient evidence to claim a benefit for either device for plaque reduction ^[2].

For plaque removal specifically, narrative evidence notes that studies have shown better plaque removal with IDBs compared to floss, though patient compliance with flossing is often poor - roughly one third of patients floss daily, and about one quarter reportedly lie to their dentist about their flossing habits ^[3]. A randomised trial around implant-supported crowns found both methods improved plaque control, though notably only the IDB group showed a statistically significant change in IL-6 levels ^[4].

It is worth noting that the overall evidence quality across comparisons is rated low to very low, and effect sizes observed may not always be clinically meaningful ^[1]. Device choice should also remain site-specific, as not all interdental tools suit every patient or anatomical situation ^[3].