Interdental brushes (IDBs) are increasingly recommended as an alternative to traditional floss for cleaning between teeth.

Research comparing the two focuses on how well they remove plaque from interdental spaces and how effectively they improve gum health and reduce bleeding.

What the evidence shows

• IDBs tend to improve gum health slightly more than floss in the short term, with more consistent reductions in gum inflammation scores.

• Small reductions in bleeding sites are more often seen with IDBs than floss in clinical trials.

• Plaque findings are less consistent – some studies show better plaque removal with IDBs (especially where spaces allow brush access), while others show little difference.

• Benefits appear greater in people with gum disease or open interdental spaces, where brushes can physically contact more tooth surface.

• Technique and regular use matter a lot. In unsupervised “real-world” studies, differences between tools can shrink if people don’t use them effectively.

• Overall, IDBs generally outperform floss for gum health outcomes, but the size of the advantage is modest and the certainty of evidence is often low.

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Major systematic review & meta-analysis

Systematic review (2019) - Cochrane Library

• IDBs tend to improve gum health slightly more than floss in the short term, and may lead to small reductions in bleeding.

• Plaque results between IDBs and floss is less consistent.

• Overall, the advantage exists but is modest, and the exact size of the benefit is uncertain.

View study on Cochrane Library

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Other studies

Meta review of interdental cleaning on plaque control (2015) - Journal of Clinical Periodontology

• Found the evidence supporting floss for gingivitis reduction to be weak, with no convincing plaque effect across the floss evidence reviewed.

• Concluded there is moderate evidence that IDBs used alongside toothbrushing can reduce both plaque and gingivitis, and that IDBs appear among the most effective interdental methods for plaque removal.

View the study in the Journal of Clinical Periodontology

Meta analysis of oral hygiene methods on inflammation (2018) - Journal of Periodontology

• Ranked IDBs as the most likely “best” option for Gingival Index reduction (highest probability in the ranking framework).

• Ranked floss very low (near-zero probability of being “best” in their model).

View the study in the Journal of Periodontology

Comparison of different interdental aids (1998) - Journal of Periodontology

• IDB use led to greater plaque removal than floss used on the contralateral side, alongside a slightly larger probing depth reduction.

• Differences were described as small, but patient preference tended to favour the easier method (IDB).

View the study in the Journal of Periodontology 

Single-blind parallel RCT in chronic periodontitis (2006) - Journal of Periodontology

• Both groups improved significantly, but interdental brushing produced greater improvements across multiple parameters at 6 weeks.

• By 12 weeks, improvements in plaque and probing depth remained significantly greater in the IDB arm.

View the study in the Journal of Periodontology 

Comparative study on interdental plaque control aids (2006) - Oral Health and Preventive Dentistry

• All tools reduced plaque after use, but IDBs produced markedly lower final plaque scores than floss in interdental spaces.

View the study in PubMed

A comparison of floss and interdental brushes (1991) - Journal of Clinical Periodontology

Mean gingival and plaque scores were lowest with toothbrush + IDB.

• Proximal plaque outcomes tended to favour IDB over floss.

View the study in the Journal of Clinical Periodontology

Comparing the effects of different interdental cleaning aids (2024) - Compendium of Continuing Education in Dentistry

• Improvements in gingival inflammation were small and similar for floss (~2.8%) and IDB (~2.6%) when used unsupervised at home.

• Suggests real-world outcomes can be dominated by technique and adherence, rather than device category alone, especially in more inflamed populations.

View the study in PubMed

Evaluation of the efficacy of interdental brush and dental floss for peri-implant mucositis: A crossover randomized clinical trial (2024)

• Both IDB and floss reduced plaque and gingival indices after two weeks.

• IDB appeared most effective overall, while floss performed better mainly among participants with better manual dexterity.

View the study in the International Journal of Dental Hygiene