Floss and Interdental Brushes: Questions About Fit
Understand the general differences between floss and interdental brushes, the limits of the evidence, and questions to ask a dentist or hygienist about fit and handling.
Floss and interdental brushes are tools for cleaning between teeth. This guide explains general differences and provides questions for a dental visit. It does not assess your mouth, select a brush size, or prescribe care for gum disease, implants, braces, or another individual condition. A dentist or hygienist can assess fit and demonstrate an appropriate option.
How the tools may fit different spaces
The American Dental Association (ADA) gives floss for tight spaces and interdental brushes for more open spaces as examples of how tool choice can relate to a person’s characteristics. Interdental brushes come in different sizes to match spaces between teeth. These are general examples in U.S. professional guidance, not an assessment of your mouth or a recommendation of a specific size. Read the ADA’s guidance on dental floss and interdental cleaners.
The National Institute of Dental and Craniofacial Research (NIDCR) advises cleaning between teeth regularly, aiming for once a day. It lists floss and a special brush recommended by a dental professional among the options. NIDCR explains options for oral hygiene.
Handling matters, too
A tool’s fit is only part of the choice: it also needs to be manageable for you to use. NIDCR notes that arthritis or other issues can make floss difficult for some people, and lists aids such as floss holders and tiny interdental brushes. That information supports discussing dexterity and handling with a dental professional; it does not establish which option will be easiest for a particular person.
What the evidence can—and cannot—tell you
A 2026 paper reports recommendations from a roundtable of nine European experts, including clinicians and researchers. The meeting took place in 2023, and the paper generally favors interdental brushes while also discussing personalized recommendations. This is European expert consensus—not a U.S. guideline or a randomized head-to-head trial proving that brushes are best for every adult. Read the 2026 expert consensus paper.
A Cochrane review compared home-use devices for cleaning between teeth. It included 35 studies with 3,929 adults and searched for evidence through January 16, 2019. The review found that interdental brushes may reduce gingivitis more than floss at one and three months, but plaque findings were inconsistent. Overall, the evidence was low to very low certainty, the effects may not be clinically important, and most outcomes were short term. The review found no studies evaluating tooth decay and few evaluating severe gum disease. Its findings do not establish long-term prevention of tooth decay or periodontitis, and they do not include studies published after the search cutoff. See the Cochrane review and its evidence limits.
Questions to ask at a dental visit
- Which spaces between my teeth are tight, and which are more open?
- Could you show me an option that fits the spaces you’re assessing without forcing it?
- Could you demonstrate how to use the option you think may fit?
- Given my hand comfort and dexterity, what might be easier for me to handle? If floss is difficult, could we discuss a floss holder or another option?
A dentist or hygienist can discuss fit and demonstrate options. This article cannot determine your tooth spacing or recommend a specific brush size.
Key sources
- ADA: Flossing and Interdental Cleaning
- NIDCR: Oral Hygiene
- Cochrane review of home-use devices for cleaning between teeth
Editorial note: AI assists with research, drafting and automated checks. This is general education, not a personalized care plan or a claim of clinician review. It does not replace advice, diagnosis or treatment from a qualified healthcare professional. Sources are provided for verification; confirm details that apply to your care with your care team.
