Floss, interdental brushes or a water flosser?
How to clean between your teeth: floss technique, interdental brush sizes, water flossers, what the evidence shows, and tips for braces and implants.
Written by the Glowpedia team · not yet reviewed by our dentist
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Quick answer Clean between your teeth once a day, because a toothbrush can't reach there. Floss suits tight gaps, interdental brushes suit larger gaps and may reduce gum inflammation more than floss, and water flossers help with braces, bridges, implants or stiff hands.
Why clean between your teeth
Brushing cleans the front, back and top of each tooth, but not the tight surfaces where teeth touch. Plaque left there can inflame your gums and lead to decay. The American Dental Association and the NHS advise cleaning between your teeth once a day, on top of brushing twice a day.
The research has limits. A 2019 Cochrane review of 35 trials with nearly 4,000 adults found that adding floss or interdental brushes to brushing may reduce gum inflammation, and that interdental brushes may do slightly better than floss. The evidence was low certainty and mostly short term, but these tools are cheap and safe, so dentists still recommend them.
Which tool for which mouth
| Tool | Best for | Watch out for |
|---|---|---|
| String floss or tape | Tight contacts, small gaps | Takes practice and some dexterity |
| Floss picks | Beginners, quick use | Rinse the pick between gaps; use a new one each time |
| Interdental brushes | Larger gaps, gum recession, bridges | You need the right size for each gap |
| Water flosser | Braces, implants, bridges, stiff hands | Weaker evidence for removing plaque |
Many people mix tools: floss at the front, small brushes at the back.
How to floss
- Break off about 18 inches (45 cm) and wind most of it around one middle finger, the rest around the other.
- Hold 1–2 inches (3–4 cm) tight between your thumbs and forefingers.
- Ease it between teeth with a gentle rubbing motion. Don't snap it into the gum.
- Curve it into a C shape against one tooth and slide it gently just under the gumline. Move it up and down a few times, then do the same on the neighboring tooth.
- Use a clean section for each gap, and don't forget the back of the last teeth.
Mild bleeding in the first days is common when gums are inflamed, and it usually eases within 1–2 weeks of daily cleaning. Bleeding that doesn't stop needs a dental check; see gum health.
Interdental brushes and water flossers
- Interdental brushes: pick the largest size that slides in without forcing. Most people need 2–3 sizes, and a hygienist can measure your gaps. Move the brush in and out a few times, rinse it, and replace it when the bristles flatten or the wire bends.
- Water flossers: fill with lukewarm water and start on the lowest setting. Lean over the sink, aim the tip at the gumline and trace along each gap, pausing briefly between teeth. A full mouth takes about 1–2 minutes.
- Skip wooden toothpicks for daily cleaning; they can damage gums.
Braces, bridges and implants
- Braces: use a floss threader or floss with a stiff end to get under the wire, small interdental brushes around brackets, or a water flosser.
- Bridges: thread floss under the false tooth, or use a water flosser.
- Implants: use interdental brushes with a plastic-coated wire, floss made for implants or a water flosser, as your dentist shows you.
Before or after brushing?
Either is fine as long as you do it every day. The NHS suggests flossing before you brush, and the ADA says the order doesn't matter if you're thorough. Then brush as usual; see how to brush your teeth properly. Clean gaps also help prevent bad breath.
What you need for this
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See a dentist if your gums bleed for more than 2 weeks despite daily cleaning, if floss keeps shredding or catching on one tooth, or if the gaps between your teeth are getting bigger. A hygienist can show you the right tools and brush sizes for your mouth.
Questions people ask
Is flossing really necessary?
A toothbrush doesn't reach between teeth, so dentists advise cleaning there once a day. Floss is one option; interdental brushes or a water flosser are reasonable alternatives.
Can a water flosser replace floss?
For people with braces, implants, bridges or stiff hands, it's a good option. For most others it works best as an extra, because floss and interdental brushes have somewhat stronger evidence for removing plaque.
Why do my gums bleed when I floss?
Usually because they're inflamed from plaque. Keep cleaning gently every day; bleeding often improves within 1–2 weeks. If it doesn't, see a dentist.
Waxed or unwaxed floss?
Both work equally well. Waxed floss or tape often slides more easily between tight teeth.