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Floss or interdental brushes: which to use

Floss or interdental brushes for cleaning between teeth? Here is how they differ, who each suits and how to ask your dentist which size or type is right.

Sofia Benyahia3 min read

A roll of dental floss and small interdental brushes laid on a white towel
Image by muklinika from Pixabay

Verdict: floss and interdental brushes do the same job, cleaning the gaps your toothbrush cannot reach. The better one is the one that fits your gaps and that you will actually use each day. The NHS advises cleaning between your teeth daily, as part of a routine with fluoride toothpaste.

Which wins on

QuestionFlossInterdental brush
Best forTight gaps between teethWider gaps, or gaps with some space
EaseTakes a little practiceOften easier to hold and use
SizingOne sizeComes in sizes, so fit matters
Around braces or bridgesNeeds a special threaderOften handier, if the size fits
CostUsually lowUsually low, but sizes add up

Pick floss if

  • Your teeth are close together and a brush will not fit
  • You are comfortable using it, or willing to learn
  • Your dentist suggests it for a certain area

Pick interdental brushes if

  • Your gaps are wide enough for a small brush
  • Floss is hard for you to hold or control
  • You have bridges, braces or other work, and your dentist advises it

Decision rule

If a brush fits the gap with a gentle push, it is a good option. If you have to force it, use floss or a smaller size. Never force either into a gap.

A close view of a small interdental brush beside a toothbrush
Sizes are colour coded, so ask which one you needImage by stevepb from Pixabay

How do I find my size?

Ask your dentist or hygienist to show you. Many clinics will check your gaps and name the sizes. Sizes differ by maker, so write down the number or colour and the maker's size chart. Gaps in different parts of the mouth may need different sizes.

What mistakes are common?

  • Forcing a brush that is too big
  • Snapping floss against the gum instead of sliding it
  • Skipping the back teeth
  • Giving up after a few days because gums bleed a little at first. If bleeding keeps on, tell your dentist, since it can be a sign to check your gums. See the NHS page on gum disease and ask a dentist about your own case.

What about water flossers?

Some people use water flossers. Ask your dentist whether they would suit you and how to use them with, not instead of, other cleaning.

Caution

If you have sore, swollen or bleeding gums that do not settle, or a loose tooth, see a dentist rather than trying new tools. Our page on how often you should see a dentist explains how the gap between visits is set, and electric or manual toothbrush covers the brush itself.

General information, not advice for your teeth.

Quick questions

Is brushing enough on its own?

The NHS advises cleaning between teeth too, because a toothbrush cannot reach every gap.

How often should I clean between my teeth?

Daily is the usual advice. Ask your dentist what suits you.

Can children use these?

Ask a dentist about what suits a child's teeth and age.

Which one is better for braces?

Ask your orthodontist. See braces or clear aligners for questions to ask.

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