Cleaning Between Your Teeth

Key takeaways

Clean between your teeth once a day, as well as brushing twice a day.
Interdental brushes, floss and water flossers all work; the best one is the one you will use every day.
Interdental brushes suit larger gaps; floss suits tight gaps. Many people use both.
Gums may bleed at first. Do not stop: bleeding often settles with regular, gentle cleaning. If it does not, see a dentist.
Avoid wooden toothpicks and improvised objects, which can damage your gums.

Brushing cleans the front, back and chewing surfaces of your teeth, but not the narrow spaces between them. The American Dental Association says even the best toothbrush cannot fully clean these spaces. Plaque (the NHS describes it as a film of bacteria that coats your teeth) builds up there and just under the gumline, and it contributes to gum disease and tooth decay.

Cleaning between your teeth is called interdental cleaning. Health bodies in the UK, Australia and the US all recommend it as part of a daily routine.

Why does it matter?

The NHS says gum disease is caused by a build-up of plaque, and that if you do not remove it by brushing and cleaning between your teeth regularly, it builds up and irritates your gums. The Oral Health Foundation says daily interdental cleaning helps prevent tooth decay, protect against gum disease and bleeding, and reduce bad breath. The American Dental Association adds that plaque left in place can harden into tartar (calculus), which only a dental professional can remove.

Floss, interdental brushes or a water flosser?

There are three main options. The Australian Dental Association lists string floss, flossettes (a small handle holding a short piece of floss), interdental brushes and water flossers.

What the research shows

A 2019 Cochrane review, which pooled 35 studies in 3,929 adults, found that:

using floss as well as a toothbrush may reduce gingivitis (inflamed gums, the early stage of gum disease) in the short and medium term
using an interdental brush as well as a toothbrush may reduce gingivitis and plaque in the short term
interdental brushes may be better than floss for gingivitis at one and three months
a water flosser (the review calls it oral irrigation) may reduce gingivitis in the short term, but there was no evidence of this at three to six months

The reviewers rated this evidence as low to very low certainty, said the effects may not be clinically important, and noted that no study measured tooth decay. So interdental cleaning is widely recommended, but research cannot yet say which method is best for everyone.

Choosing the right one for you

Interdental brushes look like tiny bottle brushes. The Oral Health Foundation says they are often easier to use than floss, especially where gaps are larger. The Australian Dental Association suggests them for people with braces, larger gaps, severe gum disease, or difficulty using floss.
Floss is useful for tight spaces where brushes may not fit, according to the Oral Health Foundation.
Water flossers spray a thin stream of water between the teeth. The American Dental Association says they can help if you find other tools hard to use, or if you have braces, bridges or other dental work. The Oral Health Foundation adds that brushes or floss can physically scrape plaque off the tooth, which water alone cannot always do, so it describes a water flosser as a useful extra rather than a replacement.

The Oral Health Foundation's advice is to choose the method you are most likely to use every day. Your dentist or hygienist can help you pick the right tool and size.

How to use interdental brushes

Ask your dentist or hygienist which size suits each gap. Spaces differ, so you may need more than one size.
Hold the brush between your thumb and forefinger.
Gently guide it into the triangle-shaped space between two teeth, with a slight twist, then push it through and pull it back.
Use light pressure. The bristles should fit firmly but comfortably. Do not force it: if it bends or splays, try a smaller size.
Rinse the brush as you go. Replace it when the bristles look worn or the wire is bent.

These steps combine advice from the Oral Health Foundation and the Australian Dental Association, which adds that you may need to gently curve the wire to reach the back teeth.

How to floss

Take about 30–45 cm of floss (the length suggested by the NHS and the Australian Dental Association) and wind it around a finger on each hand.
Hold it taut, leaving a few centimetres to work with.
Ease it between two teeth with a gentle rocking motion. Never snap it down onto the gum.
At the gumline, curve the floss into a C-shape around one tooth and gently slide it up and down, just under the gum edge.
Repeat on the neighbouring tooth, then move to a clean section of floss for the next gap.
Remember the back of the last tooth on each side.

If you are unsure about your technique, the Australian Dental Association suggests asking your dentist to show you.

How to use a water flosser

The Australian Dental Association suggests starting with the back teeth and working forwards, keeping the tip parallel to your teeth without pressing it against them. Guide the stream along the gumline and between the teeth, pausing for about two seconds at each tooth, inside and outside.

How often, and before or after brushing?

Once a day is the standard advice from the NHS, the Australian Dental Association, healthdirect Australia and the American Dental Association. The Australian Dental Association says a dentist may suggest cleaning more often if you have severe gum disease.

On timing, advice differs slightly:

The NHS, healthdirect Australia and the Australian Dental Association say it is best to clean between your teeth before brushing. The Oral Health Foundation adds that this lets fluoride toothpaste reach between the teeth more effectively.
The American Dental Association says it does not matter when you do it, as long as you do it thoroughly and make it a daily habit.

Cleaning before brushing follows most of this advice, but as the American Dental Association puts it, making it a daily habit is the most important thing.

Why do my gums bleed when I start?

Bleeding is common when you first start. The Australian Dental Association explains that plaque left between the teeth inflames the gums, and inflamed gums may bleed when you clean them. It says bleeding does not mean you should stop; it may mean you need to clean more often. The Oral Health Foundation says mild bleeding is common at first and usually improves with regular cleaning.

Bleeding that carries on is different. The NHS lists gums that bleed when you brush, floss or eat hard foods as a symptom of gum disease, and advises seeing a dentist. The Australian Dental Association points out that healthy gums do not bleed.

What about children?

The American Dental Association and healthdirect Australia both say to start cleaning between a child's teeth as soon as they have two teeth that touch. At first an adult will need to do it. The American Dental Association says children usually take over at around 10 or 11; healthdirect says that by about 9, a child should be able to brush and floss their own teeth. The Australian Dental Association notes that flossettes can make it easier for parents to floss a child's teeth.

What not to use

The NHS advises against wooden toothpicks, as they may damage your gums and lead to infection; the Australian Dental Association adds that they can splinter and get stuck in the gums. The American Dental Association warns that improvised tools such as fingernails or safety pins can be harmful.

When to see a dentist

Your gums keep bleeding even though you now clean between your teeth regularly.
Your gums are red, swollen or sore, or you have bad breath that does not go away.
Cleaning between your teeth is painful, or you are not sure which size or tool to use.
You have braces, a bridge or implants and want advice on cleaning around them.

Get help urgently

The NHS advises asking for an urgent dentist appointment if you have gum problems along with:

very sore and swollen gums
teeth becoming loose or falling out
ulcers or red patches in your mouth
a lump in your mouth or on your lip

Frequently asked questions

Is a water flosser as good as floss or interdental brushes?

It may help, but the evidence is limited. The 2019 Cochrane review found water flossers may reduce gum inflammation in the short term, with no evidence of a longer-term effect. The Oral Health Foundation recommends using one alongside, not instead of, brushes or floss, because water alone cannot always remove plaque.

Should I stop if my gums bleed?

No. The Australian Dental Association says bleeding does not mean you should stop, and the Oral Health Foundation says mild bleeding usually improves with regular cleaning. If it continues, see a dentist to check for gum disease.

Can I reuse an interdental brush?

Yes. The Australian Dental Association says interdental brushes can be used several times. Rinse it after each use and replace it when the bristles look worn or the wire is bent or twisted.

Sources

Home use of devices for cleaning between the teeth (in addition to toothbrushing) to prevent and control gum diseases and tooth decay, Cochrane, accessed September 2026
How to keep your teeth clean, NHS, accessed September 2026
Gum disease, NHS, accessed September 2026
Cleaning between your teeth, Oral Health Foundation, accessed September 2026
Water flossers, Oral Health Foundation, accessed September 2026
Flossing, Australian Dental Association, accessed September 2026
Dental care and teeth cleaning, healthdirect Australia, accessed September 2026
Looking after your baby or child's teeth, healthdirect Australia, accessed September 2026
Flossing, American Dental Association (MouthHealthy), accessed September 2026

This article is general information about oral health. It is not a diagnosis or a substitute for advice from a dentist or doctor who knows your situation. If you have pain, swelling, bleeding that does not settle, or a problem that is getting worse, see a dental professional. In an emergency, contact your local emergency service.