Good flossing is slow and gentle. Most people who find it painful, or who see little benefit, are pulling the floss straight down through the contact and back out again, which cleans almost nothing and can cut the gum. The aim is to wrap the floss against the side of each tooth and wipe the plaque off that surface, then do the same to the tooth next door.
The Australian Dental Association recommends cleaning between your teeth at least once a day. A toothbrush cleans the outer, inner and biting surfaces well, but the bristles do not get far into the narrow space where two teeth meet, and that space is where gum inflammation and decay between the teeth often begin.
Floss reaches the surfaces your brush skips
Plaque is a sticky film of bacteria that forms on teeth every day. Where it sits undisturbed between the teeth and along the gumline, the gum reacts with redness, swelling and bleeding (gingivitis). Removing it regularly lets the gum settle. If your gums already bleed when you clean, our article on bleeding gums when brushing covers the common causes.
The research on flossing is less dramatic than the advertising. A 2019 Cochrane review led by Worthington pooled 35 trials and found that adding floss or interdental brushes to toothbrushing may reduce gingivitis or plaque compared with brushing alone. The evidence was rated low to very low certainty and most trials were short, so the size of the benefit is uncertain. Daily interdental cleaning is still what Australian guidance recommends, because plaque control between the teeth is hard to achieve any other way.
The technique, one gap at a time
Break off about 30 to 45 centimetres of floss. Wind most of it around the middle finger of one hand and a little around the middle finger of the other, so you can take up used floss as you go. Pinch a short working length, a few centimetres, between your thumbs and index fingers.
- Ease the floss through the tight contact point with a gentle sawing motion. Do not snap it down onto the gum.
- Curve the floss around one tooth so it hugs the side in a C shape, then slide it just under the gumline until you feel light resistance.
- Rub it up and down along that side a few times. Up and down, not back and forth across the gum.
- Without lifting out, curve it around the neighbouring tooth and repeat.
- Lift the floss out, wind on a clean section, and move to the next gap. Include the back surface of the last tooth in each row.
Going round the mouth in the same order each time, for example upper right to upper left then lower left to lower right, makes it less likely you will miss a space. The first week can feel awkward. Most people speed up once the movement becomes familiar.
Mistakes that make flossing hurt
Snapping the floss through the contact is the most common one. It drives the floss into the gum between the teeth, which stings and can leave a small cut. Sawing back and forth at the gumline does the same. Using one short piece for the whole mouth is another: once the floss is frayed or loaded with plaque it shreds and simply moves debris around.
Some bleeding in the first few days is common when the gums are inflamed, and it is not a reason to stop. healthdirect advises that if your gums are still bleeding after 3 to 4 days of good brushing and flossing, you should see a dentist or oral health therapist.
Floss is not the only tool
For many adults, small interdental brushes are easier to use and fit gaps that floss slides through without touching the tooth. In the same Cochrane review, low-certainty evidence suggested interdental brushes may reduce gingivitis more than floss. Floss still suits tight contacts where a brush will not fit.
| Tool | Suits | Things to know |
|---|---|---|
| String floss | Tight contacts between healthy teeth | Inexpensive; the C shape takes practice |
| Floss picks | People who struggle to reach the back teeth | Easy to hold, but harder to wrap around the tooth |
| Interdental brushes | Wider gaps, braces, bridges, implants | Need the right size for each gap |
| Water flosser | Braces, limited hand movement | A useful extra; evidence for lasting benefit is limited |
Our guides to using an interdental brush and using a water flosser walk through each one.
Before brushing, at a time you will keep
A small crossover trial in 25 dental students (Mazhari and colleagues, Journal of Periodontology, 2018) found that flossing first and then brushing removed more plaque between the teeth and left more fluoride there than brushing first. It was a short study, so treat it as a sensible tip rather than a rule. The bigger factor is doing it every day. Many people find the evening, as part of the bedtime routine, is the slot that sticks.
Common questions
When should children start?
Once two teeth sit side by side and touch, plaque can collect between them. Young children do not have the hand control to floss, so a parent usually does it for them, and a dentist or oral health therapist can show you how.
Is a water flosser enough on its own?
For most people it works best as an addition rather than a replacement. In the Cochrane review, evidence that water flossers reduce gum inflammation beyond brushing alone was limited and inconsistent.
Should flossing ever be uncomfortable?
Mild tenderness while the gums settle can happen. Sharp pain, a gap that always traps food, or floss that keeps shredding in the same spot can point to decay, a rough filling or a gum problem, and is worth having checked.
If you would like your technique checked, a hygiene visit is a good time to do it, and our article on what a dental clean costs explains what is involved. Daily interdental cleaning also supports treatment for gum disease. You can see our current offers or book with the Lumi Dental team in Melrose Park.
