Surveys consistently show that most people either do not floss regularly, or floss in a way that is minimally effective. Given that roughly 35% of each tooth surface is between the teeth — completely unreachable by brushing — this gap in most people's routines has real consequences for both cavities and gum health.
Why Flossing Matters
Tooth decay and gum disease both begin where plaque accumulates undisturbed. Brushing addresses the front, back, and chewing surfaces of each tooth, but the tight spaces between teeth are effectively brushing-dead zones. Interdental spaces are where cavities most commonly start (you can see them on bitewing X-rays) and where the early stages of gum disease most reliably develop.
Daily flossing disrupts the bacterial biofilm in these spaces before it can cause damage. The disruption does not require perfect removal — even partial plaque disruption significantly reduces gum disease risk.
The Correct Technique
- Take about 18 inches of floss and wind most of it around your middle fingers, leaving a two-inch working section.
- Hold the floss taut between your thumbs and forefingers and guide it gently between two teeth using a zigzag motion — do not snap it down into the gum.
- Curve the floss into a "C" shape around one tooth and slide it gently beneath the gum line. Hold it against the tooth surface and move it up and down several times.
- Then curve the floss around the adjacent tooth and repeat on that surface.
- Unwind a fresh section of floss as you move to each new pair of teeth.
The key mistake most people make is simply passing the floss between the teeth and pulling straight out. This removes some food debris but does almost nothing for the bacterial plaque adhering to the tooth surfaces just below the gum line. The C-shape scraping motion against each tooth surface is the part that actually cleans.
When to Floss
Floss before you brush — not after. When you floss first, you loosen plaque and debris from between the teeth, and then brushing with fluoride toothpaste can remove it and deliver fluoride to the newly cleaned interdental surfaces. Flossing after brushing means brushing's benefits precede the interdental cleaning rather than following it.
Once per day is sufficient — the bacterial biofilm that causes gum disease takes approximately 24 hours to mature to a level that triggers inflammation. A daily disruption keeps it below that threshold.
Floss Alternatives That Actually Work
Floss picks (flossers): Pre-threaded plastic picks. Easier to maneuver, particularly for back teeth. The Y-shape makes the C-curve technique more difficult but still achievable. Good option if you find traditional floss awkward.
Interdental brushes (proxy brushes): Tiny bottle-brush type tools that fit between teeth. More effective than floss for people with spaces between teeth, implants, bridges, and fixed orthodontic retainers. Available in multiple sizes — ask your hygienist which size fits your gaps.
Water flossers (Waterpik): Use a pressurised stream of water to flush between teeth and below the gum line. Excellent for braces, bridges, implants, and people with limited dexterity. Evidence shows water flossers reduce gum bleeding and improve gum health, though some research suggests they are slightly less effective than string floss at plaque removal in healthy mouths. Best used as a supplement to, not a replacement for, mechanical interdental cleaning.
What About Bleeding Gums?
If your gums bleed when you floss, this is almost always a sign of gingivitis — gum inflammation from plaque buildup in the interdental spaces. The solution is to floss more, not less. Most people who start flossing consistently find that bleeding stops within one to two weeks as the gum inflammation resolves. If bleeding is heavy, persists beyond two weeks of consistent flossing, or occurs spontaneously, see your dentist.