Should you floss twice a day?

How often should you floss?

The ADA recommends brushing twice a day and cleaning between your teeth once a day with floss or another interdental cleaner. It says the timing is flexible, and morning, midday or bedtime all work if they fit your routine. Cleveland Clinic likewise says to floss daily and to brush twice a day for two minutes, and notes that fewer than 1 in 3 adults floss every day.

The question people usually ask, whether twice a day is better than once, is not answered by the sources we read. They recommend cleaning between your teeth daily and do not give a benefit for doing it twice.

Before or after brushing?

The ADA says flossing before or after brushing is acceptable, as long as the cleaning is thorough. The most important thing is that the floss reaches the plaque between teeth where a brush cannot, and that you do it consistently.

Can you floss too much?

The sources do not set a limit on how often, but they do describe how to avoid harming your gums. Cleveland Clinic lists pressing too hard, using a worn or hard-bristled brush and flossing too far into the gums as causes of bleeding, and says in its technique steps not to push the floss too far into the gums. Use a clean section of floss for each set of teeth, and slide the floss gently up and down along each tooth's curve.

How to floss

Cleveland Clinic's steps: start with about 24 inches of floss, wrap it around both middle fingers leaving about 2 inches to work with, hold it taut with your thumbs and index fingers, gently guide it between two teeth in an up-and-down motion following the curve of each tooth, do not push too far into the gums, and use a clean section for each set of teeth. The ADA says waxed and unwaxed floss work equally well, though rare contact hypersensitivity to waxed floss has been reported, and that you should not rinse and reuse floss or other interdental cleaners but discard them after use.

Floss versus water flossers and interdental brushes

The ADA says a 2019 Cochrane review found that floss or interdental brushes used with toothbrushing may reduce gingivitis or plaque more than brushing alone, and that interdental brushes may outperform floss. It describes the evidence as low to very low certainty, and says evidence for oral irrigators (water flossers) and tooth-cleaning sticks was limited and inconsistent. It says the right choice depends on the person: floss may suit tight spaces, while interdental brushes may suit periodontitis or more open spaces.

So the sources do not say a water flosser can replace flossing, and they do not say it cannot. Ask your dentist which tool fits your teeth.

Why your gums may bleed when you floss

Cleveland Clinic says bleeding usually comes from plaque, tartar and bacteria along the gumline, and that not flossing daily is typically the main cause of bleeding gums, which can lead to gingivitis. Other causes it lists include technique, hormonal changes and some medical issues. ADA MouthHealthy says bleeding is common when you start flossing because your gums are adjusting, and that it usually goes away on its own in about a week. Cleveland Clinic says that if you floss daily, bleeding should stop within a few weeks as your gums get healthier.

Bleeding that does not settle needs a dental visit. Both sources say healthy gums should not routinely bleed.

Why teeth might hurt after flossing, and floss that smells

The sources we read do not directly address teeth hurting after flossing or why floss can smell. Pain or tenderness after flossing can be a sign of inflamed gums or of flossing too forcefully, so slow down and be gentle, and mention it to your dentist if it continues. A smell on floss can reflect plaque and bacteria between the teeth, but we did not find a source that says so, and persistent bad breath is a reason to be checked.

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