If past studies are anything to go by, most of us don't floss our teeth properly. For some people the difficulties might arise from sensory issues. Poor technique can also consistently cause bleeding gums, which can be fairly off-putting as well.

Flossing incorrectly can even damage our gums – completely contrary to the outcome we're trying to achieve with flossing: better oral health.

"Sometimes we see patients traumatize the gumline with improper flossing technique, which can create clefts by cutting the gum and can lead to gum recession," warns Tufts University periodontologist Irina Dragan.

Led by periodontologist David Basali from Tufts University, Dragan and several colleagues put flossing to the test to find the way to reduce gum bleeding – a sign of inflammation.

The purpose of flossing is to help disrupt the biofilm cities oral microbes create to protect themselves. Like so many surfaces inside (and outside) of our bodies, our mouths contain both good and bad bacteria, which secure themselves on our teeth for easy access to our blood stream.

Our body's response to this invasion can lead to problematic inflammation elsewhere, including in our hearts and brains, and has even been associated with diseases like cancer and diabetes.

micrograph of different types of bacteria around a small bit of central tissue highlighted in deferent colors
Example of a mouth microbe metropolis around dead tongue cells. (Steven Wilbert/Gary Borisy/The Forsyth Institute)

The researchers provided a group of volunteers in a randomized and single blinded clinical trial with a clear set of flossing instructions, while allowing a control group to do their usual thing.

The 36 participants who all had early signs of dental disease were assessed four times over the trial period of eight weeks. Over this time 88 percent of the trial group mastered the flossing technique and they experienced a 70 percent reduction in gum bleeding whereas the control group only saw a 30 percent reduction.

It is normal for gums to bleed when returning to flossing after some time, but this should improve gradually when flossing is done correctly, as the trial group demonstrated.

The test group was prescribed an adapted horizontal vertical flossing technique (or AHVFT), as follows:

  1. Cut off approximately 32 cm (18 inches) of floss. With palms facing each other, wind each end around the ring finger (fourth finger) of each hand. There should still be about 12 cm (6 inches) of floss between both hands.
  2. Fold hands towards the suspended floss, so palms now face down and pick up the floss between thumb and index finger in each hand.
  3. Gently place the floss between two teeth, using the thumb/index finger to control the floss and avoid cutting into the gum. Push the floss up against the side of one tooth then move it back and forth in a sawing motion while also applying upward and downward pressure, "as if one were drying their back with a towel."

Repeat this technique on all your teeth.

The study participants were dental students and assistants, which probably explains why there was such a strong take-up of the technique in the trial group, the team note.

"This is the first study of which we are aware to prove that a person using floss with a specific technique will have less gum infection than a person who just does what they normally do," says periodontologist Paul Levi.

As someone who's always had a complicated relationship with flossing, I for one am keen to give this a shot!

This research was published in the Journal of Dental Hygiene.