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Interdental Cleaning – Floss vs Interdental Brushes

Medically Reviewed By: Dr. Gemma Wheeler

(GDC Number: 259369)

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In 2016, the recommendation for daily flossing was taken out of the dietary guidelines that the federal government offered.

The removal of this was triggered by the work of the Associated Press (AP) which resulted in the government acknowledging that the effectiveness of flossing had never been researched, as required.

Such acknowledgements confirms the findings of reviews such as that by Cochrane that concluded:

“There is some evidence from twelve studies that flossing in addition to toothbrushing reduces gingivitis compared to toothbrushing alone. There is weak, very unreliable evidence from 10 studies that flossing plus toothbrushing may be associated with a small reduction in plaque at 1 and 3 months. No studies reported the effectiveness of flossing plus toothbrushing for preventing dental caries.”

Local, national and international media have since jumped on this story, but the American Dental Association (ADA) state:

” The bottom line for dentists and patients is that a lack of strong evidence doesn’t equate to a lack of effectiveness.”

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The American Academy of Periodontology (AAP) added:

“Much of the current evidence does not utilize a large sample size or examine gum health over a significant amount of time. Additionally, many of the existing studies do not measure true markers of periodontal health such as inflammation or clinical attachment loss. In the absence of quality research, patients should continue to include flossing as a part of their daily oral hygiene habit.”

You might feel a little cheated and perhaps disappointed to find out that after so many years of being advised to do something the reality is that there is weak evidence to justify the need for it.

It may well be the dental industry as a whole who have benefited most from sales of flossing products over this time, it is important to remember that dentists are trying encourage better oral care and reduce the knock on effects of poor routines.

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Whilst evidence is incredibly helpful, there is a degree of common sense that comes into the equation here.  Surely cleaning the gaps in between the teeth has to be beneficial?

When you brush your teeth with a manual or electric toothbrush, you are only cleaning 3 of the 5 sides of your teeth. Whilst the bristles of the toothbrush do reach into the gaps between teeth, their reach and cleaning effectiveness is limited.

In fact, by brushing your teeth alone you are only cleaning 60% of the tooth surface. 40% goes uncleaned unless you clean those interdental spaces.

I think that the ADA’s comments summarise my feelings on the matter very well.

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So with this said, if it is still important to clean those interdental spaces (the gaps between the teeth).

In a separate article I take a detailed look at the best flossing tools available for cleaning in between the teeth.

It is dental floss and interdental brushes that are the most widely used but naturally the question often asked, is which is better?

The short answer to this question is really it depends on who you ask.

Dr. Susan Karabin, President of the AAP endorses both products, whilst Dr Joseph Haddad believes floss is best, he acknowledges that either is beneficial if the patient uses it to clean away the plaque that builds up between the teeth.

The reality is that there is a place for both.

Let’s not hide from the fact that as a nation, it is somewhat concerning that 47.2% of the population have periodontal disease (Centers for Disease Control and Prevention), a condition that is strongly influenced by the lack of flossing.

Floss works best in the tightest gaps, where brushes struggle, whilst a brush is more effective in the large spaces, able to make more surface contact than floss, with less effort.

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Interdental brushes have really grown in popularity as a result of the ease with which that add to flossing.  The shape, design and functionality is just a bit more appealing to use on an everyday basis than string floss for most people.

So, if interdental brushes are the new recommendation, what are the pros and cons and how do they compare to floss?

Flossing: A Quick Guide To Getting Started

Interdental Brushes – Pros

  • More effective at cleaning in between the teeth – the bristles move and compress into different sized and shaped gaps than floss.
    • Removes more bacteria than flossing and toothbrushing or toothbrushing alone.
    • Resolves the symptoms of gingivitis (gum disease)
  • Different sized brushes for different sized gaps in the teeth, not a one size fits all approach like floss.
  • Easier to handle and clean in between – Just a back and forth motion needed and there are handles (short and long) on interdental brushes, making it better for all, particularly those with limited dexterity.
  • Can bend the tips – Flexible brush heads make it simpler to get into gaps.
  • Only option for braces – Floss simply does not suit those who wear fixed braces, brushes clean deeper and around fittings.
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Interdental Brushes – Cons

  • More expensive than floss – Require different sizes for different gaps.
  • Can cut gums – If used aggressively the wire construction can cut or aggravate gums.
  • Bacteria build up – Whilst they can be rinsed off and reused for about a week bacteria can build up on the bristles and then be essentially planted back in the mouth because the brush is not sterile.
  • Time consuming – Getting in between all those gaps takes a lot of time.

You can learn more about interdental brushes by reading our article on the best interdental brushes.

Flossing Pros

  • Cheap – Reels of floss can be picked up for very little money.
  • Fits in very small gaps – Ideally suited for gaps so tight that an interdental brush will not fit into.
  • Hygienic – Disposing of the floss after use ensures the bacteria is removed.
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Flossing Cons

  • No proven results – The Associated Press discovered very weak evidence that it is beneficial.
  • Difficult – Getting the floss in between the teeth and cleaning effectively can be very awkward, particularly for rear teeth and those with limited dexterity.
  • Painful – Can cut into the gums and be unpleasant to use.
  • Time consuming – Getting in between all those gaps takes a lot of time.
  • Not suitable for fixed braces – Unable to manoeuvre or effectively clean when braces are worn.

So is it time to bin the floss?


The media might suggest so, but when you really understand it, the answer is not that clear cut.

Arguments will roll on forever about which is better, floss or interdental brushes and whether any of it is needed at all.

Both are just different types of tools and data and evidence can always be swung one way or another.

The lack of large, long term trials is disappointing considering the expectations and standards we have today.

But, specialist know that not cleaning in between the teeth can lead to a buildup of plaque and bacteria between them.  They also know that there are links between interdental cleaning and oral health, most notably periodontal disease.

Therefore taking clear preventative steps is important and any tool (assuming it is safe) that helps reduces gum disease and other oral health conditions has to be beneficial.

Where once floss was your go to option, an interdental brush is now and option.

Ultimately, everyone’s needs are different and dentists are best placed to recommend the best approach for you.

About Jon Love

Jon is a leading voice on electric toothbrushes and has been quoted by mainstream media publications for his opinions and expertise.

Having handled & tested hundreds of products there really is very little he does not know about them.

Passionate about business and helping others, Jon has been involved in various online enterprises since the early 2000s.

After spending 12 years in consumer technology, it was in 2014 that he focused his attention on dental health, having experienced first-hand the challenge of choosing a new toothbrush.

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