Recently I had to go through a lot of ultrasound teeth cleaning because my gums suffered inflammations in the past. I am doing the dental cleaning every 3 to 4 months and every time the dentist says that the gum is getting better and better because I am flossing thoroughly. Before the inflammation, I never flossed so this is kind of a novel procedure for me.

So I empirically assumed that flossing is really the thing that helps to heal, as also acknowledged by the dentist.

The thing is... there are actually no studies to prove this statement. I have looked for articles and I found for instance this and this and this. I understand from the articles that there is not sufficient proof to endorse the procedure. Despite this, the dentists still recommend flossing.

From one of the articles:

The evidence for flossing is “weak, very unreliable,” of “very low” quality, and carries “a moderate to large potential for bias.”

What should one understand from this? Is there someone here that works in this field or did some research on this issue?

The reason why I ask this is that I want to eliminate using the floss and replace it with WaterPik, which I find more comfortable, fast and less abrasive. But I have also seen articles in which they write that floss is better than WaterPik. So then I come back to the same issue...

I would also like to know if the dental ultrasound cleaning is actually the one healing me or is the flossing? Can anyone help me with this?

  • No studies that show it works is not the same as studies that show it doesn't work.
    – alex
    Commented May 24, 2017 at 10:49

1 Answer 1


Is dental floss really effective? The evidence shows that we don't know. Here the main issue is the lack of good evidence.

How we find how effective is? Simple: we took a group of people with similar age, similar dental status, and divide randomly to one group who will use floss and other who don't. Then, we wait for one, two or five years and compare caries and periodontal disease.

This is the theory.

In practice, there is no experimental trials like this. All that we have are observational studies tracking the oral health of people who floss and people who don't. Hence, sometimes we see that people who floss have better oral health that people who dont and sometimes the contrary. For example, if we ask @jess, we will record the he floss AND he have periodontal issues.

The main issue with observational evidence is that, maybe, for some reason, the people who floss is essentially different from the people who don't. For example maybe the people who floss eat more vegetables and that is the reason why they have better oral health. Or, on the contrary, maybe the people who floss have more periodontal problems, and in such case we will find the opposite, that floss is correlated with periodontal disease.

Is hard to extract conclusions from observational evidence and that is the conclusion of most systematic reviews: we don't have evidence that indicate that floss is effective. But also we don't have evidence showing that floss is ineffective.

Hence, is wise to ask your dentist for your personal condition, taking in consideration all your particular characteristics and follow her/his advice.

TL;dr: The scientific research does not show that flossing is effective against tooth decay or gum disease. But it doesn’t show it’s not.

More info:

Sambunjak et al. Flossing for the management of periodontal diseases and dental caries in adults. Cochrane Database of Systematic Reviews 2011, Issue 12. Art. No.: CD008829. DOI: 10.1002/14651858.CD008829.pub2

Hujoel et al. Dental flossing and interproximal caries: a systematic review. J Dent Res. 2006 Apr;85(4):298-305.

  • This is a great answer. It makes sense! Thank you so much!
    – Physther
    Commented Jun 2, 2017 at 9:24

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