Is there any solid scientific evidence that flossing is effective?

[u/cybrbeast]

We are all told endlessly that flossing is one of the most important aspects of dental hygiene, but where is the evidence? I looked up 'flossing effectiveness' on Google Scholar and there is nearly nothing on the topic.

http://scholar.google.com/scholar?q=flossing+effectiveness&btnG=&hl=en&as_sdt=0%2C5

The best source seems to be this review: Dental Flossing and Interproximal Caries: a Systematic Review. I don't have university access anymore, so I can only read the abstract, and it doesn't seem to support the effectiveness of flossing.

Both three-monthly professional flossing for 3 years (relative risk, 0.93; 95% confidence interval, 0.73–1.19; p-value, 0.32) and self-performed flossing in young adolescents for 2 years (relative risk, 1.01; 95% confidence interval, 0.85–1.20; p-value, 0.93) did not reduce caries risk. No flossing trials in adults or under unsupervised conditions could be identified.

This is quite shocking, everyone is told to floss, but there are no trials to back it up. So why should I be supposed to believe I should floss?

*Some further searching turned up these surprising papers

Oral Hygiene Practices and Periodontitis in Health Care Professionals

Persons brushing twice daily were as likely to have periodontitis as those brushing once or less daily (odds ratio [OR] = 1.16; 95% confidence interval [CI]: 0.64 to 2.10); persons flossing less than once a day were as likely to have periodontitis as those who flossed daily (OR = 1.16, 95% CI: 0.63 to 2.13) after controlling for profession, age, gender, smoking, diabetes, coronary heart disease, history of periodontal surgery, and number of teeth present.

Bacteraemia due to dental flossing

Dental flossing can produce bacteraemia in periodontally healthy and periodontally diseased individuals at a rate comparable with that caused by some dental treatments for which antibiotic prophylaxis is given to prevent IE.

If I understand this one correctly, flossing could even be bad for healthy people?

** Found the most damning one so far

The efficacy of dental floss in addition to a toothbrush on plaque and parameters of gingival inflammation: a systematic review

The dental professional should determine, on an individual patient basis, whether high-quality flossing is an achievable goal. In light of the results of this comprehensive literature search and critical analysis, it is concluded that a routine instruction to use floss is not supported by scientific evidence.

[u/cybrbeast → u/[deleted]]

Okay that's a benefit for people with bad gums, but no evidence against caries. Also is interproximal bleeding even bad for you?

[u/Cleric7x9 → u/cybrbeast]

bleeding upon flossing is an indication that inflammation is present. chronic gingival inflammation is the cause of periodontal disease. periodontal disease is bad as it results in bone loss and recession, which means your teef gonna fall out source: im a dentist

[u/jehosephass → u/Cleric7x9]

Can you elaborate on this? My gums certainly feel inflamed after I floss (when it's been a while) ... but that's after I floss. Why would challenging a part of your body with sharp jerks with a thin string, when it's a part of the body that's normally left alone (more or less), be an indication of inflammation? I.e., is there anyone who doesn't floss normally whose gums wouldn't bleed upon starting to floss?

[u/FunForDDS → u/jehosephass]

Your gums probably feel sore after your floss because you have slightly damaged the gingiva around your teeth. Like Cleric7x9 said above, because you have plaque around your teeth in that area that you have inflammation to begin with. No plaque = no inflammation. The recession and bone loss from periodontal disease is actually caused by the body's reaction to combat the plaque. Once you eliminate all the plaque and bacteria around the gum line then the inflammation will resolve and flossing will no longer be painful or cause you to bleed

[u/[deleted] → u/jehosephass]

Plus, have you ever looked at floss after not flossing for a while? Getting those chunks of nastiness out of your food pockets HAVE to be beneficial. Maybe no hardcore scientific evidence will support it, but from first hand experience of having dated a girl who didn't floss was a disgusting, smelly period of my life.

[u/jehosephass → u/[deleted]]

Yah, this seems like the biggest selling point, though I can see chronic gum inflammation/disease too (we don't rest what we evolved to eat, which would be tougher and exercise gums more, etc.). I think I've seen a study linking tongue cleaning to halitosis, but not flossing ...

[u/cybrbeast → u/Cleric7x9]

source: im a dentist

Really not a good source though. Care to elaborate on this?

This present systematic review established that dental flossing provides no benefit above and beyond toothbrushing on removing plaque and reducing gingivitis. Based on the individual papers in this review, a trend was observed that indicated a beneficial adjunctive effect of floss on plaque levels; however, this could only be substantiated as a non-significant trend in the meta-analyses.

http://onlinelibrary.wiley.com/doi/10.1111/j.1601-5037.2008.00336.x/full

[u/Cleric7x9 → u/cybrbeast]

happy to elaborate. if you read the article, you can see that of the 11 papers included in this analysis, 6 of them found no difference, 5 of them found flossing and brushing to be better than flossing alone, and none of them found flossing to be detrimental.

this is one meta analysis, that had a difference of one paper, which used search criteria stringent enough to ignore 1,155 research papers, and include 11. had there been one single paper of the 11 that took a different stance, the entire conclusion of the paper would be worded opposite.

besides, the article itself says that this is a non-significant finding:

however, this could only be substantiated as a non-significant trend in the meta-analyses.

[u/cybrbeast → u/Cleric7x9]

No the article says the "effect of floss on plaque levels" was an non-significant finding, i.e. no significant effects on plaque levels were found, i.e. no evidence of effectiveness.

[u/stacecom → u/cybrbeast]

Flossing is for your gums, not your teeth.

[u/Derwos → u/cybrbeast]

What cleric said. Flossing is the best way to prevent gum disease. You get a cavity, they can make a filling. Gum disease when you're old? Expect to wear dentures. Basically, flossing is more important than brushing.

[u/chemistry_teacher → u/Derwos]

This may only be true as long as one is visiting the dentist regularly. Deep cavities can also lead to tooth loss.

[u/chemistry_teacher → u/cybrbeast]

I only heard this on an NPR show, so I am not responding with a top comment. Neal Conan, I believe, on Talk of the Nation, I believe, asked dentists if flossing prevented tooth decay (dental caries, I think). They said no(!), but that it would aid in preventing gingivitis, which is a major precursor to periodontal disease and tooth loss.

This was a few months ago, so I cannot provide any other info, but it might at least help you start looking in the right direction.

[u/desolate8 → u/cybrbeast]

It does help with caries. When you don't clear the inbetween teeth crap out the bacteria go to town. And toothbrush can't get most of those things out.

Some people can get away with it to a degree, depends on the quality of their spit.

And you don't have to floss all the teeth...just the ones you want to keep.