Flossing Has At Least Been Good For Floss Manufacturers. And Now, About Those Fluoride Studies...
We trusted our doctors to practice evidence-based dietary medicine -- doctors who advised us based on the bad science of Ancel Keys to eat a high-carb, low-fat diet. Diabetes and obesity skyrocketed -- though now, more and more people are vastly reducing their weight and staying slim and even knocking out symptoms of diabetes by eating low-carb, high-fat diets.
Now, however, we find that it's the American Dental Association (or rather the "Sell Tooth Stuff To People" Association) and dentists who have been pushing unproven bullshit. Jeff Donn writes for the AP, "Medical benefits of dental floss unproven":
HOLMDEL, N.J. (AP) -- It's one of the most universal recommendations in all of public health: Floss daily to prevent gum disease and cavities.Except there's little proof that flossing works.
Still, the federal government, dental organizations and manufacturers of floss have pushed the practice for decades. Dentists provide samples to their patients; the American Dental Association insists on its website that, "Flossing is an essential part of taking care of your teeth and gums."
The federal government has recommended flossing since 1979, first in a surgeon general's report and later in the Dietary Guidelines for Americans issued every five years. The guidelines must be based on scientific evidence, under the law.
Oopsy.
Last year, the Associated Press asked the departments of Health and Human Services and Agriculture for their evidence, and followed up with written requests under the Freedom of Information Act.When the federal government issued its latest dietary guidelines this year, the flossing recommendation had been removed, without notice. In a letter to the AP, the government acknowledged the effectiveness of flossing had never been researched, as required.
The AP looked at the most rigorous research conducted over the past decade, focusing on 25 studies that generally compared the use of a toothbrush with the combination of toothbrushes and floss. The findings? The evidence for flossing is "weak, very unreliable," of "very low" quality, and carries "a moderate to large potential for bias."
"The majority of available studies fail to demonstrate that flossing is generally effective in plaque removal," said one review conducted last year. Another 2015 review cites "inconsistent/weak evidence" for flossing and a "lack of efficacy."
One study review in 2011 did credit floss with a slight reduction in gum inflammation -- which can sometimes develop over time into full-fledged gum disease. However, the reviewers ranked the evidence as "very unreliable." A commentary in a dental magazine stated that any benefit would be so minute it might not be noticed by users.
It seems intuitively important to get stuff out from between your teeth.
From a dentist, Grant Ritchey, at Science Based Medicine:
The first systematic review I will cover is "Dental flossing and interproximal caries: a systematic review" by Hujoel, et. al. In this systematic review, the investigators assessed the effect of flossing on interproximal (between the teeth) caries (tooth decay) risk. Toothbrushing doesn't reach between the teeth, therefore flossing is the logical solution to preventing cavities there. The authors identified six trials involving 808 subjects aged 4 to 13. In one of the reviewed studies, children were professionally flossed every school day for 1.7 years, which resulted in a 40% reduction of caries risk. Professional flossings every three months for three years as well as self-performed flossing for two years did not statistically alter caries risk. Again, they looked only at tooth decay reduction, not gum disease. The take home message from this review is that:Flossing when done by professionals five days per week works! That means if everything goes just right, if you know what you are doing (e.g., you are a dental hygienist or a dentist), you have good visualization of the teeth from outside the mouth, you are motivated and do the job regularly, you can in fact reduce caries. This is the definition of efficacy.
1. If you don't do it five days per week but just occasionally (even if you are good at it) there is no benefit in terms of lessening your chances of getting a cavity.2. If you ask people (adolescents) to do it themselves, they can not achieve a good result. Why? They probably can't technically do it right, don't do it often enough, or some other unknown reason. This is the definition of effectiveness.
3. So the conclusion for caries prevention is that flossing has some efficacy but not good effectiveness when left to patients to be the flosser.
OK, now that you're all bummed out because you've been misled by your wonderful dentist and hygienist all these many years, let's see if flossing confers any benefit in the prevention of periodontal (gum) disease over and above flossing alone. There has to be SOMETHING to this flossing thing, right?
...To summarize, flossing might make your gums less puffy, and likely makes your mouth feel better without those hunks of shredded chicken stuck in that annoying space between your molars, but it really doesn't do much in terms of any sort of disease prevention.
As a dentist, these reports are distressing to me, as our brushing and flossing screeds have always been the cornerstone of our oral health education, not only in our practices, but in public health and dental outreach programs as well. As a health care practitioner with a science-based outlook, however, I must accept the current evidence and realize that when I recommend brushing and flossing, it is for reasons other than caries and periodontal disease prevention. It's tough to change a fundamental worldview like this, but change it I must.
That being said, I am still going to recommend that my patients brush and floss, and I'm pretty sure I will continue to brush and floss myself. Why? For one, it's in our DNA. Just as salmon must return to their birth rivers to spawn, we dental professionals are compelled to drone on and on about brushing and flossing. We can't help it. Second, floss is cheap, and there's really no downside to doing it. Third, the reviews discussed above are statistical analyses, and despite the overall lack of proven efficacy on a population level, on an individual basis there will be people who may prevent disease by good oral hygiene practices. And finally, most people don't want their mouths to taste and smell like the bottom of a birdcage. I will, however, make a point henceforth to not tell my patients that if they brush and floss more/better they won't get as many cavities or have as many periodontal issues. Instead, I will focus on proven, science-based methods for disease prevention such as fluoride use, sealants when and where indicated, dietary counseling to reduce sugar consumption, smoking cessation to reduce periodontal disease risk, and the like.
Oh, and good evidence for fluoride? Um...not so much. This isn't to say it doesn't work. But the studies aren't good and there may be risks from fluoride toothpaste and fluoride in our water that we don't know about.
I know -- that's not what your dentist and the ADA tell you.
via @bigfatsurprise
Flossing makes my breath smell good. That's the only reason I need. Whether or not I have been doing it regularly, dentists always tell me that my "home care is excellent" and I have very little plaque, so this new information sounds about right to me.
My parents both had terrible problems with cavities. My brother and I have scarcely had any. I know that is hardly a controlled experiment, but I can't think of any significant variables other than fluoride (and, of course, our genetic dice rolls).
This also is anecdotal, but my hippie friends who use "all natural" baking soda and mint toothpaste have kids whose teeth are rotting out of their mouths. I tilt toward using fluoride unless I find out there /are/ significant health risks.
Insufficient Poison at August 2, 2016 9:05 PM
Flossing never did a damn thing for me, but regular use of oxygenating mouth rinse (including all the sucking between the teeth) really makes a difference.
Other than that, my teeth are going bad at the same rate and in the same way as my mother and her siblings.
Kevin at August 2, 2016 11:15 PM
IP, look at diet. What you eat matters a whole lot more than how well you clean up afterwards.
Amy, I thought the risks of fluoride overdose were well understood. Fluorosis is quite real. The study you linked to showed substantial benefits for children with fluoridated water supplies (26% fewer decayed teeth in adulthood). Yes, they don't show benefits for adults. Some things are much harder to change later in life.
Ben at August 3, 2016 5:07 AM
I personally floss because it makes my gums less swollen, and there's some kind of correlation between flossing and mouth care in general, and my allergies acting up.
spqr2008 at August 3, 2016 5:19 AM
I wonder if those water toothcleaners (high-pressured water) are better than flossing. Perhaps shitty research on that, too!
Amy Alkon at August 3, 2016 5:26 AM
Amy, those water toothcleaners are what I use after flossing, since it lets me target any allergy induced swelling that the flossing has not tamped down. They are amazing for my nose and throat (seriously, again anecdotal data, but a $50 one cut my number of sinus infections in half the last 2 years).
spqr2008 at August 3, 2016 5:40 AM
Amy, those water toothcleaners are what I use after flossing, since it lets me target any allergy induced swelling that the flossing has not tamped down. They are amazing for my nose and throat (seriously, again anecdotal data, but a $50 one cut my number of sinus infections in half the last 2 years).
spqr2008 at August 3, 2016 6:17 AM
Fluroide is naturally found in a lot of drinking water. Like other trace minerals it leaches out of the the ground where it is present.
it was strictly scientific observation that kids who drank water naturally higher in fluoride had much better teeth than those who did not.
On the subject of anecdotal evidence. My father was born in a town with high fluoride water, as were his older brother and sister. They all had great teeth.
His three younger siblings born in a different town with poor water did not.
Evidence seems to suggest that the mineral composition of the water that the mother drinks while she is pregnant with the children may matter as well.
Isab at August 3, 2016 7:23 AM
It doesn't look like they did research on people with existing gum inflammation/periodontal disease. But only after my dentist instructed me that I'd been doing it wrong my whole life. Perhaps if people were given instructions, it would help.
This may sound silly, buy my allergist found a way to reduce nosebleeds from nasal steroid sprays just by instructing people to point the spray a bit to the "outside, away from the middle of the nose."
Shannon at August 3, 2016 7:58 AM
I used to go to bed with gumdrops still stuck to my teeth. I don't know why, but as a child I /hated/ brushing my teeth and would pull tricks like just wetting my toothbrush and then running the faucet to make it seem like I'd done it.
I know it's still not "data."
Insufficient Poison at August 3, 2016 8:21 AM
My personal experience is flossing is good for large things stuck between my teeth and a water pick is better for bio film, sticky sugars, and such.
Also a personal anecdote, flossing often causes me to have inflamed gums. I have a mild allergy to mint. So most toothpaste causes painful sensitivity in my teeth. But mint coated floss is just enough to inflame my gums without causing pain. So whenever I got really good at flossing the dentist always told me I wasn't flossing enough.
Ben at August 3, 2016 9:17 AM
Recently I read that you shouldn't brush your teeth too soon after drinking something acidic because this scrubs away enamel you've just permeated or something. Well, I wear clear braces, and I can't put them back on unbrushed teeth or the coffee/wine or whatever gets trapped.
So no matter what I do, I'm doing something wrong.
Insufficient Poison at August 3, 2016 10:07 AM
So no matter what I do, I'm doing something wrong.
I gave up after one hygienist told me there was no such thing as too much tooth brushing ("you can't harm them with a toothbrush") and then another said it was clear "you're brushing your teeth too hard."
At this point: twice a day, more if necessary, oral rinse, and what will be will be.
Kevin at August 3, 2016 2:01 PM
https://www.youtube.com/watch?v=brU_Pp-20g0
lujlp at August 3, 2016 2:28 PM
I don't know if flossing does all the things the ADA hyped it for, but I know that if I don't floss, my gums bleed. And in no study or medical literature is bleeding gums listed as a good thing.
Conan the Grammarian at August 3, 2016 5:11 PM
I don't know if flossing does all the things the ADA hyped it for, but I know that if I don't floss, my gums bleed. And in no study or medical literature is bleeding gums listed as a good thing.
Conan the Grammarian at August 3, 2016 5:11 PM
I used to have episodes of bleeding gums. Can be caused by two other things, rather than not flossing. The first is NSAIDs and for me, the second, is bread.
If I don't take Aleve, except on an occasional basis, and I don't eat bread, my gums don't bleed.
Isab at August 4, 2016 8:40 AM
If I brush twice a day with bristles angled into the gums at 45-degree angle, for 1-2 minutes, no bleeding gums.
My (vague) understanding is that you have to "massage" them or rough them up a little to keep them healthy. If someone is brushing too hastily or not pushing into the gums with the brush, then flossing might be more necessary.
I still floss because it's clear to me that leaving food between my teeth isn't going to lead to awesome breath. A toothbrush can't get it all out, every time.
Insufficient Poison at August 4, 2016 10:37 AM
I've seen a study somewhere that said that people who floss regularly have a lower incidence of congestive heart disease. The conjecture was that reduces a vector for bacteria to enter the bloodstream. The study could well be full of confounding factors (e.g. people who floss are more likely to take care of their health generally); I haven't looked at it in detail.
I floss because I remember when I was a teenager and I had the old-fashioned band braces that made flossing all but impossible. My mouth always felt disgusting and it seemed like I always had bad breath no matter what I did. I also had a ton of cavities and enamel wear while I had those on. Caveat: I was one of those early-1960s kids who had their permanent teeth stained by tetracycline, and I've read some things that say it might play into that.
Cousin Dave at August 4, 2016 12:42 PM
"I've seen a study somewhere that said that people who floss regularly have a lower incidence of congestive heart disease."
The studies I saw showed a link between gum inflammation and congestive heart disease. The issue wasn't bacteria entering the blood stream but that long term inflammation response anywhere in the body caused heart issues. Gums were just a common inflammation spot.
If you use a 'medium' strength toothbrush you can over stress your gums and wear them down the teeth. Unfortunately it doesn't look like gums regrow so the damage is permanent.
Ben at August 4, 2016 5:15 PM
Leave a comment