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  • Jason Arandia DMD

Do I Really Need To Floss?

It happens every day. A patient comes in for a regular check up. Immediately she sheepishly confesses, wracked with guilt, "I know I need to floss more." It seems the patients understand that flossing is good for their oral health, yet very few people do it. So do you really need to floss?

Last year an article was published by the Associated Press that raised a lot of eyebrows entitled "Medical Benefits of Flossing Unproven." The article looked at the available research on flossing and concluded there was insufficient or weak evidence to support flossing. Guess what? It's true. There isn't enough high quality research. The main reason is that conducting a study of flossing is nearly impossible.

The gold standard in evidence-based medicine is the Randomized Double-Blind Controlled Clinical Trial. The ideal experiment would be large scale, thousands of patients in different geographic locations and tracked longitudinally for several years.

The patients would be split into two groups, flossers (experimental group) and non-flossers (the control goup). Flossers must floss every day. Non-flossers must NEVER floss, not even if a piece of popcorn gets stuck between the teeth, a chunk of steak gets snagged on an old filling, or when that patient comes in for routine dental work. Flossers that skip flossing are thrown out of the study as well as non-flossers that floss occasionally.

Since the subjects actually know what test category they are in, the concept of "Double-Blind" no longer applies. Double-Blind means the researchers and the test subjects do not know what test group they belong to. When an experiment is not double-blinded, it can lead to bias in the data, especially if the subjects are self-reporting as is the case in large studies. "Have you been flossing every day?" "Yes, of course!"

Test subjects must report for evaluation periodically to measure outcomes. Getting people to come in once a week, or month, or six months to have their gums probed and x-rays taken is challenging and patients drop out of the study.

Even just getting this experiment approved by an ethical review board will be difficult, largely because the control group would be deliberately subject to harm. We expect them to get cavities, gum disease and infections more often than the test group.

So now you can see why the evidence is weak. It is simply not easy to do the research. Available studies are conducted on small sample sizes over short periods of time with biased limited data and subjects are put at unethical risk.

OK, I get it, but do I really need to floss?


Here are the scientifically proven facts:

1. Brushing alone only removes 60% of plaque and food buildup. Flossing helps to get rid of the rest.

2. Plaque contains bacteria.

3. Bacteria cause cavities and gum disease.

4. Removing food and bacteria from teeth prevents cavities and gum disease.

That's really all you need to know. I made a handy Venn diagram to help you understand the various factors that influence cavity formation and gum disease.

If you have questions about flossing or just need a check up, contact us at 617-232-7399

Dr. Jason Arandia treats dental patients in Boston, Brookline, Brighton, Waltham, Newton and Watertown. He received his general anesthesia training at Hartford Hospital and is licensed to practice moderate conscious sedation and nitrous oxide analgesia. Dr. Arandia is a member of the Dental Organization for Conscious Sedation (DOCS).

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