"Should You Floss Before or After You Brush?"
Over the years, it has been generally accepted that the use of dental ﬂoss
has a positive effect, removing up to 80 percent of plaque.
How do we know?
You can use what’s called a “splitmouth” design,
where each person can act as their own control,
for example only flossing one quarter of their mouth.
They asked study subjects to stop brushing their lower jaw
so that plaque would build up; then they were randomized
to floss half and leave the other half as the non-flossed control.
After three weeks, not only did the flossing cut plaque
about 60 percent, more importantly it cut signs of gingivitis in half—
bleeding on probing and another index of gum inflammation.
Note, though, this is comparing flossing to nothing.
They weren’t allowed to brush the jaw.
So yeah, flossing is better than nothing,
but is flossing plus brushing better than just brushing alone?
The advocacy of ﬂoss hinges, in large part, on common sense,
but common sense doesn't go very far as a form of evidence.
You don’t really know...
until you put it to the test.
What’s the efficacy of dental floss in addition to a toothbrush?
Surprisingly, only 3 out of the 11 studies they looked at
found a significant added benefit.
The anti-flossers were positively giddy,
comparing dentists who continued to advocate
flossing in the face of the data to flat-earthers.
Dentistry is a profession in denial.
Over 80 percent of people don’t floss regularly,
and it’s just hard for the “dental elite” to accept that
the “great unflossed masses” were right and us doctors were wrong.
Flossing doesn’t work—get over it!
So, you’ve heard of the tooth fairy. Is flossing just some tooth fairy tale?
This review was published back in 2008. Since then, more studies were published
and while the evidence on additional plaque reduction is weak,
at least there’s some evidence it helps with gingivitis,
which is a primary reason you want to reduce plaque anyway.
Why might they have not found stronger evidence?
Well, the trials were of poor quality;
and so, the conclusions must be viewed as unreliable.
So, basically we don’t have good evidence either way
because good studies really haven’t been done.
Why not? Why wouldn’t Big Floss fund the studies?
Because it appears that all floss works the same.
If you compare unwaxed to woven to shred-resistant floss,
they all have about the same plaque-removal efﬁcacy,
which it appears all such studies found.
So, why would a floss company fund a study to show
flossing in general is good if they can’t show their product is better-
otherwise you might just go buy their competitor’s floss.
Where do we stand today?
Although technically the evidence for ﬂossing is weak,
more importantly, the methodology of the studies
examining ﬂossing effectiveness are also weak.
For example, they didn’t assess the quality of people’s flossing.
This, for example, is not the way to floss (don’t ask—it’s a long story).
Bottom line, the American Dental Association continues to recommend
brushing and flossing every day.
But what’s the proper sequence?
Should you floss before or after you brush?
Some dentists argue that ﬂossing should come ﬁrst
because you stir up the particles and plaque
that the toothbrush can then brush away,
and then the ﬂuoride from the toothpaste might get in there better.
But others recommend brushing ﬁrst, thinking that that would remove the bulk
of the particles first, and then the floss could like
floss some of the fluoride from the residual toothpaste in there.
You don’t know …
until you put it to the test.
“The eﬀect of toothbrushing and ﬂossing sequence
on between-tooth plaque reduction and ﬂuoride retention:
A randomized controlled clinical trial and…
flossing first won, in terms of getting rid
of significantly more plaque and getting more of the fluoride in there.
When we ﬂoss after brushing, much of the particles that are
being pushed out by dental ﬂoss may stay in place on our teeth.
The bottom line is ﬂossing followed by brushing is preferred.