When To Brush, Floss And Swish, According To Dentists

Today's burning question is a collection of dental quandaries that grew out of a discussion among Lifehacker staffers, where it turned out that each of us -- and some of our dentists -- have very strong opinions on the right time and order for the various steps of dental hygiene. The more we chatted, the more confused we became.

Illustration: Chelsea Beck/GMG

It started with this revelation:

my dentist just yelled at me for brushing my teeth AFTER breakfast instead of BEFORE

"you should brush right when you wake up, otherwise it's like you're eating off a dirty plate"

did... anyone know this?

I sure as hell didn't!

On the one hand, your mouth is gross when you wake up (especially if you wear a night guard or retainer). On the other, what's the point in brushing and then immediately going to the kitchen to dirty your teeth? One thing led to another, and soon we were debating a different point:

related Q: does it matter if you floss before or after brushing? My dentist says to floss after, but I wonder if that's because you're more likely to keep flossing if you see how much it gets that brushing missed.

I always thought of flossing as a finishing touch on the main cleaning job, but the floss-first camp has some very dedicated adherents. And then someone dropped this bombshell:

We've been through this. Don't mop a dirty floor. Floss first.

Rinse with mouthwash, then brush.

With mouthwash as a variable, any hope of reaching a friendly consensus was lost. It was time to call in the experts.

Brush Before Breakfast If You Can

There's no evidence behind the fear that morning-mouth bacteria will make you sick if you eat them along with your breakfast, so brushing first thing in the morning is optional. Although now that I think about that way, a pre-brushing breakfast sounds kind of gross.

The one time to avoid, if you can, is brushing right after breakfast, if your breakfast involves orange juice or anything really acidic. (Coffee is fine, though.) The acid in the food interacts with the enamel on your teeth, so you could be doing microscopic damage to the enamel if you brush right away.

Ideally you'll either brush before breakfast, or wait a little while afterwards -- 30 minutes should be fine -- before brushing. You can swish some mouthwash in the meantime if you like.

But don't worry too much. "This is a 'how many angels on the head of a pin' type of discussion," says Dr. Grant Richey, a dentist who regularly writes about science-based dentistry, "I don't think I've ever seen a patient whose enamel has been worn away that I would say 'oh if you just would have waited 30 minutes after drinking that orange juice this wouldn't have happened.'"

Better to brush after breakfast than to not brush at all. I mentioned a co-worker who brushes after drinking orange juice and Dr. Richey said "I bet when he's 100 years old, he'll still have enamel on his teeth even though he's doing it all wrong."

Floss Any Time

There's no scientific consensus on whether to brush before or after flossing. Dr. Richey says he personally does both: brush-floss-brush. But he stresses that's not necessary, and either way is fine.

"Look, as long as you are brushing twice a day with a fluoride toothpaste, and flossing or using another interdental cleaner twice a day, you're good to go," says Dr. Alice Boghosian, a spokesperson for the American Dental Association. "God bless people if they feel comfortable flossing after they brush, as long as they're cleaning between their teeth once a day."

Mouthwash Comes Last

"Mouthwash is not a necessary step to maintain good oral health," says Dr. Boghosian, so if you just want the basics, you can stop right there. Most mouthwashes just exist to make your breath smell clean and nice, so she says it makes sense to make a mouthwash the last step. That way, the fresh feeling can linger.

Some mouthwashes have a special purpose, though, and Dr. Richey says he'll recommend them based on somebody's oral health. Listerine is good at killing germs, and there are stronger mouthwashes a dentist might prescribe. Use those however your dentist says to use them, which will probably be last in the sequence.

Fluoride mouthwashes, which strengthen the enamel on your teeth, also work best if they come last. This way, the fluoride sits on the surface of your teeth as long as possible.

Ultimately, both dentists agreed that if you're asking these questions at all, you're doing just fine. It's the people who don't brush or floss regularly that they're worried about.


    Flossing first clears off bits of food that the fluoride from the toothpaste won't otherwise be able to reach. Then again, flossing hasn't actually been scientifically validated as being effective (because no one's bothered to study it, possibly because it seems so bloody obvious)

    Last edited 03/03/18 4:55 pm

    What about WaterPik. How good (or otherwise) is it? It certainly dislodges an amazing amount of stuff from between the teeth.

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