A Stupidly Simple and Effective Toothbrushing Trick You Should Do, But Don’t

You’re brushing your teeth wrong.

I’m not talking about the type of toothbrush, size of the brush head or your actual brushing technique. No. I’m talking about something more effective and ridiculously simple. Don’t worry, my brushing behavior was wrong, too, but I’ve since fixed it, and now I’m reaching out to help you.
Because if you’re like me, you have at least one or more of these feelings when it comes to the dentist:
  • At each visit, you truly believe you have a 50-50 shot at getting a cavity (yep, that’s been me!).
  • You fear the dentist. Maybe it’s from induced gagging due an uncomfortable fit due to impression material or gel treatment. Maybe it’s due to the sound of the excavating drill, a shot of numb-numb juice, whatever. You have a fear.
  • You bear an innate distrust of the dentist or hygienist (or even both!).
Fortunately, you’re not alone: I’m in the same boat.
I was constantly battling against either the destruction of my teeth or sensitivity to foods or drinks. In fact, my gradual but steady decline in tooth health ultimately rendered me so frustrated that I switched my scientific gearbox from research involving batteries, polymeric materials, and even ice (yes, I’m serious) to figuring out how I can help thwart tooth decay. And not just for me, but for you, my family, anyone who had a history of tooth decay.
That was almost 15 years ago. Thankfully, I’m in a different place now, having spent more than a decade in oral health research (e.g., a dental school appointment and partnerships with esteemed researchers, including a man I consider one of the original godfathers of fluoride toothpaste).
Here, I’m revealing a simple strategy that will supercharge your toothbrushing benefits starting right now. And, it’s easy: you don’t have to buy anything and you don’t have to add another step to your daily oral hygiene practices. But, I must ask you to have an open mind.
Who am I writing to? Specifically, I’m directing this message to those who have nagging dental decay (i.e., ‘dental caries’), tooth wear (e.g., erosion), or sensitivity, to the point where, food and drink options are limited (example: you wistfully drink lukewarm beverage, incapable of enjoying ice-cooled refreshment on hot, muggy days; or worse, yet: you love ice cream, but fear the frozen bite) and your probability of the dentist finding something wrong with your mouth gradually – but surely – tips in favor of the dental ‘house’.
In fact, in many ways, going to the dentist is akin to visiting the car mechanic: we don’t want to go, we don’t fully trust the prognosis but need the problem fixed so we accept it (along with the incurred expense); and, although we don’t want to, we will eventually be forced to return when another problem arises.
Of course, there’s always cost considerations, but money or insurance doesn’t make this problem go away forever – it may fix the problem now, perhaps buying you some time, but years later something will break down.
I mean, unless we’re eating from a tube, participating in monk-like focus to solely subsist on liquids and non-solid foods, or smiling with knocked-out/missing teeth for whatever reason, our chompers are expected to perform as efficiently as possible for as long as possible. Why? Because the fixed, modified, or otherwise replaced analog isn’t as good as the original.
Dear reader, the constant struggle to keep our teeth and dental work in optimal condition is real. And just because you weakened tooth gets fixed doesn’t mean it’s the end of your concerns. In fact, they’ve just begun.
In reality, fillings are not a permanent solution, and repairs are usually needed: your newly placed filling might last 10 years (note: composite fillings, which are especially common for various reasons, fail more quickly than amalgam fillings).  The two main reasons for failure: continued decay in/around/under the restoration and restoration fracture.
Within the dental community, fillings (known broadly as ‘restorations’) placed due to dental decay (i.e., dental caries, or cavities) are known to trigger the so-called ‘death spiral’. This moniker derives from the fate of a decaying tooth where aggressive intervention leads to irreversible loss of tooth structure occurs each time a dental drill and/or acid application is used to ‘prep’ the tooth for the filling.
It’s true. I know firsthand, and I don’t even grind my teeth (which can expedite failure)! I recently had a filling fail (if your curious, it was a composite filling), almost detaching completely from my tooth in the midst of a nighttime flossing event. I was initially confused, then surprised, but soon alarmed when I discovered this loose bit was not a popcorn kernel or other foodstuff: no, there it was, this cleaved bit of tooth-like material remaining somehow wedged yet easily ‘wiggleable’. Fortunately, there was no pain.
My trip to the dentist the next morning confirmed the existing filling failed, which in turn necessitated a replacement filling (again, thank you for your services, Dr. Chris!). So notching another twist in that tooth’s ‘death spiral’, I’m well aware that subsequent repairs are destined to result in further tooth loss.
So how can you improve the chances of saving your teeth, prolonging your fillings and other serious dental work, get more out of toothbrushing, all without additional steps?

Here’s the secret:

Immediately after brushing, spit out the paste. But, don’t rinse.

Boom! That’s it. That’s the not-so-glamorous secret.
I know, I know. It sounds like a stupid trick. Silly and simplistic.
But think about it: has anyone (e.g., dentist or hygienist) told you explicitly not to rinse after brushing?
After you brush your teeth – no matter how long you brush your teeth, whether it’s 5 seconds or 2 minutes (and if longer, may the dental gods bless you!) – do not rinse your mouth out so the toothpaste’s agents can work their ‘magic’.
Just spit out the toothpaste-saliva slurry when you’re done brushing. You can wipe away slurry dribbles from your lips with water, but don’t rinse out your mouth.
Unless your teeth are in pristine condition, this is probably the best toothpaste advice anyone can give you.
(Note: for concerns about accidental swallowing (this especially pertains to children), of course, rinse if/as needed. Just don’t eat the toothpaste. Bad things happen when you eat toothpaste.)

Why is that so important?

For those that never rinsed after brushing, do you know why it’s important? Has anyone explained it to you?
Any fluoride treatment you’re given at the dental clinic (e.g., perhaps when you were a child, perhaps you and/or your child receives in-office fluoride treatments) accompanies instructions to ‘not eat or drink anything for at least 30 minutes’ (or, something similar). Well, it’s no different with toothpaste. It’s just that you are self-administering the treatment, not the dentist or hygienist.
Like any treatment (medicine or otherwise), it takes a bit of time to let the ‘agents’ react with the target surface. For example, if you were to stain your deck, paint your house, or seal your pavers, you wouldn’t apply the treatment on a rainy day or if rain is expected. Similarly, you wouldn’t wax or paint your car with the pending threat of rain.
Well, the same holds true for the agents in your toothpaste designed to help your teeth, such as fluoride, potassium salts (e.g., potassium nitrate), xylitol, peroxides and so on. If you’re rinsing, you’re missing out on toothbrushing benefits.

Does it matter?

Here’s an example of how much fluoride is washed away after rinsing compared to no-rinsing after a professional (i.e., in-office treatment) gel treatment: approximately 59% less fluoride was detected in the mouth after rinsing compared to simple spitting and no rinsing; in fact, even after 21 days, fluoride uptake into the tooth was greatly reduced by about half compared to the no-rinse group.
And what about my detached filling? It endured 10+ years: not bad, given the odds above. But then again, I’ve been rinse-free for almost a decade, and regularly use prescription-strength toothpaste (which has more fluoride), two aspects that can extend the life of restorations.
Makes sense, right?
But, does it really matter how much fluoride remains?
Yes, it matters! Here’s why:
Maintaining fluoride in the mouth is a great way of preventing tooth decay while providing a mechanism to help thwart the microscopic mayhem that ordinarily results from undisturbed ‘plaque traps’. That’s right: you gotta keep the bacteria in check.
Let me clarify.
The reason you are prompted to floss or ‘brush better’ isn’t so the dentist, hygienist or assistant can avoid the gunk stuck in your teeth as they conduct their intraoral business. Of course it helps to have a clean mouth, but it’s not recommended for their benefit – it’s for your benefit.
If plaque is left to accumulate – whether it’s around your fillings, crowns, orthodontic brackets, even in between your teeth – the chances increase that the bacteria responsible for tooth decay will have a supportive environment favoring acid production that leads to loss of tooth mineral (i.e., demineralization).
Think about it another way: if you suddenly found yourself with zero responsibility and penalty-free behavior, your latent hedonism would be difficult to suppress (at least, I know mine would!).
It’s the same with the bacteria that occupy, multiply, and acidify in these plaque traps (i.e., ‘unclean’ areas). This is one reason why fluoridate toothpaste is recommended: it disrupts plaque (i.e., the bacterial ‘home’), thereby reducing decay risks.
But, it’s really hard, impossible even, to achieve a clean mouth!
Yes, I agree with you. And this is where having fluoride linger for as long as possible can boost protection against bad-breath and tooth-decaying microbial milieu.
This is one reason water fluoridation works so well. In ages past (you know, like last millennium), drinking bottled beverages (including water) was not as common as drinking tap water. So through frequent ingestion of low, safe levels of fluoride, tooth decay is dropped by about 25% simply from drinking tap water.

How does it work?

Fluoride has multiple modes of action (even very low levels (~ 1 ppm) found in drinking water), including the acid-producing ability of certain bacteria responsible for tooth decay. Higher levels of fluoride, like those in conventional fluoride toothpaste (~ 1,000 ppm), provide additional benefits, such as limiting bacterial growth. In fact, these effects become super-sized for prescription-strength fluoride toothpaste (~ 5,000 ppm fluoride), where the risk for tooth decay drops by a whopping 75%: there is less plaque, less bacterial growth, less tooth-dissolving acid production, less, less, less.
By avoiding post-toothbrush rinsing, there remains more fluoride available to disrupt ‘bad’ bacterial behavior (e.g., acid production and bacterial growth). Such a sustained benefit also improves tooth remineralization (i.e., the replacement of lost minerals).
The surefire reaction upon revealing the spit-but-don’t-rinse secret is always the same:
“Why didn’t they tell us this?”
In all likelihood there are many reasons. For instance, the dentist (or hygienist) may think it’s obvious, or has told you previously during an appointment but you didn’t remember it. Or, there may be concerns about accidental (or, purposeful) swallowing of fluoride toothpaste when you’re young (i.e., 6 years old and younger) – to help reinforce this is not the case, recommendations may be to rinse (in fact, this is often given as ‘directions’ on the toothpaste). Excessive fluoride ingestion could be toxic: of course, ingesting too much of most things cause toxic effects, even water or oxygen – I mean, that is why it’s called ‘overdosing’.
While an age-appropriate ‘right’ time to stop rinsing is debatable, unless one is regularly eating toothpaste, or drinking water with unsafe levels of fluoride, the risks for fluorosis and systemic poisoning are low. Once permanent teeth emerge (generally by 12 years of age), the concerns for fluorosis become moot (i.e., fluorosis develops from systemic ingestion, not topical application). But certainly by adult age, it is unnecessary to keep rinsing!

Are you ready to go rinse-free?

Now, if the flavor, feel, texture, etc. of your toothpaste renders ‘no rinsing’ too challenging, perhaps you need to change your toothpaste. After all, not every toothpaste contains flavor-bursting chemicals and potent concrete-like aggregate designed to brusquely abrade layers of slime from your teeth. In fact, I strongly recommend gentle but effective cleaning with just enough flavoring and foaming to let you know the toothpaste is ‘working’.
Now, for those of you blessed with perfectly healthy teeth, nary a problem even with sensitivity to cold or hot foods or drinks… then good for you! (though I’m a bit envious!J)
But, I know I’m not alone since 91% of adults (between 20 and 64 years of age) have tooth decay.
So if you’re in the ‘caries club’ like me but are guilty of post-brush rinsing, then do your teeth and dental work a favor: break the habit and go rinse-free.

About the author: Dr. Karlinsey strives to be a catalyst for improved oral health behavior in order to wipe out tooth decay, the single most preventable disease affecting mankind. Inspired by his own tooth decay, his grant-winning research helped him create tooth-strengthening inventions currently found in several market-leading dental products. He is an expert in preventive dentistry and serves as an oral health resource for professionals and laypeople alike. To learn how teeth are affected by foods, fluoride, and more, check out his new book available on Amazon.


Robert L. Karlinsey, PhD

Dr. Robert L. Karlinsey earned a BS in Physics and PhD in Chemical Physics, holds several patents, and has published in multiple fields including dentistry, chemistry, and materials science. His lifelong struggles with his own dental decay ultimately inspired him to investigate the remineralization of teeth.