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A new kind of toothpaste has come onto the scene, challenging fluoride’s #1 seat at the cavity-defense table. But does hydroxyapatite (HAp) really work to protect and strengthen teeth? Is it safe? Should you use it?
In this article, you’ll learn how HAp toothpaste works, why I recommend it over fluoride for optimal oral health, the benefits (including whiter teeth!), and which brands to try.
If you’re done with fluoride and ready to move onto something better and fluoride-free, this is the toothpaste for you.
(Two quick notes: One, in the studies I share within this article, toothpaste is called a “dentifrice” and cavities/tooth decay are referred to as “dental caries.” Second, when I compare HAp to fluoride, I’m referring to topical use only. As of right now, there is no alternative for fluoride in water, as HAp is unstable in water.)
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What is hydroxyapatite?
So, let’s start with the burning question: What exactly is hydroxyapatite, and why is it in toothpaste?
Hydroxyapatite (HAp), in its natural form, is a form of calcium that makes up 97% of your tooth enamel and 70% of the dentin of your teeth. The rest of your enamel is actually composed of water, collagen, and other proteins.
The chemical formula for hydroxyapatite is Ca5(PO4)3(OH).
Fun fact: hydroxyapatite is also the major (60%) component of bones. In addition to toothpaste, it’s been used in osteopathic research to help strengthen bone material. It also shows promise for orthodontic restorations.
The high HAp concentration in tooth enamel is the reason it’s so strong.
Hydroxyapatite Toothpaste for Tooth Remineralization
The main draw of hydroxyapatite in toothpaste is that it helps to remineralize (rebuild) tooth structure without any known side effects.
Tooth decay grows and destroys teeth when the remineralization of your teeth outweighs demineralization. Both of these processes happen all the time in your mouth and are impacted by mouth breathing, your diet, your oral hygiene, and ultimately, your oral microbiome.
You can heal cavities and prevent new ones from forming by remineralizing your teeth. Hydroxyapatite is one very effective way to do that.
The reason most dentists make a big deal about fluoride is because it’s one of the only substances on earth that can help rebuild your teeth. They think it’s better than calcium, as it’s more resistant to acid and less likely to dissolve in the presence of low pH conditions.
I explain the significant differences between fluoride and HAp later in this article, but the biggest problem with fluoride is that it’s toxic in large doses and associated with increased risks of at least 11 medical conditions.
For the most part, the biggest fluoride issues have to do with ingesting it via water, as most people spit out their toothpaste. If your child swallows a little bit of toothpaste, it’s usually not going to be a long-term problem.
Fortunately, hydroxyapatite is biocompatible with your teeth — because it’s literally the same material as the majority of your tooth structure!
Not only is it biocompatible, but it’s totally non-toxic — no Poison Control warning needed — and strengthens teeth. In fact, it’s not just compatible with your body — it’s literally “biomimetic,” which means your body recognizes it as familiar structure that belongs there.
The best way to use hydroxyapatite toothpaste to prevent and reverse cavities is to leave it on your teeth after brushing. Translation: Don’t rinse your mouth after brushing with HAp.
How does hydroxyapatite toothpaste work?
HAp acts by replacing the minerals your teeth lose when they’re demineralized and filling in the tiny “fissures” or “scratches” in your teeth that otherwise play host to bacteria.
Because your teeth recognize this compound, they absorb and uptake hydroxyapatite down to the root. This is most beneficial when we’re talking about tooth decay because HAp can reach down into the furthest area of decay to rebuild enamel on any tooth surface.
The way your teeth react to hydroxyapatite toothpaste also makes them more resistant to plaque buildup and “acid attacks”/enamel erosion that leads to tooth decay. It can even make them look “glossier.”
5 Benefits of Hydroxyapatite for Teeth
1. It can prevent and heal cavities.
Every time HAp has been pitted against fluoride toothpastes, it either performs equally well or better as a remineralizing agent.
It increases the microhardness of human enamel and prevents and reverses enamel erosion more effectively than over-the-counter fluoridated toothpaste.
HAp was successfully able to shrink lesions of decay (called “caries lesions” or “carious lesions”) on teeth and improve enamel remineralization in a study conducted in Japan. According to the authors, the more hydroxyapatite in the toothpaste, the better it restored the enamel surface.
In 2019, a study found that the use of hydroxyapatite toothpaste actually created a coating on the teeth more sturdy than that formed by fluoride toothpaste. This helped to strengthen enamel for future resistance to breakdown.
And unlike fluoride toothpaste, hydroxyapatite toothpaste won’t ever cause fluorosis.
2. It’s non-toxic & biocompatible.
One of the biggest drawbacks of fluoride toothpaste is that fluoride, at high doses, is a neurotoxicant (a toxin that impacts the brain). However, hydroxyapatite toothpaste is a biocompatible substance that your body recognizes as something that belongs there.
The CDC found that most kids use far more toothpaste than they should. This is a big problem when you’re talking about toothpastes with hundreds of times the amount of fluoride than is found in water.
But it’s not a problem with HAp.
Hydroxyapatite particles are “biomimetic,” meaning they mimic the body’s own familiar materials. They’re wildly unlikely to cause any sort of negative reaction.
Some kinds of HAp toothpaste are made with nano-hydroxyapatite. This tiny kind of particle is not naturally occurring and has to be created synthetically. However, there is no evidence that these synthetic particles are less biomimetic or toxic in any way. (You can read more about HAp sizes below.)
3. It may help teeth appear whiter.
Without any whitening ingredients, hydroxyapatite toothpaste may help to brighten and whiten your teeth.
Toothpaste is, as I’ve said many times before, a polishing dental product. This means that it isn’t necessary for the disorganization of the bacteria on your teeth (which is the point of brushing teeth) but is actually meant to polish teeth.
It can also be used for additional benefits, such as aiding remineralization (in a way similar, but not the same, to fluoride’s action).
One of these benefits is an increased whitening effect. While HAp doesn’t change the “polishing” activity of toothpaste, it adds a whitening element not otherwise seen by standard toothpaste.
HAp literally “fills in” the enamel of your teeth with healthy tooth structure, altering the appearance of teeth to be whiter.
4. It’s good for the oral microbiome.
Using HAp toothpaste will help protect your teeth from “acid attacks” by bacteria, but without wrecking your oral microbiome. Fluoride, on the other hand, is bactericidal and tends to kill off bacteria in the mouth.
Many oral care products think that by eliminating bacteria, they’re improving the health of the mouth.
The oral microbiome needs a good balance of bacteria to function properly and keep your mouth healthy. Agents like chlorhexidine, alcohol, or triclosan may temporarily alleviate bacterial overgrowth problems, but they cause far more issues over time than they help.
Hydroxyapatite particles in toothpaste prevent bacteria from attaching to the enamel of teeth just as effectively as antibacterial agents, but without killing the actual bacteria.
This is a huge benefit, as bacteria congregating on your teeth in one area is what leads to “acid attacks” (when bacteria “poop” out the high-carbohydrate food particles in your mouth). Those attacks are what cause tooth decay.
Not only does it help prevent acid attacks, it won’t destroy your precious oral microbiome.
5. It’s resistant to acidic pH.
The pH of the mouth should remain slightly alkaline to avoid inflammation and oral disease.
HAp toothpaste helps teeth become more resistant to acidic pH within the mouth, which would otherwise dissolve and break down enamel more quickly.
6. It may improve gum health.
Improvements seen included plaque control, bleeding gums, and pocket depth.
Micro-Hydroxyapatite vs. Nano-Hydroxyapatite
Hydroxyapatite toothpaste was originally developed synthetically using nano-hydroxyapatite particles. Because nano-HAp has been around longer, there’s more research to support its effectiveness.
However, micro-hydroxyapatite is also available in some toothpaste brands.
First things first: both nano- and micro-HAp powerfully remineralize teeth.
Toothpastes using nano-Ha have particle sizes between 20-80 nanometers (nm). These are significantly smaller than the dentinal tubules that make up the dentin of your teeth.
Fun fact: The astronauts who first benefited from HAp used nano-hydroxyapatite toothpastes.
While there is some concern because nano-HAp is “synthetic” and “nano” sized, these concerns are based on a false premise.
Second, high-quality nano-HAp should be rod-shaped, not needle-shaped. Most concerns around nano ingredients in cosmetics have to do with the way these particles can penetrate parts of the body where they don’t belong, causing damage.
Plus, as an added benefit, nano-hydroxyapatite particles dissolve as soon as they hit the stomach. That means if you swallow some of your toothpaste, there won’t be tiny particles going anywhere you don’t want them to go.
The main benefit of nano-HAp is that it’s likely more able to prevent sensitive teeth than micro-HAp. The size of the particles allows it into spaces that otherwise may experience sensitivity to hot, cold, or touch.
One September 2014 study found that brushing with a nano-hydroxyapatite toothpaste improved tooth sensitivity equal to a fluoride toothpaste after as little as 2 weeks.
The major drawback to nano-HAp is that regulations don’t allow for very high concentrations of it in toothpaste. Therefore, a nano-HAp toothpaste is unlikely to contain as much of the active ingredient as a micro-HAp toothpaste.
Micron-sized hydroxyapatite particles are 5-10 microns long, which is larger than most dentin tubules.
For those who want the most natural toothpaste option possible, micro-HAp may be the way to go.
It’s available in higher concentrations of hydroxyapatite and can be derived from all-natural materials (no synthetics). Even at the smaller size, it seems that micro-HAp successfully remineralizes teeth equally to fluoride.
There’s even evidence that it can help with sensitive teeth.
Hydroxyapatite vs. Fluoride
When comparing hydroxyapatite (in nano or micron particles), it consistently performs equally well or better than fluoride. It’s been the go-to option in Japan over fluoride toothpastes for over 40 years over sodium fluoride.
These particles work differently than fluoride.
Fluoride doesn’t actually replace minerals in your teeth; it creates a new structure called fluorapatite. Fluoride also signals to your enamel, through your saliva, to efficiently uptake more calcium and phosphate, strengthening tooth structure.
It forms its own unique material called fluoridated apatite (fluorapatite) above the surface of the tooth, which protects from dental plaque acids.
Both fluoride and hydroxyapatite seem to slow or limit the production of pathogenic bacteria in the mouth.
Hydroxyapatite can directly replace the structure lost by your teeth during demineralization (which is happening constantly, particularly if you eat sugary, acidic, or carb-heavy foods). It fills up the microscopic fissures on your enamel created by brushing and other normal wear and tear.
When you brush, HAp can bind with pieces of plaque or bacteria so that you end up spitting them out, rather than letting them remain on the teeth.
Instead of forming an external layer, like fluoride, HAp reaches down through your entire tooth to build it from the inside out. That’s one reason it’s so great for cavities — it can reach the bottom of carious lesions where fluoride can’t touch.
Finally, HAp results in smoother, whiter teeth when compared to fluoride because of how it fills the fissures and rebuilds the actual internal structure. In fact, it distinctly increases the microhardness of previously demineralized lesions.
Even if you’re still using fluoride toothpaste, it’s a good idea to switch to HAp toothpaste if you’re someone who may be at higher risk for fluoride toxicity. This generally includes pregnant moms, children, and people who are commercially exposed to fluoride.
The Best Hydroxyapatite Brands
There are two HAp toothpaste brands I recommend to readers. I encourage you to check them out and see which one is right for you.
RiseWell Kids’ Mineral Toothpaste (birthday cake flavor)
RiseWell HAp Floss (the first ever HAp floss!)
How do you use hydroxyapatite toothpaste?
Just like any toothpaste, squeeze a pea-sized amount onto your toothbrush and brush your teeth for at least 2 minutes.
For best results, don’t rinse with water after you brush. This leaves the hydroxyapatite coating on your teeth for the strongest remineralizing effect.
Does HAp toothpaste have side effects?
There are no known side effects of using HAp toothpaste. In (incredibly rare) cases, people may be allergic to these toothpastes, but that’s typically due to other ingredients in a full toothpaste formulation, not the HAp itself.
How long have people been using this kind of toothpaste?
NASA created the first hydroxyapatite toothpaste in 1970. In 1978, Sangi Co., Ltd. acquired the patent and began manufacturing it.
Over the next 30 years or so, Sangi’s toothpaste was studied extensively and beat cavities over and over again. Japan’s toothpaste market is dominated by HAp and has been for decades.
In 2015, the first “cavity-reducing” toothpaste released with HAp (and without fluoride) outside of Japan was X-PUR Remin, sold in Canada.
In 2017, Boka was the first hydroxyapatite toothpaste brand to launch in the United States.
Isn’t nano-hydroxyapatite synthetic? Why would you recommend a synthetic chemical in my toothpaste?
While nano-HAp is technically synthetic, there is no evidence that it’s dangerous to human health.
What does hydroxyapatite toothpaste taste like?
Depending on your toothpaste brand, HAp toothpaste may taste like just about anything. RiseWell’s kids’ flavor is a vanilla birthday cake, while Boka sticks to the more traditional mint flavor you’re probably used to in toothpaste.
These flavors are impacted by other ingredients, such as xylitol or other sweeteners, essential oils, or other flavors.
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