Is Hydroxyapatite Safe? Uncovering the Truth in 2024 (2024)

Dr. Michelle Jorgensen

• February 7, 2024

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Holistic Health and Wellness

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There is a new player in the oral health care product area called hydroxyapatite.Nano hydroxyapatite and micro hydroxyapatite have been added to oral care products without a lot of explanation and have created controversy in the industry . . . and left many asking the question: Is Hydroxyapatite Safe?

Everyone wants cleaner, stronger, whiter teeth and healthy gums., but is hydroxyapatite the magic ingredient some claim to help deliver these results?

Are there safety concerns we should be aware of?

Scores of research articles have given us answers to these questions.

I’ll explain how…

• The right kind of hydroxyapatite
• Used in the correct amounts
• And with the correct methods

…has incredible benefits for the mouth and the body over comparable products of the past.

Let’s dive in and uncover the truth: is hydroxyapatite effective and safe to use in 2023?

Have you ever wondered what makes our teeth and bones so strong?

Hydroxyapatite is a mineral form of calcium apatite (calcium phosphate), and is a key component of both teeth and bones.

The exact composition can vary, but in general, hydroxyapatite crystals make up about 70% of the weight of our bones and 96% of the enamel on our teeth. That same naturally occurring organic material is now being used in tooth products for remineralization and repair.

Hydroxyapatite can come from natural sources, including…

• Cow and other animal bones
• Egg shells
• Fish scales

…or it can be synthesized in a lab.

Due to common concerns with animal products, as well as sterilization, purity, and processing challenges, most hydroxyapatite that is used in dental care products is synthesized.

This process creates a very small, pure product that can be safely used in the mouth. There are two common sizes in mouth care…

…nano hydroxyapatite, and micro hydroxyapatite…

…and both have been used in dentistry.

Nano hydroxyapatite refers to hydroxyapatite particles that range from 1 to 100 nanometers in size. 1 These particles are EXTREMELY small, providing a higher surface area compared to larger particles.

Micro hydroxyapatite, on the other hand, refers to hydroxyapatite particles that are larger, typically ranging from 100 nanometers (nm) to 10 micrometers (µm) in size. Micro hydroxyapatite particles are still small compared to many other particles, but they are significantly larger than nano-sized particles.

So, how exactly does hydroxyapatite work in dental health products?

The science behind it is fascinating. When the enamel is exposed to acids (either produced by bacteria in the mouth or from acidic foods and drinks) minerals are pulled out of the tooth surface.

This is called demineralization.

This leaves the tooth susceptible to attack from bacteria . . . which leads to tooth decay or cavities.

Remineralization is the process of putting minerals BACK INTO the enamel, repairing and strengthening it.

When hydroxyapatite particles come into contact with the tooth enamel, they release calcium and phosphate ions.2 These ions interact with the minerals in the enamel and saliva, leading to the formation of a new layer of apatite crystals on the tooth surface.

This new layer leads to some expected and some surprising results:

• Remineralization (repairing and strengthening teeth): The mineral crystals help remineralize and repair demineralized or damaged enamel, and protect against future mineral loss and tooth decay.

• Desensitization (surface protection and cavity prevention): The hydroxyapatite acts as a protective barrier on the tooth surface, rapidly desensitizing the tooth and preventing further demineralization.

• Whitening and smoothing: The hydroxyapatite smooths the tooth surface by filling in microscopic pits and fissures, reducing surface roughness and making the tooth more resistant to bacteria and acid. This also leads to whitening and brightening of the tooth.

The openings to these tubules are usually covered with enamel, but that enamel can be worn away from things like…

• Tooth wear
• Gum recession
• Dental procedures

…all which lead to sensitivity and deeper tooth decay.

Studies have shown that hydroxyapatite particles have the potential to get into these dentinal tubules 3,blocking access to other substances and making the dentin layer harder, less sensitive, and more resistant to decay.

This is when particle size is important.

The hydroxyapatite particles have to be smaller than the openings of the tubules for these deeper benefits.

Dentinal tubules are 1.7 µm at the DEJ 4 . Hydroxyapatite particles that are 500 nm or smaller will fit well inside the tubules, but larger hydroxyapatite particles will most likely only remineralize the enamel surface of the tooth.

You will want hydroxyapatite products that contain 100 nm-500 nm size particles (considered micro hydroxyapatite) for the most benefit.

First used in toothpaste in Japan in the 80s and 90s, hydroxyapatite toothpaste has only recently gained international attention. Some products with hydroxyapatite are FDA approved for use…

…but as with any new product, there are questions about whether they live up to the claims.

Do hydroxyapatite toothpaste products really work?

Are they safe for long-term use and are there any potential risks with these tiny particles?

The use of hydroxyapatite in dental products has sparked a debate among dental professionals and consumers alike . . . raising questions about its effectiveness and safety.

Below I’ll break down the published research on the topic and show you what has been discovered.

Enamel is the hardest mineralized structure of the human body, and is made of crystals. Water and mineral ions pass right through the enamel crystals, leading to minerals being lost and added (demineralization and remineralization), throughout the life of the tooth.

Does hydroxyapatite add these minerals back to the tooth?

Decades of research have shown definitively that yes, hydroxyapatite is effective in remineralizing teeth, strengthening, protecting and even repairing teeth. 2,5,6,7

In fact, in a 2022 study, hydroxyapatite, as well as combinations of fluoride and calcium phosphate were shown to all remineralize the teeth, but the “hydroxyapatite showed the highest remineralization potential”.6

A recent study investigated the desensitizing activity of nano hydroxyapatite toothpaste. The conclusion was that “The hydroxyapatite toothpaste tested caused a reduction of hypersensitivity/pain values higher than conventional fluoride toothpaste.”8,9

And the great news for sensitive tooth sufferers is that research shows that hydroxyapatite not only “effectively reduced dentin hypersensitivity, but the effect was instant and long-lasting.” 10

One of the surprising benefits of hydroxyapatite is its ability to whiten and brighten teeth!

Participants in a study that were trying one of these new products reported “their tooth surface as smoother, tooth color as whiter, and reported a stronger feeling of freshness after toothbrushing.” 11

Another study concluded that “hydroxyapatite is a promising whitening agent for oral care formulations and represents a biomimetic alternative to other whitening agents for daily dental care.”12

This is particularly promising, as other whitening products can have undesired side effects, and the side effects of hydroxyapatite are desired, including less sensitive and more cavity-resistant teeth. 13

Better gum health is another surprising and welcome side effect of hydroxyapatite!

The gold standard for treating gum disease in dentistry is chlorhexidine. Used in a rinse, it can stain teeth, tastes bad, and can be toxic to cells. 14,15,16

The great news is that hydroxyapatite, alone (and in combination with small particles or silver in a rinse), is even more effective than the old gold standard…

…and brings all the other benefits we have already discussed!

Hydroxyapatite in a rinse with silver can:

• Stop bacteria from sticking to the teeth.17,18

• Kill bacteria that lead to tooth decay and gum disease.17,19,20,21

• Maintain healthy bacteria while improving gum and tooth health.22,23,24

When it comes to protecting our teeth from decay and strengthening our enamel . . . there is no debate that both hydroxyapatite and fluoride toothpaste help.

Fluoride and hydroxyapatite have shown similar efficacy for…

• Remineralizing tooth enamel
• Reducing the size of cavities
• And stopping progressing decay.

However, hydroxyapatite has benefits fluoride doesn’t share.

Studies have shown that hydroxyapatite toothpaste is a safer alternative to fluoride toothpaste.

Fluoride is incorporated into teeth and bones . . . and changes the crystal structure.

Too much fluoride leads to a condition called fluorosis where the teeth are spotted or “mottled” with white and brown pits and holes in the enamel.

A big concern is that there is fluoride in water, foods, and canned beverages and products. It’s difficult to know or control the dosage, and fluoride poisoning may occur with repeated use. 25,26

This is particularly concerning in young children using fluoride-containing oral care products.

There is a limit to fluoride dose allowed in oral care products to avoid the risk of fluorosis in children 26,28,29 and toxicity in all ages 30.

The fluoride dose recommended for toddlers and children is even lower than the 1000–1500 ppm fluoride concentration in non-prescription toothpaste sold in the stores. These products are not safe for children.

Thankfully there is research showing the effectiveness of hydroxyapatite as a fluoride replacement for children and adults. In a 2019 study, 10% hydroxyapatite achieved comparable remineralization and prevention as fluoride.

The study concluded, “Thus the Hydroxyapatite toothpaste is confirmed to be equal to the fluoride toothpaste in this study.” 31,32 Numerous other studies have shown hydroxyapatite to be as effective as fluoride in remineralizing and preventing tooth decay. 33,34,35

In addition, hydroxyapatite tooth products can be a great tool for teaching children about oral hygiene. Its non-toxic nature means that parents can worry less about their children accidentally swallowing toothpaste during brushing.

However, as with any oral care product, it’s important to supervise children during brushing and teach them to spit out toothpaste after use.

With all of the benefits, there is concern that these particles may have safety concerns. There is also concern about:

1. The shape of the particle
2. The percentage of nano hydroxyapatite particles in the product.

Let’s tackle these concerns one at a time…

One advantage of oral use of hydroxyapatite is that when hydroxyapatite particles are swallowed, they enter the stomach and completely dissolve.36

A study reported, “There is no risk from an oral uptake of calcium phosphate(hydroxyapatite) nanoparticles due to their rapid dissolution in the stomach.”37

The particles can also enter the body through the gum tissue, but the SCCS in Europe found that hydroxyapatite particles in numerous studies did not get into the body through intact gum tissue.1

These studies show systemic health problems are not a risk for oral use of hydroxyapatite.

The SCCS in its 2021 opinion paper also claimed possible cytotoxicity and genotoxicity, so researchers have been working hard to prove or disprove these concerns.

A later 2021 study on nano hydroxyapatite particles showed safety for cells and DNA, stating “excellent cytocompatibility and absence of genotoxicity are clearly demonstrated, rendering it suitable for commercial use.”38

A lot of concern has been raised about the shape and size of the hydroxyapatite particles and their safety.

• Bone hydroxyapatite is 40-60 nm in size and needle and plate-shaped.
• The hydroxyapatite in enamel is in hexagonal rods and is much larger, 40-1000 nm in size.39

A recent study showed that “there is no indication for a significant influence of the calcium phosphate phase or the particle shape (e.g. spherical or rod-like) on the biological response. In summary, the risk associated with an exposition to nanoparticulate calcium phosphate in doses that are usually applied in biomedicine, health care products, and cosmetics is very low and most likely not present at all.”40

What this means is that the shape and the size is less important than the dosage of the hydroxyapatite.

What percentage of hydroxyapatite is safe while delivering all of these benefits to the teeth and the mouth?

A 2019 study on toothpaste efficacy showed, “10% hydroxyapatite achieved comparable efficacy with 500 ppm F− in remineralizing initial caries and preventing demineralization. Thus the hydroxyapatite toothpaste is confirmed to be equal to the fluoride toothpaste in this study.”9

When I first started researching nano hydroxyapatite, micro hydroxyapatite, and nano hydroxyapatite toothpastes, I made a list of the characteristics that the perfect product would have.

This is the list I came up with:

1. Hydroxyapatite should be a size small enough to get into dentinal tubules (less than 500 nm)

2. Hydroxyapatite should be in a dosage of 10-15% of the product

3. Hydroxyapatite should be synthesized for purity and safety

4. Hydroxyapatite should be in a needle or rod-shaped to be biocompatible

5. Hydroxyapatite should be combined with silver particles for added gum health

Failing to find an all-in-one solution with these advantages, I opted to create my own hydroxyapatite toothpowder and mouth rinse that fulfilled my desired oral health benefits.

My Remineralizing Tooth Powder is designed to help with remineralize teeth, rebuild enamel, and eliminating tooth sensitivity.

It combines the powerful effects of hydroxyapatite with bentonite clay and healing essential oils. The remineralizing hydroxyapatite toothpowder contains:

• Calcium Carbonate

• Xylitol

• Bentonite

• Hydroxyapatite

• Mentha Viridis (Spearmint) Leaf Oil

• Gaultheria Procumbens (Wintergreen) Leaf Oil

• Plantain (Plantago Major) Leaf Extract

The hydroxyapatite in all of my toothpowders is synthesized in a carefully selected lab to be 200 nm in size and needle-shaped. It is 15% of the total formula.

This makes it easy for the hydroxyapatite particles to get into the enamel and remineralize, protect against decay and whiten, and into the dentin to desensitize and strengthen the tooth.

It is designed to maximize the remineralizing capabilities of hydroxyapatite in the safest form possible.

This mouth rinse incorporates the oral health benefits of hydroxyapatite and combined them with silver and other healing herbs.

My hydroxyapatite mouth rinse has the following ingredients:

• 10 ppm Silver Soltuion

• Hydroxyapatite

• Xylitol

• Plantain Extract

• Calendula Extract

• Marshmallow Extract

• Lavender Oil

• Peppermint Oil

The mouth rinse combines 200 nm hydroxyapatite with silver particles in solution. This creates a protective layer that prevents bacteria from sticking to the tooth, preserves healthy bacteria in the mouth, and freshens breath.

The mouth rinse also contains healing herbs to combat dry mouth, inflammation, and gum irritation.

After using, the mouth feels fresh, the teeth feel smooth and the gums are healthier.

In conclusion…

Research confirms the safety of hydroxyapatite, endorsing its use in oral health products.

As a promising fluoride toothpaste alternative, hydroxyapatite dental products boast a myriad of benefits, including:

• Enamel remineralization
• Tooth sensitivity alleviation
• Teeth whitening
• Gum health improvement

…and cavity prevention.

Hydroxyapatite proves to be a powerful tool for oral care.

I hope this article has shed light on hydroxyapatite’s significance in dental health products.

Explore my hydroxyapatite tooth powder and mouth rinse to experience the remarkable health advantages firsthand today!

1. https://health.ec.europa.eu/system/files/2022-08/sccs_o_246.pdf

2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8930857/

3. https://pubmed.ncbi.nlm.nih.gov/35871701/

4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4564583

5. https://pubmed.ncbi.nlm.nih.gov/31839988/

6. https://pubmed.ncbi.nlm.nih.gov/35836549/

7. https://pubmed.ncbi.nlm.nih.gov/34925515/

8. https://pubmed.ncbi.nlm.nih.gov/35886524/

9. https://pubmed.ncbi.nlm.nih.gov/27891458/

10. https://www.researchgate.net/publication/291334720_Efficacy_of_a_Commercially_Available_Hydrox
    

11. https://www.mdpi.com/2313-7673/5/2/17

12. https://pubmed.ncbi.nlm.nih.gov/33255509/

13. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8432723/

14. https://www.iosrjournals.org/iosr-jdms/papers/Vol15-Issue%206/Version-3/L1506035759.pdf

15. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6098817/

16. https://pubmed.ncbi.nlm.nih.gov/27082817/

17. https://www.sciencedirect.com/science/article/abs/pii/S0003996917300845?via%3Dihub

18. https://link.springer.com/article/10.1007/s00784-012-0781-6

19. https://www.hindawi.com/journals/jnm/2018/9248527/

20. https://www.walshmedicalmedia.com/open-access/anticaries-potential-of-silver-nanoparticles-via-

21. https://pubmed.ncbi.nlm.nih.gov/27467683/

22. https://www.researchgate.net/publication/299391569_Evaluation_of_Clinical_and_Antimicrobial_Effi

23. https://www.hindawi.com/journals/bca/2019/4649506/

24. https://www.intechopen.com/chapters/60717

25. https://pubmed.ncbi.nlm.nih.gov/29472649/

26. https://pubmed.ncbi.nlm.nih.gov/16350475/

27. https://pubmed.ncbi.nlm.nih.gov/24487610/

28. https://pubmed.ncbi.nlm.nih.gov/34496756/

29. https://downloads.hindawi.com/journals/tswj/2014/293019.pdf

30. https://pubmed.ncbi.nlm.nih.gov/29091818/

31. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6901576/

32. https://pubmed.ncbi.nlm.nih.gov/31839988/

33. https://www.nature.com/articles/s41405-020-0037-5

34. https://www.nature.com/articles/s41405-020-0037-5

35. https://www.nature.com/articles/s41598-021-81112-y

36. https://pubmed.ncbi.nlm.nih.gov/33683238/

37. https://www.sciencedirect.com/science/article/abs/pii/S1742706118304306?via%3Dihub

38. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8145068/

39. https://www.ncbi.nlm.nih.gov/books/NBK513314/

40. https://pubmed.ncbi.nlm.nih.gov/30031162/