What’s so special about the CariFree Gel?

Recently there has been a lot of interest in nano-hydroxyapatite as a remineralizing ingredient in oral care products. We turned to CariFree CEO and founder, Dr. Kim Kutsch, a world-leading expert in dental caries disease and tooth remineralization science, for some insight. The following study packet addresses a few of the commonly asked questions and reviews the most current literature on the subject. Read on to learn more and hear what Dr. Kutsch has to say on this multi-faceted, complex topic.

With the rising popularity of nano-hydroxyapatite on the market, I’m often asked about its use with patients and what is most important to look for when recommending a product. Many believe percentage matters most, but in fact, the two most critical components for remineralization and safety are the size and shape of the nano-hydroxyapatite particles.

While older studies examined the results from 10% nano-hydroxyapatite, and one study concluded that it may be the best concentration for remineralization, a newer study found no significant difference between 2, 5 and 10% solutions.1,2 The most current literature indicates size and shape are most important, with 20 nm average particle size and spherical shape providing the best outcomes.3

In addition to questions about the effectiveness of n-HA toothpastes, questions regarding safety and quality have also been on the rise. The only nano-hydroxyapatite materials we are aware of that are deemed safe and suitable by the European Scientific Committee on Consumer Safety (SCCS) are manufactured by a European company, FLUIDINOVA, and branded nanoXIM. This has become the superior brand in the industry, and the only one CariFree has sourced and used in our formulations since our first tooth gels were created in 2012. Nano hydroxyapatite has been the foundation of our gels since the beginning. This means we follow the strictest efficacy and safety guidelines set forth by the governing bodies including the SCCS.

CariFree is proud to partner with FLUIDINOVA and we utilize a proprietary concentration of their nanoXIM combined with Sodium Fluoride to create the optimal remineralization ratio. We add fluoride because fluoride and nano-hydroxyapatite work synergistically together, creating fluorapatite which is even more acid-resistant than hydroxyapatite alone.4 This remineralization technique will protect teeth longer during pH drops and acid attacks.

The last significant component of our formulation is the alkaline pH (9), which allows our gels to create an oral environment designed for remineralization. Healthy teeth require a healthy biofilm, and a healthy biofilm requires a healthy mouth. Arguably, more important than the type of mineral being supplied is the shift in oral pH. Without elevating the pH first, remineralization may not take place at all. In a recent study, the CariFree PRO Gel 5000 toothpaste demonstrated effective pH buffering capabilities in dental plaque, maintaining a range crucial for enamel remineralization during a 20-minute sucrose challenge. This performance indicates the toothpaste’s potential to create an oral environment that favors remineralization and counters the acidogenic effects typically induced by sugar intake.5

At the end of the day, the goal is to get a product that works. I can confidently say and show you, without a doubt, that the CariFree gels are safe and effective. A recent 2022 study has shown the CariFree PRO Gel 5000 achieved a 63% surface microhardness recovery in just three days.6 This is particularly impressive when compared to a similar study where a high fluoride control toothpaste, also with 5000 ppm fluoride, achieved a 33.5% recovery, but over a longer period of 10 days.7

Remineralizing oral care products can be a hugely effective weapon in the battle against cavities, which we know from using fluoride in our practices for decades. The combination of fluoride and nano-hydroxyapatite is a great option that can further help us with improving remineralization for our patients.



V Kim Kutsch


  1. Huang, S. B., Gao, S. S., & Yu, H. Y. (2009). Effect of nano-hydroxyapatite concentration on remineralization of initial enamel lesion in vitro. Biomedical Materials, 4(3), 1-6. doi:10.1088/1748-6041/4/3/034104
  2. Haghgoo R, Rezvani MB, Salehi Zeinabadi M. Comparison of nano-hydroxyapatite and sodium fluoride mouthrinse for remineralization of incipient carious lesions. J Dent (Tehran). 2014 Jul;11(4):406-10. Epub 2014 Jul 31. PMID: 25584051; PMCID: PMC4283741.
  3. Imran E, Cooper PR, Ratnayake J, Ekambaram M, Mei ML. Potential Beneficial Effects of Hydroxyapatite Nanoparticles on Caries Lesions In Vitro-A Review of the Literature. Dent J (Basel). 2023 Feb 7;11(2):40. doi: 10.3390/dj11020040. PMID: 36826185; PMCID: PMC9955150.
  4. Chapter 7 – Caries and other reasons for restoring teeth, Editor(s): A. Damien Walmsley, Trevor F. Walsh, Philip J. Lumley, F. J. Trevor Burke, Adrian C.C. Shortall, Richard Hayes-Hall, Iain A. Pretty, Restorative Dentistry (Second Edition), Churchill Livingstone, 2007, Pages 57-72, ISBN 9780443102462, https://doi.org/10.1016/B978-0-443-10246-2.50010-1. (https://www.sciencedirect.com/science/article/pii/B9780443102462500101)
  5. G. Thomas, T. Badrock and L. Davies. (2023). In Vitro Test to Compare the Ability of a Toothpaste Formulation Versus a Negative Control to Buffer the pH of Dental Plaque During a Sucrose Challenge. Intertek Laboratory 150-LAB-PLQ-23-001.
  6. G. Thomas, T. Badrock & C. Thompson. (2022). An In Vitro Study to Evaluate the Ability of a Toothpaste Formulation to Repair and Protect Demineralised Enamel Samples. Intertek Laboratory 150-LAB-SMH-22-002.
  7. P. Frank Lippert and B. Karmjeet K. Gill, Carious lesion remineralizing potential of fluoride and calcium containing toothpastes, JADA, p. 7, 2019.


Our Nano-hydroxyapatite Products

PRO Gel 5000

Dentist Exclusive Product – A 1.1% prescription-strength fluoride, low abrasion tooth gel that combines proven anti-cavity benefits of fluoride, nano-hydroxyapatite and our unique, patented pH+ technology to neutralize acids.

Add to your cart here

Gel 1100 Anti-Cavity Toothpaste
CariFree toothpaste with nano hydroxyapatite

This low abrasion tooth gel combines proven anti-cavity benefits including .24% fluoride, nano-hydroxyapatite and our unique, patented pH+ technology to neutralize acids. We proudly use nanoXIM by FLUIDINOVA in our products, the only nano-hydroxyapatite globally recognized and approved for oral care by the European Scientific Committee on Consumer Safety.

Add to your cart here


Fluoride Free Gel

CariFree's flouride free toothpaste with nano hydroxyapatite.

A low abrasion, fluoride free tooth gel that combines nano-hydroxyapatite and our unique, patented pH+ technology to neutralize acids. We proudly use nanoXIM by FLUIDINOVA in our products, the only nano-hydroxyapatite globally recognized and approved for oral care by the European Scientific Committee on Consumer Safety.

Add to your cart here


Nano-hydroxyapatite FAQs

What is nano-hydroxyapatite toothpaste?

Toothpaste containing nano-hydroxyapatite is an excellent option for those looking to remineralize their teeth and protect against future cavities.

Is nano-hydroxyapatite toothpaste safe for pregnant women?

While nano-hydroxyapatite is recognized as safe for all users, it never hurts to check with your medical provider on any new products during pregnancy.

Is nano-hydroxyapatite safe for children?

Yes, nano-hydroxyapatite is safe for both children and adults.

How does nano-hydroxyapatite toothpaste work?

Nano-hydroxyapatite works by remineralizing—it replaces missing sections of minerals that have dissolved out of enamel by bonding directly to the tooth surfaces.

Is nano-hydroxyapatite good for sensitive teeth?

Yes, nano-hydroxyapatite has been shown to relieve sensitivity (source).

Does nano-hydroxyapatite rebuild enamel?

Yes, nano-hydroxyapatite has been shown to remineralize enamel (source).

Can I eat or drink right after using nano-hydroxyapatite?

For best results, we recommend waiting at least 30 minutes to give the ingredients time to work.

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