With decades of experience in clinical dentistry, Dr. Burhenne is passionate about broadening our understanding of the biology of our teeth and gums, rather than just treating problems as they arise. In this first part, he shares the story behind Ask the Dentist, what inspired his interest in nano-hydroxyapatite and how this ingredient is gaining attention in oral care, including insights on its safety, effectiveness, and benefits.
For those who may not know you yet, can you tell us a bit about Ask The Dentist and what inspired you to start this project?
“Ask the Dentist began as an attempt to bridge a gap I kept seeing in clinical dentistry: patients were being treated for dental disease, but very little attention was being paid to why those diseases were happening in the first place.
For most of modern dentistry, the dominant model has been procedural and repair-focused. Cavities get filled, gums get cleaned, teeth get extracted or replaced. Those interventions are often necessary, but they tend to address the end stage of disease, not the biological processes that caused it. Early in my career I became increasingly interested in the underlying biology of the mouth—especially the oral microbiome, airway health, nutrition, and the relationship between oral and systemic health.
Ask the Dentist grew out of that curiosity. I wanted to create a platform where people could understand the mouth not as a collection of isolated teeth, but as a living ecosystem connected to the rest of the body. The oral microbiome, for example, is one of the most complex microbial communities in the human body, and its balance affects everything from cavities and gum disease to cardiovascular health, metabolic disease, and even pregnancy outcomes.
Another motivation was communication. Dentistry is full of excellent science, but much of it never reaches patients in a clear, practical way. I felt there was an opportunity to translate emerging research—on things like remineralization, breathing and facial development, nitric oxide production in the mouth, and microbiome-supportive care—into information people could actually use in their daily lives.
So Ask the Dentist became a place to explore those ideas. It combines clinical dentistry, evolutionary biology, microbiology, and preventive medicine, with the goal of helping people understand how oral health fits into the larger picture of whole-body health.
At its core, the project is about shifting the paradigm: moving from a model that simply treats dental disease to one that understands and supports the biology of the mouth so disease is less likely to occur in the first place.”
What originally sparked your interest in nano-hydroxyapatite?
“My interest in nano-hydroxyapatite really started with a long-standing curiosity about alternatives to fluoride. Even before I became a dentist—going back to my early teens and then again in my late twenties—I already had a fairly clear perspective on fluoride. I understood its role in dentistry, especially the evidence showing that topical fluoride can strengthen enamel, and that was something I didn’t question in dental school. But I was always uneasy about the ingestion of fluoride, and that kept me thinking about whether there might be another way to support stronger teeth. So I was essentially always looking for a more biologically intuitive approach to remineralization.
When I first encountered the early research on hydroxyapatite—both micro- and nano-sized forms—I immediately went down that rabbit hole. The concept just made sense. Enamel itself is made primarily of hydroxyapatite crystals, so using a biomimetic material identical to the mineral structure of the tooth felt like a very logical approach.
What fascinated me was that hydroxyapatite is stable in saliva, biocompatible, and readily available to interact with demineralized enamel surfaces. Instead of relying on a chemical reaction to make enamel more acid-resistant, you’re essentially supplying the same mineral building blocks that enamel is already made of.
That biomimetic idea—supporting the tooth with the very material it’s built from—is what really pulled me into the science of nano-hydroxyapatite and kept me exploring it further.”
At what point did you realize this ingredient could change the future of oral care?
“Honestly, it was immediate. The moment I started reading the early research, it was obvious that nano-hydroxyapatite had the potential to change oral care.
What struck me first was the biomimetic nature of the material. Enamel is made almost entirely of hydroxyapatite crystals, so the idea of using the same mineral that teeth are built from just made intuitive sense. Instead of trying to chemically modify enamel the way fluoride does, you’re actually supplying the building blocks of the tooth itself.
Then I started looking more closely at the early studies, and they were surprisingly promising. In some cases, nano-hydroxyapatite didn’t just remineralize early lesions—it produced deeper remineralization than topical fluoride, meaning the mineral repair extended further into the lesion rather than remaining mostly on the surface. Some studies also showed that it created a smoother, more uniform enamel surface, compared with the more irregular surface sometimes seen after fluoride-driven remineralization.
Another important factor was its history of use in Japan, where hydroxyapatite had already been used in oral care for decades after the technology originally emerged from materials research developed during the early space program era. And because hydroxyapatite is already a natural component of tooth structure, its biocompatibility made a lot of sense.
When you put all of that together—the biomimetic chemistry, the early remineralization data, and the fact that there really wasn’t anything else approaching teeth in such a natural way—it felt like a very elegant solution to a longstanding problem in dentistry. Compared to ingredients like calcium carbonate abrasives or metal-based fluorides like stannous fluoride, hydroxyapatite simply seemed like a much more biologically logical approach.
So for me, there really wasn’t a long period of skepticism. Once I understood the science, it was immediately exciting.”
How does it compare to fluoride?
“When you compare nano-hydroxyapatite to fluoride from a topical standpoint, the research shows that it performs very well—and in some studies equally well or even better in terms of remineralizing early enamel lesions.
Topical Fluoride has a long clinical history and clearly works when applied topically. Its primary mechanism is chemical: fluoride ions interact with enamel to form a more acid-resistant mineral phase and help drive calcium and phosphate back into demineralized enamel. That process can slow or reverse early decay, which is why fluoride toothpastes and varnishes have been widely used in dentistry.
Hydroxyapatite works very differently. Instead of chemically modifying enamel, it provides the same mineral that teeth are naturally made of. Because enamel is largely composed of hydroxyapatite crystals, the particles in nano-hydroxyapatite toothpaste can integrate with microscopic defects in the enamel surface and supply calcium and phosphate directly where they are needed.
One of the interesting differences seen in some laboratory and clinical studies is the pattern of remineralization. Fluoride often produces a relatively mineralized outer layer on a lesion, while hydroxyapatite can contribute to deeper mineral deposition within the lesion body. In some comparisons, this leads to a smoother and more uniform enamel surface after remineralization.
Another practical advantage is how hydroxyapatite behaves in the oral environment. It is stable in saliva and disperses well in toothpaste formulations, making the mineral building blocks readily available during brushing and in the saliva afterward—exactly where remineralization occurs.
So the key point is that hydroxyapatite isn’t simply “more of the same” as fluoride. It represents a different, biomimetic approach. Instead of altering enamel chemistry to resist acid, it helps rebuild and reinforce enamel using the same mineral structure the tooth already contains.
And of course, whether fluoride is applied topically or ingested, we also have to consider the potential neurological risks associated with fluoride exposure—particularly for developing brains—which is one of the reasons nano-hydroxyapatite is so compelling as a modern alternative.”
What does the current science say about nano-hydroxyapatite’s safety and effectiveness?
"Nano-hydroxyapatite is an exciting development in oral care because it’s a biomimetic material—essentially the same mineral our teeth are made of. Enamel itself is about 96% hydroxyapatite, so using nano-hydroxyapatite in toothpaste is a very intuitive strategy: you’re helping replace lost mineral with particles that closely resemble the natural structure of enamel.
Recently, the European Commission’s Scientific Committee on Consumer Safety (SCCS) reviewed nano-hydroxyapatite and concluded it can be considered safe for use in oral cosmetic products when produced within specific particle size, shape, and concentration limits. That conclusion didn’t happen overnight; the SCCS has been examining nano-hydroxyapatite since 2013, requesting detailed toxicology, particle characterization, and exposure data before ultimately determining that materials meeting those specifications are safe.
FLUIDINOVA’s nano-hydroxyapatite is notable because it matches the material profile evaluated in that regulatory dossier, meaning it clearly fits within that safety framework. Beyond regulatory science, there is also a long real-world track record. Hydroxyapatite toothpastes have been used in Japan since the late 1970s, and millions of people have used them for decades without any signal of systemic harm. In my own dental practice and personal experience, the effect on tooth sensitivity has been particularly striking. I’ve prescribed 5000-ppm fluoride toothpastes for years, and while they can help, they rarely eliminate sensitivity completely. In my own case, if I stop using my nano-hydroxyapatite toothpaste—around 3–3.1% concentration—for just two or three days, the sensitivity tends to return. But when I use that same toothpaste once or twice a day, the sensitivity disappears again, which reflects what we understand about how hydroxyapatite works: the particles can help rebuild mineral density and physically occlude the microscopic dentin tubules that trigger sensitivity.
From a biological standpoint it’s a very elegant approach—restoring lost enamel mineral with enamel-like mineral—and at the very least, many patients appreciate that it avoids a concern some people have with fluoride, namely that fluoride can be swallowed or absorbed systemically. And finally, the word “nano” itself shouldn’t be alarming—it simply describes the size of a particle. What matters is what the particle actually is; when the substance is biomimetic, biocompatible, and something the body can naturally handle—like rod-shaped nano-hydroxyapatite—the concept of “nano” shouldn’t be viewed as a risk but as a tool that allows us to work at the same scale as the mineral structure of our teeth."
If you are interested in following Dr. Mark Burhenne work, you can visit his website at askthedentist.com.
Part 2 of the interview to be released on March 20th - World Oral Health Day.
