The first adult trial on fluoride-free hydroxyapatite and what it found
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Time to read 6 min
Until recently, clinical evidence for hydroxyapatite toothpaste had been concentrated in two groups: children and orthodontic patients. Adults, the largest toothpaste-buying population in the world, had no dedicated randomised controlled trial to point to. A 2023 study published in Frontiers in Public Health by Paszynska, Pawinska, Enax, Meyer et al. changed that. [1]
The 18-month double-blinded RCT enrolled 194 adults aged 18–45 across two Polish university dental centres and directly compared a fluoride-free 10% hydroxyapatite toothpaste against a sodium fluoride toothpaste at 1,450 ppm — the standard high-strength concentration used in most premium adult toothpastes globally. Of the 194 enrolled, 189 were included in the intention-to-treat analysis and 171 completed the full per-protocol study. [1]
How the trial was designed
A key methodological strength: both toothpastes were formulated with identical bases, same abrasives, humectants, binders, surfactants, and flavouring. The only difference between them was the active ingredient: hydroxyapatite in the test group, sodium fluoride in the control.
This is a more rigorous design than many prior studies, which compared commercially available products with different formulations, making it difficult to isolate the active ingredient's effect. [1]
Participants brushed twice daily for three minutes using an electric toothbrush. No other fluoride- or hydroxyapatite-containing products, mouthwash, gels, fluoride supplements, were permitted during the trial.
Caries status was measured using the gold-standard DMFS index (Decayed, Missing, Filled Surfaces) at four time points, supplemented by DIAGNOcam near-infrared transillumination imaging for detecting subsurface lesions invisible to the naked eye. [1]
The primary result
he trial's primary endpoint was the percentage of subjects showing no increase in DMFS over 18 months. The result, as stated in the paper, was unambiguous: [1]
"No increase in DMFS index was observed in 89.3% of subjects of the hydroxyapatite group and 87.4% of the subjects of the fluoride group."
— Paszynska et al., Frontiers in Public Health, 2023
Non-inferiority was formally confirmed: the upper limit of the one-sided 95% confidence interval for the difference between groups was 6.84% — well below the pre-specified non-inferiority margin of 20%. [1] The authors note that assuming a margin of equivalence of ±20%, the results indicate not merely non-inferiority but equivalence of the two toothpastes.
A closer look at the mean DMFS change tells an even more interesting story. Over 18 months, the hydroxyapatite group showed a mean DMFS increase of just 0.02 effectively zero. The fluoride group showed a mean increase of 0.31. While the difference was not statistically significant enough to claim superiority, the hydroxyapatite group's DMFS increase was the lowest recorded when compared against published fluoride toothpaste trials going back decades. [1]
"Although not statistically significant in all three clinical trials, there was a tendency that the hydroxyapatite toothpastes were slightly more efficient than the corresponding fluoride control toothpastes."
— Paszynska et al., Frontiers in Public Health, 2023
What the secondary measures showed
DIAGNOcam imaging — which can detect lesions beneath the enamel surface that are invisible to clinical examination — confirmed the primary finding. No increase in subsurface caries lesion percentage was observed in 60.71% of the hydroxyapatite group versus 57.47% of the fluoride group, with the hydroxyapatite group again formally non-inferior. [1]
On plaque control (PCR index), both groups improved over the course of the study. The authors note that the hydroxyapatite group showed a tendency toward lower plaque scores across all time points — consistent with prior in situ research showing hydroxyapatite particles reduce initial bacterial colonisation on enamel surfaces. [1]
Safety: no adverse events
Across all 194 randomised subjects over 18 months, no serious adverse events were reported in either group. In nearly all recorded minor adverse events, causality with the toothpaste was rated as "unlikely" — 99.4% in the hydroxyapatite group, 99.0% in the fluoride group. No subject left the trial due to a caries-related event.[1]
Why this is the third piece of a growing picture
The authors explicitly position this trial as the third in a series of RCTs establishing the same finding across different age groups. The paper states directly that this is "the third clinical trial showing that fluoride-free hydroxyapatite toothpastes are non-inferior to fluoride toothpastes in caries prevention.."[1]
The authors' conclusion is direct: "hydroxyapatite serves as an efficient and safe alternative to fluoride in anticaries toothpastes for all age groups."[1] They also note hydroxyapatite's broader clinical evidence base — including published research on dentin hypersensitivity relief, periodontal health improvement, biofilm control, and whitening — as factors distinguishing it from fluoride, which offers more limited secondary benefits
One note on funding transparency
In the interest of full transparency: this study was partially funded by Dr. Kurt Wolff GmbH & Co. KG — the manufacturer of Karex, a commercial hydroxyapatite toothpaste whose formulation was comparable to the test toothpaste used. Three of the paper's authors are employees of that company.
The authors declare no conflict of interest beyond this, and the study was independently monitored, ethically approved, and registered on ClinicalTrials.gov (NCT04756557). Readers can weigh this context alongside the methodology and results.[1]
REFERENCES
https://pmc.ncbi.nlm.nih.gov/articles/PMC10393266/
[1] Paszynska E, Pawinska M, Enax J, Meyer F, Schulze zur Wiesche E, May TW, Amaechi BT, Limeback H, et al. "Caries-preventing effect of a hydroxyapatite-toothpaste in adults: a 18-month double-blinded randomized clinical trial." Frontiers in Public Health. 2023 Jul 18;11:1199728. doi: 10.3389/fpubh.2023.1199728. PMCID: PMC10393266.
Read on PubMed Central →Trial registered at ClinicalTrials.gov: NCT04756557. Ethics approval: Poznan University of Medical Sciences, No. 691/20, November 2020. Partial funding by Dr. Kurt Wolff GmbH & Co. KG; three authors are employees of that organisation.
This article is an editorial summary of publicly available peer-reviewed research. It does not constitute dental or medical advice, and makes no therapeutic claims about any specific product. The research summarised was conducted independently of Peg Paste. Individual results may vary. Always consult a qualified dental professional for personal oral health advice. Peg Paste Pty Ltd, Noosa Heads QLD Australia.
WHAT IS HYDROXYAPATITE?
Hydroxyapatite is a restorative mineral that occurs naturally in teeth and bones. Hydroxyapatite works to repair, remineralise and strengthen the tooth’s outer layer, acting as a buffer to help prevent mineral loss, tooth erosion, tooth sensitivity and plaque.
HOW DO PREBIOTICS SUPPORT ORAL HEALTH?
Prebiotics support oral health by promoting the growth of beneficial bacteria, which can help maintain a balanced environment in the mouth. It is important to maintain good oral hygiene so harmful bacteria does not take over potentially leading to bad breath, cavities and disease.
WHERE IS PEG PASTE MADE?
Peg Paste is made and manufactured in Australia.
DO YOU USE MICRO-HYDROXYAPATITE OR REGULAR HYDROXYAPATITE?
We use micro-hydroxyapatite in our toothpaste and ensure that it fully complies with current SCCS (Scientific Committee on Consumer Safety) and Australian oral care and cosmetic regulations. We are aware of the European Union’s upcoming ban on nano-materials in cosmetics starting November 2025. The reason for this ban is still unclear, but reports suggest potential risks if nano-hydroxyapatite is used in high concentrations or in sprayable products, where inhalation could be a concern. Since our toothpaste is not a spray and is formulated with concentrations that are within safe guidelines, we remain confident in its safety and effectiveness.
IS PEG PASTE SUITABLE FOR CHILDREN?
Absolutely. Prevention is key when it comes to oral health, so why not instil healthy habits early. Children’s toothpaste normally consists of a lower level or no fluoride because of the greater risk of potential fluoride toxicity. Given Peg Paste is a natural, fluoride-free formulation, it is safe for junior toothypegs. We recommend children use a pea size amount and brush under adult supervision.
I HAVE SENSITIVE HEALTH, IS THIS PRODUCT SUITABLE FOR ME?
Science shows that Hydroxyapatite helps ease tooth sensitivity by filling in microscopic pathways to the nerves in the teeth. With fewer pathways exposed, the less sensitivity and discomfort you should feel to touch, food and temperature. Remember to always consult your dental professional for oral health advice and before trying new products.
I SUFFER FROM DRY MOUTH, IS THIS PRODUCT SUITABLE FOR ME?
Peg Paste does not contain Sodium Lauryl Sulfate or SLS, a common ingredient that acts as a thickener in toothpaste products. SLS can have negative, degenerative effects that can contribute to, or worsen serious oral health issues such as dry mouth, mouth ulcers, mouth irritation and bad breath. Changing to an SLS free toothpaste can make a difference if you’re experiencing these symptoms. Remember to always consult your dentist or dental hygienist for oral health advice and before trying new products.
