What happened when 610 children brushed with hydroxyapatite for two years
|
|
Time to read 5 min
A triple-blind RCT published in the International Dental Journal (2025) compared hydroxyapatite-fluoride toothpaste against standard fluoride toothpaste in pre-schoolers with active caries. Here's what the data showed.
Most toothpaste trials ask whether a product prevents new cavities from forming. This one asked a harder question: can hydroxyapatite-containing toothpaste actually arrest active caries lesions that already exist?
The trial, published in the International Dental Journal in April 2025, was designed and run by researchers from the University of Sassari (Italy), the University of Bern (Switzerland), and the University of Mainz (Germany). [1] It is triple-blind, randomised, and ran for 24 months across 64 public schools in Sardinia. 518 children completed it. The results are notable.
How the trial was designed
Four toothpastes were tested across two arms. The HAF (hydroxyapatite-fluoride) group used toothpastes containing fluoride-substituted hydroxyapatite and magnesium-, strontium-, carbonate-substituted hydroxyapatite in a chitosan matrix, at both 1,000 ppm and 1,450 ppm fluoride concentrations.
The control group used standard sodium monofluorophosphate (NaMFP) fluoride toothpaste at equivalent concentrations. All tubes were identical in shape and weight; the trial was blinded to children, parents, and examiners alike. [1]
What the data showed
At baseline, there was no statistically significant difference between the two groups in caries rates — in either enamel or dentine. [1] The groups were comparable. What happened over 24 months is where the results diverge.
~75%Active enamel lesions became inactive in HAF groupCocco et al., 2025 [1]P<.01Significance of enamel lesion reduction, HAF vs fluorideCocco et al., 2025 [1]518Children completed the full 24-month trialof 610 enrolled [1]
In primary teeth, the HAF group showed a statistically significant reduction in enamel lesions compared to the standard fluoride group (p < .01). [1] Of the 78 active enamel lesions in the HAF group at baseline, nearly three-quarters — 58 of 78 — were recorded as inactive at the two-year follow-up. The difference between the two groups in terms of lesions moving from active to inactive was statistically significant (p = .04). [1]
"Of the active lesions in the HAF group (n = 78) at baseline, nearly 3-quarters (n = 58) were inactive at the follow-up. The difference between the 2 groups (HAF vs NaMFP) in terms of change of status in primary dentition was statistically significant (P = .04)."
— Cocco et al., International Dental Journal, 2025
For partially active lesions at baseline in the HAF group, 13 of 40 became fully inactive by the two-year mark. [1] In the NaMFP (standard fluoride) group, only half of the lesions active at baseline achieved inactive status — a materially lower conversion rate.
On dentinal lesions, both groups showed similar rates of filled inactive lesions (p = .08), though the HAF group demonstrated a higher absolute number of inactivated lesions — a finding the authors describe as clinically meaningful even where statistical significance was not reached. [1]
Why this trial matters
The study's authors note that most existing fluoride literature demonstrates prevention of new caries — but evidence that fluoride toothpaste can actually reverse existing lesion activity is described as only "low to moderate." [1] This trial was explicitly designed to test whether hydroxyapatite-fluoride toothpaste could exceed that benchmark. Based on the results for enamel lesions in primary dentition, it did.
"The toothpaste containing biomimetic hydroxyapatite and fluoride may be better for children with active caries lesions in primary dentition."
— Cocco et al., International Dental Journal, 2025
On sensitivity: a double-blind RCT cited in the review found participants reported significantly lower dentinal hypersensitivity after two to four weeks of HAP use compared to fluoride controls. [1] Microscopy confirmed HAP particles physically occluding exposed dentinal tubules. A network meta-analysis (Hu et al., 2019) suggested nano-HAP toothpastes may be superior to multiple other desensitising toothpaste types including fluoride, potassium-containing, and strontium-containing formulas. [1]
On biofilm: studies show HAP reduces adhesion of pathogenic bacteria including Streptococcus mutans to enamel surfaces, while — importantly — not killing bacteria outright as chlorhexidine does. The review suggests this may have the advantage of "preserving the normally occurring oral flora" while still reducing pathogen colonisation. [1]
The mechanism: why HAP behaves differently
The study's authors explain that fluoride ions can interact with the hydroxyapatite structure to make it less soluble and more acid-resistant. Nano-sized particles of fluoridated hydroxyapatite are also able to penetrate enamel micropores and defects, facilitating remineralisation at a deeper level than surface fluoride alone. [1] The chitosan matrix in the HAF formulation tested may also assist in delivering mineral ions directly to the tooth surface.
Importantly, the presence of hydroxyapatite appears to facilitate remineralisation of initial enamel lesions to a greater extent than fluoride alone — the authors specifically hypothesise this as the mechanism driving the differential outcome between the two arms. [1]
REFERENCES
Reference
[1] Cocco F, Salerno C, Wierichs RJ, Wolf TG, Arghittu A, Cagetti MG, Campus G. "Hydroxyapatite-Fluoride Toothpastes on Caries Activity: A Triple-Blind Randomized Clinical Trial." International Dental Journal. 2025 Apr;75
(2):632–642. doi: 10.1016/j.identj.2024.09.037. Open access. Read the full paper →Trial registered at ClinicalTrials.gov: NCT04906291. Ethical approval: University of Sassari Ethics Committee, n° 217/2017. Funded by the University of Sassari and Curasept S.p.A. Authors declared no conflict of interest.
https://www.sciencedirect.com/science/article/pii/S0020653924016058
This article is an editorial summary of a publicly available peer-reviewed clinical trial. 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.
