Search "hydroxyapatite vs fluoride" and you will find two confident camps and very little study design. One side says hydroxyapatite is a proven equal; the other says it is wellness marketing. Neither is quite right. The evidence base is real, it is better than most people outside dentistry realise, and it is narrower than the enthusiasts claim. This is what it actually shows as of 2026 — with the trial designs named, so you can check us.
Two different mechanisms, aiming at the same thing
Both ingredients are trying to shift the same balance. Every day, acid from bacterial plaque and from food and drink pulls mineral out of enamel. Saliva puts some of it back. Decay begins when the losing side wins for long enough.
Fluoride works largely by changing the chemistry of the repair. When mineral redeposits in the presence of fluoride, some of it forms fluorapatite, which is more resistant to acid than the original mineral. Fluoride also interferes with bacterial metabolism. It has decades of population-level data behind it, which is precisely why UK guidance recommends it.
Hydroxyapatite works by supplying the mineral itself. Enamel is approximately 96 to 97 per cent mineral by weight, and that mineral is hydroxyapatite. A hydroxyapatite toothpaste delivers small particles of the same material family directly to the tooth surface, where they can deposit into microscopic surface defects and act as a reservoir of calcium and phosphate. That is what "biomimetic" means in practice: same material, not a substitute chemistry.
Worth noting: these are not opposites. They are two routes to the same outcome, and there are combination products on the market that use both.
The evidence, study by study
The 18-month adult trial
The most substantial single piece of evidence is Paszynska and colleagues, published in Frontiers in Public Health in 2023. It was a double-blinded, randomised, active-controlled, parallel-group non-inferiority trial running for 18 months, with 189 adults in the intention-to-treat analysis and 171 completing per protocol. The comparator was a toothpaste containing 1,450 ppm sodium fluoride — that is standard-strength UK toothpaste, not a weakened control.
The primary endpoint was the proportion of participants with no increase in DMFS, the standard index counting decayed, missing and filled tooth surfaces. Result: 89.3 per cent of the hydroxyapatite group and 87.4 per cent of the fluoride group showed no increase, and the pre-defined non-inferiority margin was met.
What that means in plain English: over 18 months, in these adults, the hydroxyapatite toothpaste did not do worse than standard fluoride toothpaste on new decay. What it does not mean: that it did better, or that the result transfers automatically to every hydroxyapatite product on the shelf.
The one-year children's trial
Paszynska and colleagues also ran a one-year double-blinded randomised trial in children, published in Scientific Reports in 2021, looking at early childhood caries in primary teeth over 336 days. 207 children were in the intention-to-treat analysis and 177 finished per protocol. Lesion increase, measured as ICDAS code 1 or above, occurred in 72.7 per cent of the hydroxyapatite group and 74.2 per cent of the fluoride group. Again, non-inferior to the fluoride control.
Note the honest reading here: the majority of children in both groups developed new early lesions. Neither toothpaste is a force field. The finding is a comparison between two products, not evidence that toothpaste alone prevents childhood decay.
The sensitivity meta-analysis
For sensitive teeth, the strongest evidence is Limeback, Enax and Meyer's updated systematic review and meta-analysis, published in Biomimetics in 2023, pooling 44 human clinical trials. Hydroxyapatite products significantly reduced dentine hypersensitivity compared with placebo, and also compared with fluoride, in the pooled analysis. Against other established desensitising agents the difference was a non-significant tendency — in other words, comparable rather than clearly better.
This is the area where hydroxyapatite's case is strongest, and the mechanism is intuitive. Sensitivity typically comes from exposed dentine, whose microscopic tubules transmit stimuli to the nerve. Depositing mineral at the surface helps occlude those tubules.
The shorter remineralisation studies
There is also a body of shorter in-situ and laboratory work — participants wearing intra-oral appliances with enamel samples, mineral change measured by microradiography — comparing hydroxyapatite with lower-strength fluoride over days or weeks. Amaechi and colleagues published one such crossover study in BDJ Open in 2019. These are useful mechanistic evidence but they are not clinical outcome trials, and they should not be quoted as though they were.
What the evidence does not say
This is the part most articles skip, so we will be explicit.
- It does not say all hydroxyapatite equals all fluoride. Non-inferiority was demonstrated for specific formulations at specific concentrations against specific comparators. A 1% hydroxyapatite paste is not covered by a trial of a high-concentration one.
- It does not overturn population-level fluoride evidence. Fluoride's caries-prevention record spans decades and enormous populations. Two trials and a meta-analysis are meaningful; they are not a comparable body of evidence.
- It does not mean hydroxyapatite repairs teeth. Remineralisation of early, sub-surface mineral loss and deposition into microscopic defects is real. Regrowing lost tooth structure, closing an open cavity, mending a fracture or a chip is not. If you have a cavity, you need a dentist, not a tube.
- It does not settle the oral microbiome question. There is interest in how different actives affect the bacterial community in the mouth, but the human evidence is not yet strong enough for anyone to make confident claims either way.
- It does not mean fluoride is harmful. UK guidance recommends fluoride toothpaste, and nothing in this literature contradicts that. The research supports fluoride-free as a viable informed choice, not as a rescue from a danger.
How to read a claim you see online
Three questions will filter almost everything.
Was it in people, and for how long? A laboratory study on extracted teeth tells you about chemistry. A randomised trial tells you about mouths.
What was the comparator? Beating a placebo is a low bar. Matching 1,450 ppm fluoride over 18 months is a high one.
What concentration was tested, and does the product you are holding match it? This is the question that eliminates most marketing claims, because most products do not state a concentration at all.
What this means for the products we sell
We chose Biorepair because the concentrations are stated by the manufacturer and they are high. Biorepair lists Plus Total Protection at 200 mg/g (20%) microRepair® and Plus Sensitive Teeth at 240 mg/g (24%). microRepair® is Biorepair's patented zinc-substituted carbonate hydroxyapatite.
To be precise about the boundary: the trials described above tested other manufacturers' hydroxyapatite formulations, not Biorepair specifically. What they establish is that the ingredient class has genuine clinical support at meaningful concentrations. What Biorepair contributes is a stated, high concentration of that ingredient at £6.99. We think that combination is a sound basis for choosing, and we would rather explain the gap than paper over it.
Our care guide sets out the same evidence alongside the practical routine, if you want both in one place.
Choosing between them
If you are comfortable with fluoride and have a history of decay, fluoride toothpaste at 1,350 to 1,500 ppm remains the guidance-backed default and we will not argue with your dentist about it. If you prefer to avoid fluoride, hydroxyapatite at a meaningful concentration is the fluoride-free option with the best evidence behind it. If your main complaint is sensitivity, hydroxyapatite has a particularly good case regardless of which camp you started in.
Where to start
For everyday fluoride-free care, Biorepair Plus Total Protection at £6.99 is the sensible first tube. If cold air or cold drinks are your trigger, start with Biorepair Plus Sensitive Teeth at the higher listed concentration instead. Give either one six to eight weeks before you judge it, and keep your check-ups either way.
Sources
- Paszynska et al., Caries-preventing effect of a hydroxyapatite toothpaste in adults: an 18-month double-blinded randomized clinical trial, Frontiers in Public Health (2023)
- Paszynska et al., Impact of a toothpaste with microcrystalline hydroxyapatite on the occurrence of early childhood caries: a 1-year randomized clinical trial, Scientific Reports (2021)
- Limeback, Enax & Meyer, Clinical evidence of biomimetic hydroxyapatite in oral care products for reducing dentin hypersensitivity: an updated systematic review and meta-analysis, Biomimetics (2023)
- Amaechi et al., Comparative efficacy of a hydroxyapatite and a fluoride toothpaste for prevention and remineralization of dental caries, BDJ Open (2019)
- Xu et al., Advanced materials for enamel remineralization, Frontiers in Bioengineering and Biotechnology (2022)
- GOV.UK — Delivering better oral health: chapter 9, Fluoride
- Biorepair — microRepair® concentrations in Biorepair toothpastes