Explaining the Science
Peer-reviewed · Dentistry Journal, 2025
Sugar three times a day. Zero brushing. What protected the enamel?
A university lab built an artificial mouth designed to soften enamel, then tested NOBS tablets inside it. Here’s what happened in plain English, plus straight answers to the three biggest myths about nano-hydroxyapatite.
Broken down by Dr. Ilon Choai, NOBS co-founder
The setup: a worst-case mouth
The study ran at UT Health San Antonio, inside a lab system built to work like an artificial mouth.
120 blocks of enamel
Cut from cow teeth, the lab standard for enamel research, then split into four groups of 30.
A living layer of plaque
Each block got a coating of human saliva first. Then the two bacteria most tied to tooth decay were grown on top.
Sugar, three times a day
A 10% sugar rinse at every “meal,” day after day.
No toothbrush
Twice a day, each group got a 2-minute soak in its assigned product, then a rinse. Nothing else.
How they measured it
Acid softens enamel long before you’d ever see damage. So the team pressed a diamond-tipped tester into every block before and after the experiment, and calculated how much surface hardness each one lost.
Softer enamel means more mineral lost.
The results
Surface hardness lost, averaged per group of 30. Lower is better.
NOBS and the fluoride toothpaste landed in the same spot. Statistically, the half-point gap between them isn’t a real difference.
Both did significantly better than the placebo and no treatment.
Even the placebo helped a little. It contains calcium carbonate, which buffers acid. The gap between the placebo and NOBS is what the active formula added.
Why a mineral helps against acid
Enamel is mostly hydroxyapatite. NOBS uses a nano-sized form of that same mineral.
Research on nano-hydroxyapatite shows the particles cling to enamel and settle into plaque, where they work like a calcium and phosphate reserve. When acid shows up, that reserve gets released, which helps keep mineral in the tooth instead of pulling it out.
The tablet in the study is the complete NOBS formula, with xylitol and zinc citrate in there too. So this tested the formula you’d actually use, not one ingredient on its own.
The fine print, up front
It’s a lab study.
An artificial mouth controls things a real one can’t. Testing in people is the next step.
Brushing wasn’t simulated.
That makes it a stress test. It shows what the formula does on its own, against heavy plaque and constant sugar.
We paid for it.
A team at UT Health San Antonio designed it, ran it and published it. Per the paper, the funder had no role in the design, the data or the write-up.
Three myths about nano-hydroxyapatite
If you’ve spent five minutes researching it, you’ve run into at least one of these. Each gets its own answer, because each is a different question.
Myth 1
“It doesn’t actually work.”
Hydroxyapatite toothpaste has gone head-to-head with fluoride toothpaste in randomized, double-blind trials in people: children for one year, adults for 18 months, tracking new decay.
Both trials asked the same question: would hydroxyapatite fall short of fluoride? In both, it didn’t.
A 2021 review of the research found good evidence that hydroxyapatite works on its own, with no fluoride added.
Sources: Paszynska et al., Scientific Reports, 2021 · Paszynska et al., Frontiers in Public Health, 2023 · Limeback et al., Canadian Journal of Dental Hygiene, 2021
Myth 2
“Nano particles can’t be safe.”
Hydroxyapatite is the mineral your enamel and bones are made of. The nano form used in toothpaste has been reviewed several times over the past decade by the EU’s Scientific Committee on Consumer Safety, the scientists who advise European regulators on cosmetic safety.
Their latest opinion, finalized in 2025, concluded it’s safe in toothpaste at up to 29.5%. NOBS uses 5%.
The detail most people miss: that conclusion covers rod-shaped, uncoated particles of a specific size, and explicitly excludes needle-shaped ones. With nano materials, regulators look at shape, not just size.
Sources: SCCS final opinion on hydroxyapatite (nano), 2025 (summary) · SCCS/1648/22, 2023
Myth 3
“You need 10% for it to do anything.”
The number usually cited comes from a 2009 lab study, where remineralization climbed with concentration and leveled off around 10%.
But when researchers tested it in people’s mouths, the gap disappeared. In a 2011 randomized, double-blind study, 30 adults wore enamel samples in a mouth appliance for 28 days per toothpaste, rotating through 5% and 10% nano-hydroxyapatite (plus a fluoride control). The 5% and 10% toothpastes showed no significant difference in how much mineral the enamel regained.
5% is what NOBS uses, and it’s the exact formula tested in the study above.
Sources: Huang et al., Biomedical Materials, 2009 · Najibfard et al., Journal of Clinical Dentistry, 2011
Try the formula they tested.
NOBS Toothpaste Tablets, the exact product from the study. Online or at Target.
Source
Amaechi BT, Kanthaiah K, Farah R, Yang K, Obiefuna AC, Abdul-Azees PA, Vijayaraghavan M. Evaluation of the Efficacy of a Dentifrice Tablet to Prevent Dental Caries: A Microbial Study. Dentistry Journal. 2025;13(5):201.
A plain-English summary of published lab research, not personal advice.