It started as a NASA problem: what the research actually says about putting mineral back into enamel

This is a research piece rather than a story, so it is organised the boring way: what is settled, what is claimed, and what is not established. If you only read one section, read the last one.

1. Enamel is one specific mineral, not “calcium”

Tooth enamel is built overwhelmingly from hydroxyapatite — a crystalline calcium phosphate. This is not contested and it is not new; it is in every dental histology textbook.

It matters because of what follows. When enamel loses mineral, hydroxyapatite is the mineral it loses. Not calcium in the abstract, and not something a supplement can be a substitute for.

2. There is a measured line, and it is pH 5.5

The reference here is Colin Dawes’ 2003 paper in the Journal of the Canadian Dental Association, which asks the question directly in its title: What is the critical pH and why does a tooth dissolve in acid?

Below a pH of about 5.5, enamel begins giving up mineral to the surrounding fluid. Above it, mineral moves back in. The exact figure shifts a little with the calcium and phosphate already present in saliva, which is precisely the point of the paper — but the line exists, and it is chemistry rather than opinion.

3. It is a two-way exchange, running all day

Demineralisation and remineralisation are not two states a tooth is in. They are two directions of one continuous exchange, and both are happening every day of your life. A cavity is simply what it looks like when one direction has run more often than the other for long enough.

4. Frequency beats quantity, and it has been known since the 1950s

The Vipeholm study remains the reference point, and its finding is the one nobody repeats often enough: the number of separate occasions on which sugar reaches the teeth matters more than the total amount consumed.

A dessert eaten in one sitting opens one acid window. The same quantity spread across six moments in an afternoon opens six. Enamel does not count grams. It counts events.

Which is why an ordinary day — breakfast, coffee, something mid-morning, lunch, an afternoon coffee, dinner — is six acid windows, and why brushing twice covers the two moments furthest away from every one of them.

5. The part almost nobody in Europe knows: it began with NASA

This is the section that made us want to write the piece.

NASA studied hydroxyapatite because of a specific problem: in weightlessness, astronauts lose bone and tooth mineral. The agency was looking for a way to supply the body’s own hard-tissue material back to it. The Japanese company Sangi came across that work while trading patents, and took it in a dental direction.

Sangi launched its first hydroxyapatite toothpaste in Japan in 1980, and a second in 1985. For years both were sold as cosmetic whitening products, for an unglamorous reason: approval to make a medical claim takes a long time.

That approval came in 1993, when Japan’s Ministry of Health and Welfare recognised the company’s hydroxyapatite as an anti-caries agent. Three effects were acknowledged for that material:

1. Adsorption and removal of dental plaque.
2. Filling of microscopic defects on the tooth surface.
3. Remineralisation of sub-surface areas of mineral loss.

Read the second one again, because it is the whole reason a mineralised surface looks whiter. Pigment from coffee, tea and red wine lodges in microscopic pits. Fill the pits and there is less for the pigment to hold on to — and a smoother surface reflects light instead of scattering it.

So the whitening in this approach is not bleaching. Nothing has had its colour removed. The surface simply behaves differently.

6. The other half: the bacteria making the acid

Putting mineral back addresses what is being taken. It does not address what is taking it.

For that, the relevant literature is on xylitol and Streptococcus mutans. Xylitol resembles sugar closely enough that the bacteria driving decay take it up, and then cannot metabolise it. They fill up on something that returns them nothing.

Together, the two cover both directions of the exchange — which is the only sensible way to approach something that runs both ways all day.

7. What is not established — read this part

8. What we could measure ourselves

Everything above is other people’s work. The figures below are ours, and it is worth being precise about where each one comes from: the first was measured in a laboratory, the other three come from users over four weeks of ordinary use.

What is actually measured

Four numbers, and it is worth being precise about where each one comes from. The first was measured in a laboratory. The other three come from users over four weeks of ordinary use.

It has also been dermatologically tested — a patch test on twenty adults with sensitive skin, recorded as non-irritant and non-sensitising.

What that adds up to

1. Mineral, not just cleaning. Hydroxyapatite is what enamel is made of. It is the one thing a rinse that only removes can never give back.
2. Whiter without bleaching. The whitening is a smoother surface holding less stain, not peroxide stripping the outer layer.
3. Breath that comes from the tongue, not from mint. Fewer of the bacteria producing sulphur compounds, and no alcohol drying the mouth out two hours later.
4. Less tartar. Reported by nearly three in four over four weeks.
5. Three seconds, anywhere. No water, no sink, no spitting, no rinsing — which is the only way anything can be used at the moment the acid window is actually open.
6. Safe to swallow. Which is what makes the point above possible at all.

Dr. Toni Martinčević, DMDImplantologist · developed CariSpray

The formulation question was settled by the literature. The format question was not, and it turned out to be the harder one: a toothbrush cannot go to lunch with you, and a 500 ml rinse that has to be spat into a sink cannot either. Neither is present for six of the six windows.

So it had to work with no water, no rinsing and no sink — which in turn meant it had to be safe to swallow — and it had to take three seconds, because nothing slower gets done six times a day by anyone. Two or three sprays, aimed at teeth and tongue, held for five seconds. No fluoride, no alcohol. It is patent pending.

Skip, pause or cancel the delivery option at any time. No minimum, no fee. Because the whole idea rests on mineral arriving regularly rather than once, the people who get the most out of it are the ones who never run out.

If you are still not sure

Every order carries a 60-day money-back guarantee, counted from the day the order arrives. Keep the bottle — sealed, opened or empty, there is nothing to send back. Email with the order number and the purchase price and original shipping are refunded.

Sixty days is roughly three hundred and sixty acid windows. That is long enough to know.

Sources

1. Dawes C. What is the critical pH and why does a tooth dissolve in acid? J Can Dent Assoc 2003;69(11):722–4
2. NASA Spinoff — Semiconductor Research Leads to a Revolution in Dental Care, spinoff.nasa.gov
3. Sangi Co. Ltd — company history and “Medical Hydroxyapatite” approval, sangi-co.com
4. Gustafsson B.E. et al. — the Vipeholm dental caries study, on frequency of intake versus quantity
5. Milgrom P. et al. — xylitol and Streptococcus mutans, PubMed
6. CariSpray Clinical Prescribing Guide (EU), OralAdvance Labs — the four measured figures and the dermatological patch test