How many acid windows do you open in a day?

Seven questions. Most people guess three and score nine. The number matters more than anything else you do for your teeth — here is why, and here is yours.

An acid window is what opens every time something that is not plain water goes into your mouth. The pH at the tooth surface falls below the line where enamel starts giving up mineral, stays there about fifteen minutes, and takes roughly forty minutes in total to come back. One window a day is nothing. Nine is a different mouth entirely.

Answer honestly, for a normal working day, not your best day.

Nothing is sent anywhere. The scoring runs in your browser and stops when you close the page.

What your score is actually counting

It is not counting sugar, and it is not counting how well you brush. It is counting separate occasions, plus the two habits that stretch a single occasion into a long one: sipping slowly, and eating or drinking after the last brush of the day.

The reason occasions matter more than quantity is that a single window very nearly closes itself. Saliva raises the pH back over the line and carries calcium and phosphate back into the surface, and about forty minutes later the tooth is roughly where it started. Two people can eat the same food by weight and end up in completely different places, because one of them ate it in three sittings and the other in nine.

Now mark your brushings on that day. One before the first window, one after the last. Two points at the far ends of a line with every window that matters sitting in the middle, untouched by either.

That gap is fourteen hours long for most people, and nothing designed for a bathroom sink reaches into it.

The three moves that lower any score

What that last one means in practice

Two or three sprays across teeth and tongue, held about five seconds, then swallowed. No water, no sink, no spitting, about three seconds. It carries hydroxyapatite — the crystal enamel is made of, which is exactly what acid removes — in a particle small enough to settle into the pits a window opens. And xylitol, which the bacteria responsible for most decay take up as though it were sugar and then cannot metabolise.

It replaces nothing. Brush morning and night as you already do. This is for the eight moments in between.

What it costs

On the three-bottle delivery it works out at €18.13 a bottle, and a bottle lasts about a month. Sold on the official site only — it is not in shops or pharmacies.

Every order carries a 60-day money-back guarantee from the day it arrives. Keep the bottle — sealed, opened or empty, there is nothing to send back.