Smile Age, explained

What it is

Smile Age is a visual, appearance-based index. It combines your five scan dimensions with a five-question questionnaire, produces a combined score out of 100, and expresses the result as an age offset from your real age.

How the number is built

1. The questionnaire (worth 50). Five short questions — missing teeth and whether they've been replaced, smoking or vaping, whether you've been told you need a deep clean, and whether your gums bleed when you floss. Each carries a deduction; the fewer deductions, the closer to the full 50.
2. The scan (worth 100, halved). A weighted blend of your five dimensions, leaning hardest on cleanliness and gum appearance, then brightness, freshness and tongue. This contributes up to 50.
3. The combined score. Questionnaire plus half the scan, out of 100.
4. The age offset. The combined score maps to an offset band — a score in the high nineties reads about ten years younger, the mid-sixties to mid-seventies reads right on your age, and below the mid-fifties reads several years older.
5. Your Smile Age. Your real age plus that offset.

The app shows every one of those steps. That's deliberate: a number you can't take apart is a number you're being asked to take on faith.

Why an age instead of a score

Scores out of 100 have a calibration problem. Is 73 good? Against what? People have no intuition for it, so they either ignore it or invent a meaning for it.

Ages come pre-calibrated. Everyone knows what their own age is and immediately knows whether the answer is welcome. It gives the number a direction and a stake without needing a benchmark.

The limits — stated plainly

• It reads appearance only. It knows nothing about bone, nerves, roots, decay, or anything below a visible surface.
• It is not comparable between people. Two people with identical Smile Ages have nothing meaningful in common.
• It is sensitive to the questionnaire. Answering differently changes the number substantially, which is a feature — those factors matter — but it means the score is partly self-reported.
• It is not validated against any clinical outcome and makes no claim to be.
• A number that reads "older" is not a warning. It is an appearance reading, and the only sensible response is to look at which dimension pulled it down.

If ToothPal ever presents Smile Age without the words "visual, appearance-based" nearby, that's a bug.

Using it well

Re-test it every four to six weeks, not weekly — the underlying dimensions need time to actually move, and re-testing too often turns a trend into noise.

Treat the breakdown as the real output. The age is the headline; the questionnaire-versus-scan split tells you whether your number is being held down by things you can change this month or by history you can't.

Questions