Demo 1 · Where a tooth comes to rest

A tooth sits where the chronic soft-tissue pressures on it balance. From the inside, the tongue pushes outward; from the outside, the lips and cheeks push inward. Set the two forces and watch the tooth tip toward the weaker side. When they are equal the tooth holds its position — the equilibrium the theory names. Magnitude alone does not move a tooth here; it is a lasting imbalance that does.

tongue 5lip 5net balanced
Net force is zero — in equilibrium — the tooth holds its position. With the forces matched the tooth is stable; this balanced state is what every arrangement of teeth settles into.

Demo 2 · Time, not force, moves a tooth

Bone remodels in response to how long a force acts each day, not how hard it peaks. The clinical threshold is about six hours — 360 minutes. Try the two presets: a forceful but brief swallow thrust and a gentle but all-day resting posture. Then drag the force as high as you like and watch the verdict ignore it — only crossing the duration line turns the bar red.

0180360540720daily duration of the force (minutes)threshold 360 min17 min
The force acts 17 min/day (0.05× the threshold) at magnitude 8. Verdict: the tooth does not move. No matter how high you push the force, under 360 minutes a day it cannot displace the tooth — the swallow thrust's 16.7 minutes is far too brief.

Demo 3 · Unlearning an abnormal posture

Myofunctional therapy treats a tongue habit the way habit reversal treats any habit: a correct rest posture, practised deliberately at each cue, converts a would-be reinforced repetition into a non-reinforced one, so the old posture’s automaticity decays, A(m) = A0 e−d m. Noticing the habit helps a little; the full program — awareness, a competing posture, and rehearsal until the new pattern is automatic — is fastest (Azrin & Nunn, 1973).

10% of baseline0%50%100%020406080cues met with the correct posture (m)
no therapyawareness onlyfull myofunctional therapy
Under full myofunctional therapy, the decay rate is d = 0.055. From an entrenched baseline of 0.95, the old posture’s automaticity after 24 corrected cues is 0.254 (25%). Reaching 10% of baseline takes about 41 such cues. Replacing the posture at every cue gives the steepest decline, which is why OMT works best as a structured, rehearsed program.