Tooth-Gritting and Upper Airway Widening: Mandibular Mechanics, Genioglossus Activation, and the Jaw-Airway Coupling as Displacement Management

We examine the functional coupling between jaw clenching (tooth-gritting) and upper airway patency through the displacement framework. Mandibular protrusion during clenching activates the genioglossus muscle via the jaw-tongue reflex, drawing the tongue forward and widening the velopharyngeal airway. This constitutes a DC4 path-cost tradeoff: the body accepts increased D(xi_dental) to reduce D(xi_airway).

Bruxism is reframed as an unconscious compensatory mechanism for sub-clinical upper airway resistance, and the athletic mouthguard performance effect is explained through the same coupling. Formal displacement variables and a coupling function J(theta_jaw) are defined.