A device for therapeutic includes a rigid screen (1) that is insertable behind the upper and lower lips of a user's mouth, the screen having a compound curvature and in a horizontal plane generally U-shaped profile, and in a vertical plane a convexo-concave cross-sectional profile that is gradually flattening from a central mid region towards the left and right ends (12, 13) thereof, the ends extended to reach at least past the premolar teeth on each side in the upper and lower jaws of the user when applied. A handle is attached to extend forward from a central mid region in the convex front face of the screen, the handle including a rigid stem (2) projecting from the front face at a neutral angle with respect to upper (5) and lower (6) halves of the screen (1), diverging from the stem in the vertical view.