Low forward rest posture of the tongue/Open mouth rest posture of the lips
Very light resting tongue pressures can influence tooth eruption and contribute to a malocclusion the most common being open bite and excessive overjet. Low forward rest posture of the tongue is a primary concern and needs to be addressed. The forward rest posture of the tongue is continuous and intermittent; with remaining forward disrupt the dental equilibrium by opening the freeway space. In being open for hours a differential dental eruption can occur resulting in malocclusion. This differential eruption and the force of the tongue resting forward is the primary mover of teeth rather than the actual tongue thrusting which is a common mistake.
A thorough evaluation is required to determine if there is a low forward rest posture of the tongue and if and what contributors there are for this incorrect rest posture. Some of the possible contributors I look for are as follows; thumb/finger sucking, tongue sucking, enlarged tonsils, high narrow arched palate, shortened frenum (tongue- tie), low tonicity of the muscles. The two main causes of this forward rest posture of the tongue most likely is, prolonged sucking habits and airway problems. Once a determination of contributors is established and or eliminated a regime of exercises would be the course of treatment.