Question

How is the position of the tongue affected by raising and lowering the mandible?

Answer 1

The normal rest position of tongue is at the top of the mouth, sitting about 1/2 inch behind the front teeth. The full tongue (including the back) should be pressing against the roof of the palate, lips should be sealed and upper and lower teeth must be slightly apart. The breathing pattern of an individual influences the position of the tongue.In a normal individual breathing occurs through the nose(Nasal breathing).

• Nasal breathing is the correct way of the air entering into the body. During nasal breathing tongue rests on the palate and the inward pressure applied by the cheek muscles from outside is balanced by the force of the tongue from inside outwards.In normal breathing air passes through nose. Tongue position - normal
• Mouth breathing- If any inflammation occurs to the tonsils or lymphoid tissues or adenoids in the nasal pathway, these become swollen. They develop obstruction for nasal breathing and slowly mouth will be the primary way of intake of air into the body. In order to breath through the mouth mandible comes down and the tongue comes off the palate and settles on lower teeth. Tongue position - lowered and confined to the space within the lower jaw (mandible).

In mouth breathing the pressure applied by the cheeks are unopposed by the tongue.This creates an imbalance of the system and thus making the upper jaw constricted. The "U" shaped arch will become "V" shaped in upper jaw. This also creates an incorrect swallowing function. Upon swallowing, the tongue thrust on the lateral tooth of lower jaw causing a lateral tongue thrust.A constantly open mouth causes the lower incisors to over erupt. The result is the malformation of the lower jaw known as bicuspid drop off.
The result of this deformation of the upper and lower arches is the presence of premature contacts upon closing, which shifts the lower jaw distally off of the physiological trajectory. The narrowing of the upper arch push the lower jaw back. This forces the TMJ condyle to shift distally while the TMJ disc moves forward. This causes clicking sound in TMJ while closing and opening the mouth. In addition the muscles associated with TMJ will be in hyper spasm causing a tension type headache.the incorrect position of the lower jaw can cause the parafunctional activity of the muscles such as clenching and grinding. Over time this leads to severely worn down teeth. As a result the teeth will become even shorter and the the lower jaw shifts distally and the vertical overbite decreases. In time joint degeneration occurs, the joint become deformed and ligaments of the joint become damaged. As a result the TMJ disc can be dislocated in front of the condyle with a limited mouth opening.
The distally shifted lower jaw and tongue position further restriction of airway. In order to open up the airway the neck moves forward and the head tilt backward. This results in neck,back and shoulder pain.