Fullness of the ears and subjective hearing loss can occur when there is dysfunction of the tensor veli palatini and medial pterygoid muscles. Both muscles are innervated by a branch of the mandibular nerve. (Trigeminal Connection). All muscles of the palate are supplied by the pharyngeal plexus except the tensor veli palatini which is supplied by a branch of the mandibular nerve.
Tensor Tympani innervated by the Trigeminal Nerve (feed back loop)
The tensor veli palatini and tensor tympani are innervated by segment of the trigeminal nerve and when deep somatic and visceral pain occurs from a primary pain source, i.e. the temporalis, masseter and pterygoid muscles, the effects spread to other divisions of the same neural segment. The effects relate to both the intensity and duration of primary pain.
If skeletal muscles are involved clinical dysfunction may be observed. Excitation patterns spread to other main divisions of the same segment. Secondary effects from primary trigeminal pain therefore would be expected to remain confined within the trigeminal distribution.
Patients with intermittent allergic edema of the eustachian tube reflexly initiate bruxism in order to open the orifices so that normal pressures on both sides of the ear drum are restored.
When the tubes are intermittently obstructed by allergic edema, reflex nocturnal bruxism occurs and reopens the eustacian tubes. Nocturnal bruxism often persists throughout adult life from allergy, habit, or malfunction of the eustachian tubes.
Dr. James F. Garry, DDS Perspective
Bruxism is a subconscious reaction to a malocclusion and/or Eustachian tube dysfunction. It is usually the result of hypertrophied lymphoid tissue blockage or partial blockage of the orifice of the Eustachian tube in children. When a child bruxes, the medial pterygoid muscle affects the function of the tensor veli palatini (TVPM) due to their approximation. Since the TVPM dilates the Eustachian tube, contraction opens the Eustachian tube equalizing middle and outer ear pressure. The TVPM descends vertically between the medial pterygoid plate and pterygoid muscle. Contraction and relaxation of the medial pterygoid muscle results in additional movement of the TVPM due to the approximation of both muscles. The Eustachian tube is often partially obstructed by hypertrophied adenoid tissue and the TVPM cannot open the Eustachian tube adequately. Contraction of the medial pterygoid muscle in bruxism assists the TVPM in partially opening the Eustachian tube to equalize middle and outer ear pressure.
Many dentists have contacted me over the years relating how their children stopped bruxing within 3 months following an adenotonsillectomy.