Contracture of Jaw Muscles

By Dr. Vishaal Bhat on Monday 3 December 2007 with 0 comments



At the maximum mouth opening, the distance between incisal edges of the middle incisor teeth should be about 3.5 to 4 cm. This distance varies individually, although if a patient cannot open his/her mouth to the distance of at least 3 cm, it can be felt as an unpleasant functional restriction. A restricted ability of the lower jaw to move is designated as contracture which has several forms:

Inflammatory contracture has its origin at an inflammation around the mandibular elevators (mainly the m. pterygoideus medialis).

Muscular contracture appears by damage of the above mentioned muscle during mandibular anesthesia.

Arthrogenous contracture is caused by inflammations of the mandibular joint or by a chronic traumatization of the joint at occlusion defects.

Fibrous contracture is determined by fibrous changes at the mandibular joint area after traumas or burns.

Neurogenic contracture (trismus) appears at tetanus.

Therapy of restricted mouth opening should focus on elimination of underlying causes. In cases of an inflammation at the mandibular joint area, a temporary loose immobilization of jaws by a wire bonding has its place, besides the anti-inflammatory therapy. At other kinds of contractures, physical therapy (red Solux lamp), active and passive exercises and laser therapy are often used. Fibrous contractures need to be released surgically in some cases.

A total immobility of the mandibular joint is called ankylosis. It is a coalescence of the lower jaw articular process with the temporal bone. Its cause is usually the mandibular joint purulent inflammation associated with otitis or osteomyelitis during childhood, or an intra-articular fracture or contusion with the joint hematoma. It results at a significant restriction of mobility of the mandible. A diagnosis is confirmed by an X-ray examination at SchΓΌller’s projection, or a computer tomography examination. Ankylosis is treated surgically - arthro-plastic surgery - that includes cutting out the bone bridge followed by insertion of other material (fascia, cartilage) into the neo-formed glenoid.

Category: Oral Pathology Notes

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