What is TMD?

Trauma to the facial structures can lead to functional disturbances to the masticatory system. Trauma seems to have a greater impact on intracapsular disorders rather than muscular disorders. A direct blow to the face, MVA, is referred to as macro trauma, where as bruxism, clenching (small forces) applied over a long period is referred to as micro trauma.

The emotional centers of the brain influence muscle activity in many ways, one of which is the autonomic nervous system (ANS) that will increase muscle activity. Prolonged chronic exposure to emotional stress unregulates the autonomic nervous system, which may compromise the individual’s ability to adapt and to fight diseases.

Deep pain input can centrally excite the brainstem, producing muscle-protecting contractions. This is a normal, healthy manner in which the body responds to injury. A limited mouth opening often results in injury to the Masticatory System. One also should not eliminate cervical pain conduction for being responsible for facial pain and limited mouth opening.

Parafunctional (non functional) activity of the masticatory muscles include clenching, grinding of the teeth (bruxism). These activities may occur during the day (diurnal) or at night (nocturnal) or both. Some muscle hyperactivity may not even involve tooth contact or jaw movement, but may merely represent an increase in the static contraction of the muscle.

The etiology of TMD is not simple but multi factorial. Not all patients seeking care are biologically the same. Each patient has a biological system that can tolerate a certain degree of variation from ideal. The human muscular skeletal system is adaptable and can therefore tolerate considerable variation without showing signs of pathology or dysfunction. Once factors exceed the patients adaptability treatment is required. At times the patients adaptability is reduced, thus less significant etiologic factors become more influential. Problems then become more chronic and we start to see more changes in the central nervous system (CNS) which relates to central sensitization.