(Temporomandibular Joint Disorders)
The set of TM disorders are complex and have a variety of underlying causes, not all of which are fully known and understood. It is widely accepted among dental professionals that TM disorders can usually be traced back to problems with the joint and the muscles involved in opening and closing of the jaw. However, while injury to the jaw area is often seen among TMJD cases, many times symptoms may be present without obvious cause.
According to the Academy of Orofacial Pain, the causes of TMD are unclear in large part due to the current theory that the condition is actually the result of several factors working together. Possible contributing factors and insult to the temporomandibular joint include:
- Injury to the jaw, including whiplash or over extension to the TMJs
- Teeth clenching and grinding
- Arthritric conditions
- Extented periods of mouth opening due to dental or intubation procedures
- Auto-immune diseases
- Growths with in the TMJ complex
- Sleep Bruxism
- Sleep Related Breathing Disorders (SRBDs)
The role of teeth grinding due to stress is also complicated by scientific research that shows many habitual tooth clenchers or teeth grinders never show symptoms of pain or discomfort of the jaw, while an individual with soreness in the jaw is less likely to grind or clenche their teeth due to the pain, and that any reported stress can be a result of the painful condition.
One early theory about a possible cause for TMD was orthodontics, however that belief has been dismissed with scientific evidence. There is current research underway into a possible link between TMD and hormones because women are more likely than men to experience TMJ pain and soreness. It has been discovered in recent years that the TM Joint has many estrogen receptors and thus the possible of assoication of more females suffer from TMDs
Disorders of the temporomandibular joint can be categorized in two main groups: myogenous TMD and arthrogenous TMDs. Myogenous refers to a condition affecting the muscles, usually brought on by overwork or tension in the jaw and supporting muscles. Arthrogenous refers to a joint related condition. involving either the hard or soft tissues or both, including disc dislocation and arthritis degeneration.
Part of the reason that there is still no concense agreement among healthcare professionals about the exact causes of TMDs is that TM disorders are complex, variable and are likely the result of numerous circumstances and conditions. Typically a patient will report multiple symptoms as part of a TMD condition and may have experienced more than one of the above listed co-factors.