Habits such as tooth and jaw clenching, tooth grinding (bruxism), lip biting,
fingernail biting, gum chewing, and abnormal posturing of the jaws are common
and have not been scientifically proven to result in TMD. Jaw habits are often
associated with TMD and may be contributing factors that perpetuate and
aggravate ongoing TMD symptoms.
Dental occlusion refers to the way the teeth fit together or the “bite”.
Historically, the dental profession has viewed malocclusion (abnormal bite) as a
primary causative factor in TMD. Recent valid research studies have shown that
malocclusion is usually not the cause of TMD except in a limited number of
cases. There may be situations when the way the teeth fit together may play a
contributing role in the initiation or progression of those limited
situations. Each case needs to be individually evaluated by the orofacial pain
doctor to determine a possible relationship.
Many patients with TMD report the onset of jaw dysfunction symptoms or
aggravation of preexisting TMD symptoms with increases in emotional stress or
psychological imbalance such as depression or anxiety. Scientific studies
indicate that many TMD patients experience levels of depression and anxiety that
are higher than the non-TMD population. To date, it has not been established
whether depression or anxiety is present prior to the onset of TMD and
contributes to its cause, or whether the chronic pain associated with TMD leads
to anxiety and depression. Many patients will increase their level of tooth
clenching and grinding when they experience emotional stress, psychological
imbalance or pain.
DISEASES OF THE TMJs
Several types of arthritis may develop in the TMJs like any other joint in
the body. It is common for osteoarthrosis to be present in the aging
population. Many other diseases, such as Parkinson’s disease, Myasthenia
Gravis, strokes, and Amyotrophic Lateral Sclerosis (Lou Gehrig’s disease), may
lead to excessive or uncontrolled jaw muscle activity.