There are a number of issues that can cause TMD. The most common of these is a subconscious habit of clenching or grinding of the teeth, usually during sleep or when under high amounts of stress. Patients with this cause of TMD may find that their symptoms vary over time depending on their level of stress, as stress has been found to intensify pain from TMD.
Other causes of TMJ problems include history of facial trauma and/or motor vehicle accidents, sleep disorders with clenching and grinding, obstructive sleep apnea, medication side-effects, medical disorders, and neural (nerve) disorders. Heart disease, sinus infection, spinal problems, improper nutrition, inadequate hydration (fluids), and stress are also contributing factors. Harmful habits are a major cause of TMJ pain and include bruxing, pipe-smoking, pencil-biting, and gum-chewing. Gum chewing in females, especially young women, has been shown to cause TM joint popping, clicking, and pain. The repeated chewing trauma causes internal derangement of the joint; the inner parts of the joint do not work together in harmony. In many women, continued gum chewing results in permanent joint damage, improper function, and future TMJ problems. Gum-chewing is harmful to the joints and should be avoided.
Oral habits such as clenching the teeth or grinding the teeth (bruxism) can cause TMJ pain. These habits can tire the muscles and cause them to go into spasm. The spasm causes pain which, in turn, causes more spasm. The end result of this spasm-pain-spasm cycle may eventually be a TMJ Disorder. Problems in the way the teeth fit together, or bite, can initiate TMJ Disorders. Improperly aligned teeth can sometimes place the chewing muscles under stress and cause them to go into spasm, thus setting off the harmful cycle described earlier.
Paula is under a great deal of pressure from work. She develops a habit of grinding her teeth while sleeping. This causes muscle spasm and, eventually, pain and tenderness in her jaw muscles. Because of these problems, a slight change in the position of Paula’s jaw occurs, and her teeth no longer fit together correctly. She develops a new chewing pattern, and this increases the muscle spasm.
Ever since he was a boy, David, has had teeth that do not fit together correctly when his mouth is closed. This never seemed to be much of a problem for him, but now his bad bite triggers tooth clenching and causes his chewing muscles to function incorrectly. Muscle spasm occurs, and pain limits the normal range of David’s jaw movements. As a result, David’s chewing pattern changes, and this contributes to his TMJ symptoms.