INJURY: A severe injury to the jaw can
result in a fractured jaw bone. If the force of a blow to the jaw
is transmitted to the TM joint it may cause bleeding or inflammation
in the joint. It may disrupt the disc causing locking and pain.
Other causes of TMD are not as clear.
GRINDING AND JAW CLECHING (Bruxing): Tooth grinding and jaw clenching are two very common oral habits which involve increased activity of the jaw muscles and may add stress to the TM joint. Many people grind and clench without symptoms. However, some people who clench or grind while sleeping may complain of sore jaw muscles upon waking in the morning.
STRESS: Thousands of years of evolution have prepared our bodies for only two responses to stress: fight or flight. In our society these options are not usually possible. We must deal with the reality of the situation which means internalizing our stress. Stress may increase muscle activity such as grinding or jaw clenching.
DEPRESSION: Depression magnifies our perception of pain. The brain chemicals involved in causing depression elevate our perception of pain. People who are suffering and are in pain for over six months may start to exhibit signs of depression.
JAW POSITION AND BITE: Where your jaw should be positioned and how your teeth fit together is a very controversial topic. Some people feel a bad bite causes TMD. Recent research suggests that there is very little relationship between the bite and developing TMD.