Due to improper loading, the disc within the jaw joint can shift or collapse.
This typically occurs when opening the mouth, yawning, or chewing.
At this point, the head of the joint slips off the disc, and upon retraction, it returns to it. This produces a characteristic clicking or clacking sound.
Disc displacement can occur either forward or backward, toward the back of the joint. If the disc shifts backward, there is a high risk of deformation and complete loss of the ability to return to its proper position. In such cases, after a period of clicking, the patient notices that the sound suddenly disappears.
A crunching sound when opening the mouth, as well as its sudden disappearance, are warning signs. They indicate TMJ dysfunction and the onset of joint destruction.