Disk Displacement Without Reduction

This occurs when the ligaments are stretched more and the disk slips too far out of position so that it can no longer “click” back into place. It then acts like a door-jam and blocks the normal movement of the joint. As the mouth opening is limited it is also called “locked jaw” even though typically a person can still open to two-finger widths. 

When the disk is positioned forward there is increased load onto the painful and compressible retrodiscal tissues which can lead to increased TMJ/ear pain, deviated mouth opening, bite changes and osteoarthritis. Acute jaw locking episodes can usually be unlocked using manual jaw manipulation and oral splints. If the locking is left untreated then the disk displacement becomes chronic as there are more permanent anatomic changes within the TMJ. 

Successful treatment will usually result in increased mouth opening, decreased pain and increased ability to eat normally. Typically the clicking will return and not go away. Treatment usually consists of medications, jaw exercises, manual jaw manipulation, oral appliance therapy and minimally invasive arthroscopy.

Diagram 1 – Locked Jaw