Caused by disruption of the ligaments that attach the articulating disk to the condyle of the mandible and the subsequent pull of the specific muscles of the joint such as the lateral pterygoid muscles. Three major causes include structural weakness, blunt facial trauma and mandibular hyperextension. (Hyperextension may be caused as a result of prolonged dental and surgical procedures that require intubation or subluxation [dislocation]of the joint.)
There are four common types of disc displacement categories:
- Type I has a non-painful click during opening or closing movements of the jaw
- Type II is similar in nature to Type I but has pain associated with it but it does not lock
- Type III includes the clicking sounds, pain and a history of locking.
- Type IV manifests with no click but has associated pain and a lockjaw.
Pain increased by function; clicking on opening, or opening limited to under 25 mm with no click; positive imaging (X-ray or MRI) findings; patient history of trauma; and usually only on one side.
- Type I: none, or flat-plane splint
- Type II: none, NSAIDs, or flat-plane splint
- Type III: NSAIDs and splint, surgical disc repair, or physical therapy
- Type IV: NSAIDs and arthrocentesis (a clinical procedure using a syringe to collect fluid from a synovial joint capsule), arthroscopy (a procedure used for diagnosing and treating joint problems, which involves inserting tube containing a fiber optic video camera into the joint), or arthrotomy (creating and opening in the joint to allow drainage of the joint)
Good with regular pharmacological management, behavioral therapy, and aggressive postoperative physical therapy, including home exercises, such as stretching and passive up, down, and rotational movement.