Figure 2.16 MRI scan showing disc displacement without reduction in the left TMJ. The disc (arrow) is located anteriorly to the condyle head, both in the closed (a) and open (b) mouth positions.
I. Diagnosis/Diagnoses
DC/TMD
- Disc displacement without reduction without limited mouth opening in left TMJ.
J. Case Assessment
- Patient has no pain, no occlusal changes, and acceptable mandibular movement capacity. The movement capacity may, however, be less than it was before the permanent disc displacement occurred but must be considered as acceptable.
- The patient may be worried about what has happened and what to expect in the future.
K. Evidence-based Treatment Plan including Aims
- Counselling and patient information.
- No other treatment needed.
L. Prognosis and Discussion
- Good short- and long-term prognosis due to no complicating factors in the patient’s medical history or psychosocial history, and the patient is young.
Background Information
- DC/TMD defines disc displacement without reduction without limited mouth opening as “an intraarticular biomechanical disorder involving the condyle–disc complex. In the closed mouth position the disc is located in an anterior (and/or medial or lateral) position relative to the condylar head, and the disc does not reduce with opening of the mouth. This disorder is not associated with current limited mouth opening.”
- Based on studies employing MRI, the prevalence of disc displacement without reduction is estimated to be 7–10%.
- Treatment seeking is usually associated with arthralgia, if present, secondary to disc displacement without reduction without limited mouth opening.
(Sandler et al., 1998; Naeije et al., 2013; Schiffman et al., 2014)
Diagnostic Criteria
DC/TMD criteria for Disc displacement without reduction without limited opening (Schiffman et al., 2014). Without imaging: sensitivity 0.54, specificity 0.79.
An intracapsular biomechanical disorder involving the condyle–disc complex. In the closed mouth position the disc is in an anterior position relative to the condylar head, and the disc does not reduce with opening of the mouth. Medial and lateral displacement of the disc may also be present. This disorder is associated with persistent limited mandibular opening that does not resolve with the clinician or patient performing a specific manipulative maneuver. This is also referred to as “closed lock.” Presence of TMJ noise (e.g., click with full opening) does not exclude this diagnosis.
History. Positive for both of the following:
- 1. Jaw locked or caught so that the mouth would not open all the way.
AND
- 2. Limitation in jaw opening severe enough to limit jaw opening and interfere with ability to eat.
Examination. Positive for the following:
- 1. Maximum assisted opening (passive stretch) including vertical incisal overlap ≥40 mm. (Maximum assisted opening of ≥40 mm is determined clinically.)
Imaging. When this diagnosis needs to be confirmed, TMJ MRI criteria are positive for both of the following:
- 1. In the maximum intercuspal position, the posterior band of the disc is located anterior to the 11:30 position and the intermediate zone of the disc is anterior to the condylar head.
AND
- 2. On full opening, the intermediate zone of the disc is located anterior to the condylar head.
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