Internal Derangements of the Temporomandibular Joint

woman grabbing her jaw in pain from internal derangements of the tmj

Internal Derangement is not a diagnosis but a category of conditions and it simply means abnormal function of the intra-articular structures. It is a non-specific term applied as a descriptive subdivision term for the group of non-arthritic TM joint disorders (e.g., DDWR, DDNR, open dislocation, full & partial open locking). The ICD-10 code for derangement of the TMJ is M26.61, with a modifier regarding the side (1 for right, 2 for left and 3 for bilateral). There is also a code for articular disc disorder M26.69, with same modifiers if is unilateral or bilateral.

Disc Displacement With Reduction (DDWR)

The evidence for disc displacement with reduction includes transient jaw movement interference, which might be accompanied by a joint noise (usually described as a click or pop) emanating from one or both joints.

The clinical history and examination evidence needed for this diagnosis includes:

  1. Repeatable clicking of the TMJ with an opening or closing (or both) motion of the jaw
  2. Opening should be normal in magnitude (>45mm)
  3. Opening pathway should end up on the midline when wide open

Note: There are some DDWR cases where the click causes a temporary shift off the midline until the click occurs then it returns to the midline.

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DDWR Episodic Locking

This disorder is essentially the same a DDNR, with the difference being that the jaw unlocks, usually by itself, and converts back to a DDWR condition. Many times patient will report that on waking they have a locked jaw (cannot open fully), but after a few minutes they can unlock it and open wide.

The clinical history and examination evidence needed for this diagnosis includes:

  1. Repeatable clicking of the TMJ with an opening or closing (or both) motion of the jaw
  2. Opening should be normal in magnitude (>45mm)
  3. Opening pathway should end up on the midline when wide open
  4. Report of a temporary loss of jaw motion that lasts from several minutes to several hours

Related Reading: TMJ Assessment: Jaw Range of Motion, Noise, and Tenderness

 

Disc Displacement No Reduction (DDNR)

In this disorder, the TMJ disk if fully displaced forward off the condyle and it does not return to a normal position during opening. Instead, it folds forward in front of the condyle and prevents full translation. The patient will be unable to fully open and may have a limitation of lateral motion. If the patient had previous joint noises, those stopped at the time of the movement restriction. It is possible that the opening will increase with stretching, but there is also the possibility of developing further problems such as arthritic changes.

The clinical history and examination evidence needed for this diagnosis includes:

  1. Recent onset loss of full jaw opening ability;
  2. Active opening equals an interincisal distance of <35mm;
  3. Patient will localize the reason for their limited opening to the affected joint;
  4. Prior history of clicking that has stopped in the now presumably locked joint.

 

Condyle Dislocation

A condyle dislocation is produced when the condyle has an excessive translation, and produces a wide-open movement. In order to return to the normal position, usually manipulation of the jaw is required.

The clinical history and examination evidence needed for this diagnosis includes:

  1. Patient reports they cannot close their mouth and it appears to be wide open
  2. This problem developed as a direct result of a medical or dental treatment procedure (e.g. anesthesia)
  3. The condyle in the locked joint is definitely forward of the articular eminence
  4. The condyle/joint capsule is very painful to palpation

 

Open Locking or Jamming

An open locking is present when the condyle becomes stuck or locked in a wide open, but the patient is able to reduce the locked jaw without assistance.

The clinical history and examination evidence needed for this diagnosis includes:

  1. The patient reports they cannot close their mouth and it appears to be wide open
  2. This problem developed spontaneously (yawning) or as a direct result of a medical or dental treatment procedure (e.g. anesthesia)
  3. The condyle in the locked joint is definitely forward of the articular eminence
  4. The condyle/joint capsule is very painful to palpation
  5. The difference between open locking and dislocation is that the former can be relocated by manual manipulation without sedation and the later requires sedation to manipulate

Related Reading: Closed Lock Mobilization: TMJ Exercises & Stretches

 

Partial Open Locking (Posterior Disc Displacement)

In this situation, the patient is more than half way closed and they cannot get their back teeth to come together. Sometimes this derangement is momentary and is self-reducing, other times it may require manual manipulation of the mandible.

The clinical history and examination evidence needed for this diagnosis includes:

  1. The patient complains of the inability to close their teeth fully together after opening
  2. The condyle is not anterior to the articular eminence
  3. The condyle/joint capsule is very painful to palpation
  4. With manipulation the disk (which is presumably posterior) shifts and then the teeth can come together

 

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The information and resources contained on this website are for informational purposes only and are not intended to assess, diagnose, or treat any medical and/or mental health disease or condition. The use of this website does not imply nor establish any type of provider-client relationship. Furthermore, the information obtained from this site should not be considered a substitute for a thorough medical and/or mental health evaluation by an appropriately credentialed and licensed professional. Commercial supporters are not involved in the content development or editorial process.

Posted: December 21, 2020
<a href="https://ostrowon.usc.edu/author/dr-glenn-clark/" target="_self">Dr. Glenn Clark</a>

Dr. Glenn Clark

Glenn Clark, DDS, MS is an expert on sleep apnea, orofacial pain and oral medicine, and Temporomandibular Joint Disorder (TMJ). Dr. Clark serves as the Director for the Advanced Program in Orofacial Pain and Oral Medicine at the Herman Ostrow School of Dentistry of USC.

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