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Does whiplash cause TMD in some
patients?
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TMD is a jaw area pain syndrome associated with bruxing,
clenching, jaw stiffness, occasionally joint alterations,
and associated MPS type radiating symptoms. Stress is often
an associated factor. TMD is not the result of trauma,
although due to the association with stress, trauma could
secondarily be an aggravator of TMD syndrome. TMD often has
associated neck pain that can mimic the effects of WAD. The
whiplash motion has not been shown to stress the jaw joint.
Treatment for TMD is aimed at stress reduction and the
elimination of bruxing or clenching.
The following material is based on a summary statement of
the Technology Assessment Conference on TMD held at the
National Institute of Health (USA) 1996, as well as related
studies on TMD and trauma exposure.
TMDs, formerly called temporomandibular joint syndrome
(TMJ), are associated with pain and discomfort in or around
the jaw area, with aches in the head-neck region. This may
be a very common disorder, but fortunately for most, it is
minor and temporary in nature, and only occasionally
requires treatment. It was previously thought that the
disorder was caused by some derangement in the jaw joint,
but current research does not support that proposition,
except in certain cases. Today, researchers generally agree
that TMD usually falls into one of three categories:
1. Myofascial pain:
The most common form of TMD. Presents as discomfort or pain
in or around the muscles that control jaw function and the
neck and shoulder muscles. The actual site of pathology is
not known. Current research indicates that jaw clenching,
teeth grinding, stress, anxiety or tension are closely
associated factors. Current treatments include relaxation
techniques and stress counseling. In these sufferers, most
of the general dysfunction is not related to an actual
physical or mechanical jaw problem per se, but rather to
psychological matters. Some people with myofascial pain fall
into the category of the somatoform pain disorder, where
psychogenic symptoms present as a physical disorder.
2. Internal derangement of the
joint: Refers to a dislocated jaw or displaced disc, or
injury to the condyle. The etiology, once thought to be
dental malalignment or malocclusion, has not been confirmed.
Treating this condition with dental devices to change the
bite has not been successful and can sometimes make the
problem worse. (Displaced discs also occur in about 24% to
38% of the normal asymptomatic population.) The disc
cartilage of the jaw is quite different from most disc
material elsewhere in the body. The jaw's cartilage is
fibrous (not hyaline cartilage), and has excellent healing
features. This would explain the remarkable remodeling and
healing seen in cases of severe direct joint trauma which
usually heal well without chronic problems or TMD.
3. Degenerative joint disease: Like any other
joint, the jaw can be involved in systemic arthritis, like
rheumatoid arthritis, or develop arthritis from significant
direct joint damage. In these cases, the treatment and
management is similar to any other arthritis. Occasionally,
direct severe trauma to the jaw joint that causes
significant damage to the joint can lead to osteoarthritis.
However, unlike post-traumatic arthritis in the peripheral
joints, post-traumatic jaw arthritis is very rare. When it
does exist, the symptoms are often minor in nature as
compared to other types of arthritis. This could be due to
the different characteristics of the fibrous cartilage
tissue.
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Figure 3.8
TMD and the MVA
How does the jaw move in a
rear-ender?
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Temporomandibular joint trauma in MVAs: It has
been shown that unless it sustains obvious direct trauma,
the jaw is not likely to be traumatized during motor vehicle
collisions (Howard 1991, 1995). Studies show that routine
jaw opening during eating would produce considerably more
stress upon the jaw joint than would the effects of a
whiplash type event. Epidemiologically, it has also been
shown that TMD occurs in people with WAD from MVA events
with the same prevalence as in the general population
(Heise, 1992) - causation effects have not been established.
Psycho-social factors and chronic temporomandibular
joint pain complaints: Recent studies and a
meta-analysis have shown that the major factors that lead to
so-called TMD chronic pain and dysfunction are closely
related to psycho-social factors, rather than physical
factors. This would account for the high rate of failure
when trying to treat chronic TMD disorders with physically
based therapy (Dworkin 1996, Marbach 1996, Turk 1996).
Causes of TMD
- Trauma: an uncommon cause, but can occur with
fractures and major disruption of the joint. Post
traumatic TMD is usually minor in severity
- Arthritis: as in rheumatoid arthritis, or other
systemic arthritic disorders
- Malocclusion: once thought to be a major cause, is no
longer considered a factor
- Jaw clicking: disc displacements per se are no longer
considered a factor in TMD
- Stress: this has now become the most common
associated finding of TMD. This may cause clenching and
grinding, or on the other hand, may be caused by the
clenching and grinding.
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