Treating TMD, temporomandibular dysfunction.
Few areas of dentistry are as confusing as that for the treatment
of TMD, which can be debilitating for
many people. Currently hard splints are
in vogue but having worked or lectured in
all continents around the world, I have
continued to be amazed at the
differences between methods and
approaches to this problem. Some of them
must be wrong. What possibly can be
agreed on is that much of the problem
stems from the difference between the
positions of the jaw A) when the teeth
are in their biting position and B)
when the joints in its balanced position,
usually referred to as centric position.
Dentist and orthodontist are used to
moving teeth and as such the focus is to
move the teeth so that the teeth bite in
the same place as when the joint is
balanced. But there is little explanation
to why this difference occurs. From a
postural perspective a whole different
approach seems logical and almost too
simple. People who are a little short of
tongue space tend to rest with their
tongue between the teeth, as this is
comfortable and since this is their
habitual postural position where the
mandible sits for most of the time, the
jaw joint remodels to be balanced in
this position. When they bite together
the joint is not centric so it's not balanced.
It is over-closed with the head of the
jaw joint set in the top back of the
joint, often squeezing the disc out of
the way. If they bite hard or Cclench
possibly due to periods of stress it is
possible to cause great damage to the
joint, and for the disc to dislocate,
worsening over time. This situation does
not resolve as the difference between
the postural and the biting revision
remains different. Placing a splint helps
in the short term as this makes an
artificial biting position that matches
the centric or postural positions. In the
long term the splint usually disturbs
the postural position, often with the tongue
resting between the splints and the
teeth, requiring increases in the splint
thickness to compensate. The next step of
changing the bite to match the splint is
difficult, costly and, it would seem,
illogical. From an orthotropic
perspective it makes more sense to
change the centric position to match the
biting position, especially as there's no
guarantee that the centric position will
not change after the bite has been
changed. The treatment involves wearing
an appliance all night every night. That
Teaches the wearer to hold their teeth
lightly together.
They are taught to engage the reciprocal
antagonists of the jaw closing muscles
to prevent clenching. If, for at least a
third of the time, the teeth are held in
this position - or more if the training is
a factor - then the joint will recognize
this point so reorganize to take loading
in this position. At the same time both
the upper and lower arches are widened
a little to give a little more space for
the tongue, so that it does not have to
rest between the teeth and not encroach
the airway.