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NTI
Tension Suppression System
The most effective FDA-approved method of
migraine prevention
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Temporomandibular disorders all have one perpetuating and/or causative
factor in common:
an excessive motor activity of the mandibular division of the
trigeminal nerve, that is, excessive occluding of the teeth.
Four factors
dictate the presenting signs and symptoms:
--Intensity of the
occluding;
--Frequency of the
occluding;
--Duration of the
occluding;
--Degree of
condylar translation and direction of the pull on the condyle
by the lateral pterygoid during the occluding event .
Of those four
factors, the most significant is the intensity
of the event. The ideal occlusal splint (left) cannot reduce the
intensity of nocturnal clenching, in fact, it allows clenching to
exceed voluntary maximum.
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In the animation above, the condyles are
"stable" during the occluding
event (sometimes referred to as "posterior support for the
joint). Due to the bilateral intensity of elevation, (that is,
clenching), neither lateral pterygoid has the ability to translate its
condyle and disclude the teeth. Only until the temporalis' relax
do all the teeth disclude.
When temporalis
relaxation and ipsilateral translation of the condyle occurs
unilaterally (right), the remaining scheme of occluding teeth becomes
an influential factor in the presenting signs and symptoms, of which,
contacting canines during mandibular depression ("canine rise) is
highly desirable, as it minimizes condylar translation and muscle
intensity, while directing the vector pull on the condyle more
anteriorly than a posterior contact. (The ideal directional pull of the
LP's on the condyle is anteriorly, and the more translated the condyle
is during parafunctional occluding events, the more pathologic strain
on the condyle and shearing load to the disc there is)
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When lateral pterygoids bilaterally
protrude the mandible (left: while teeth are still occluding, from A to
B), or when there is an incisor-to-incisor contact during functional
closure, clenching (elevation) intensity is minimized. The force
vectors of the pull of the lateral pterygoids on the condyles brace and
support the condyle anteriorly against the slope of the eminence.
Therefore, the
provision of "incisal guidance" is the optimal goal of nocturnal
occlusal splint therapy.
Below, an NTI
device provides for incisal guidance in the centered clench and in an
excursive occluding event.
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An NTI
device is a modified, or enhanced, anterior bite stop
which prevents reciprocating posterior tooth contacts,
or canine contact on the device or another tooth.
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It is
therefore imperative to prevent the canine from receiving stimulation
though its long axis,
as doing so allows
for increased intensity of parafunctional events.
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In
order to keep condylar translation to a minimum,
the VDO of the
Discluding Element (DE) needs to be minimized.
(excessive VDO of
the DE shown in yellow below)
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Resistance schemes during
parafunction and the forces directed:
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Below,
blue vectors represent the SHLP, orange vectors the IHLP:
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