Dawson Classification Revisited
The most commonly used occlusal classification in dentistry, the Angle’s classification,
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fails to observe the relationship of the teeth to the TMJs or consider
the health, position, or condition of the
TMJ. By contrast, in the
Dawson classification,
6 the health and stability of the joint
is a primary concern, as well as the relationship of the joints to the
maximal intercuspation. A joint that is changing position or
deteriorating will directly impact the arch-to-arch relationship and
ultimately radically affect occlusion.
Dawson I: Maximum intercuspation isin harmony with the CR.
This is one of the primary goals for the completion of occlusal
therapy for a healthy TMJ. The teeth occlude in maximum intercuspation
when the condyles are in CR (which is the maxillo-mandibular
relationship when the properly aligned, condyle-disc assemblies are in
the most superior position against the eminentiae, irrespective of tooth
position or vertical dimension).
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Dawson Ia: Maximum intercuspationis in harmony with ACP.
This is one of the primary goals for the completion of occlusal
therapy for a disordered TMJ. The teeth occlude in maximum
intercuspation when the condyles are in ACP (the manageably stable
relationship of the mandible to the maxilla that is achieved when
deformed TMJs have adapted to a degree that they can comfortably accept
firm loading when completely seated at the most superior position
against the eminentiae).
8 Technological advances using
conventional computed tomography images or cone-beam computed tomography
(CBCT) are indispensible aids in determining when a disordered TMJ is
stable.