2010 RWISO Journal - Roth Williams International Society of ...

Physiologic Treatment Goals in Orthodontics
Andrew Girardot, DDS, FACD
and R e W Gi R a R d o T , ddS, Facd
ragfishing@hotmail.com
■ Graduated from USC School of
Dentistry (DDS), 1968
■ Graduated from USC School of
Dentistry, Dept. of Orthodontics
(certificate in orthodontics), 1972
■ Part-time Faculty University of
Colorado, School of Dentistry,
Dept. of Orthodontics
■ Cofounder, codirector and faculty,
Roth Williams USA, 1997-present
Introduction
For the better part of a hundred years, orthodontists have
used Angle’s classification as a means of communication.
When we say “Class I,” orthodontists share the same image,
which is generally a positive concept of how teeth should fit
together. There certainly can be a Class I case with problems,
but Class I is the first major step in describing optimal tooth
relationships. To this day, Angle’s Class I describes a morphologic
treatment goal for the orthodontic specialty.
Why do we not have a similar physiologic treatment
goal? Often we talk about “occlusion” in orthodontics, but
it clearly means different things to different people. The term
occlusion lacks the communication value of Class I. A “good
occlusion” is a nebulous term that varies depending on the
person using it. We have a communication problem. We enjoy
general agreement, and hence communication clarity,
regarding morphology, but this is not the case for physiology.
It would certainly be of value to our patients and the
orthodontic specialty if we had a clear definition of what
constitutes optimal physiology or “good occlusion.”
As in all biologic systems, the structural elements of
the human gnathic system have evolved to perform best un-
Summary
Angle’s class I has long served the orthodontic specialty as a morphologic
treatment goal and a means of communication. Certainly a physiologic
treatment goal would be of equal value. There are sound data to define and
support such a physiologic goal, which can help orthodontists to better serve
their patients, communicate with other dental professionals, and avoid numerous
clinical problems.
der certain conditions of form and function. For example,
there is considerable evidence to support a clear definition
of healthy function for the temporomandibular joint in its
loaded state, such as during a swallow. When loaded, the
condyle should be positioned upward, forward and midsagittally.
This definition of optimal joint position is agreed
upon by most authorities1-15 and is well supported by the
literature. 16-36 Okeson defines this as the “most musculoskeletally
stable position of the mandible.” 7(112) There also are
data indicating the optimal relationship of the condyle, disc,
and eminence when the mandible is moving into or out of
the loaded position. In this condition, there should be constant
contact between the condyle, disc, and eminence. 37-40
There are numerous data indicating that neuromuscular
function is highly influenced by tooth contacts and tooth positions.
41-55 For example, as the mandible moves into and out
of intercuspation, guidance from properly positioned anterior
teeth aids in separating the posterior teeth. This reduces
the activity of the powerful elevating muscles, which, in turn,
downloads the system while facilitating constant contact between
the condyle, disc, and eminence. 39,43,46,47,55-64
Thus, current data point to an optimal physiologic rela-
RWISO Journal | September 2010
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