Dentaltown January 2017 - 56

Competing concepts of "occlusion"
have been at the center of the conflicting
TMD camps over the years. The existing
controversies are one of the contributing
factors that has led to limited teaching of
occlusal concepts at the undergraduate level in
dental schools worldwide. At the heart of the
problem: Many "facts" about occlusion have
been introduced into dentistry empirically
and passed down as truths.
By examining the history of "evidence"
of occlusion, we can reveal how several
assumptions about occlusion came into
existence (and why they continue to be
taught as "science"). Exposing these potential
myths and beginning the discussion about
their origin and validity is critical to help
all dentists more thoroughly and accurately
understand the role of occlusion in their
patient's health and, consequently, improve
their daily dentistry.

The history of the
"science" of occlusion
An attempt to trace the history of the
study of occlusion takes us back to 19th-century orthodontists, who sought to decipher
nature's grand plan for the arrangement of the
dentition."At a meeting of the Philadelphia
Academy of Stomatology in 1898, Edward
H. Angle proposed that orthodontics be
based on the science of dental occlusion and
offered a definition of normal occlusion as
the ideal to be attained in the treatment of
malocclusion."1
Angle's concepts of an ideal occlusion
became widely accepted as a goal of orthodontic treatment "and the basis of normal
dental function and health." No serious
attempts to examine this hypothesis were
made until 75 years later, when the National
Institute of Dental Research and the National
Research Council of the National Academy
of Sciences "assembled three independent

56

JANUARY 2017 // dentaltown.com

panels of orthodontic experts to evaluate
research related to malocclusion, variations
in dental occlusion and disabling orthodontic
conditions."
The concepts of ideal occlusion developed by Angle, and the assumptions of
the dysfunction and pain associated with
malocclusions remained untested and
unchallenged in dentistry.1
In 1901, Karolyi's paper2 discussing
the role of occlusion in bruxism is among
the first found, but contains no references.
Without any evidence, Karoyli theorized
that "abnormality of occlusal structure was
a basis for abnormal temporomandibular
joint function, abnormal masticatory muscle
function, periodontal disease and bruxism."3
Ackerman says, referring to occlusion, that
"there was even some quasi-religious beliefs
about the nature and perfection of form that
were tied to it." This theory was continually
taught and passed down through generations.
Dr. Peter Dawson, in his third edition, refers
to the fact that "Karolyi got it right."4
In fact, the concepts became further
reinforced by Costen in 1934.5 Costen, an
otolaryngologist, used 11 case reports of
patients with decreased vertical dimension
who reported having ear symptoms that
included altered hearing ability and dizziness.
Costen referenced Goodfriend, whose work
demonstrated joint changes in cadavers, but
had no correlation to assumed symptoms,
simply stating that there are changes in the
joint structures, which occurred over time.
He made the assumption that these changes
were related to "occlusion."
Goodfriend dissected cadaver heads in
the 1920s with attempts to relate the dental
occlusion with joint anatomy.6 There was no
control group, and he had no clinical or social
histories on these cadavers. Nevertheless, he
drew the conclusion that "muscle spasms,
external injuries, deleterious habits, and
http://www.dentaltown.com
Table of Contents for the Digital Edition of Dentaltown January 2017
