Dentaltown October 2020 - 50

continuing
education
by Dr. Mike Racich
Dr. Mike Racich, a 1982 graduate from University
of British Columbia, has a general dental practice
emphasizing comprehensive restorative dentistry,
prosthodontics and TMD/orofacial pain. Racich
is a member of many professional organizations
and has lectured nationally and internationally on
subjects relating to patient comfort, function and
appearance. He is a fellow of the Academy of General
Dentistry and the American College of Dentists
as well as a diplomate of the American Board of
Orofacial Pain and the International Congress of Oral Implantologists.

Introduction
When planning extensive restorative dental/prosthodontic procedures or seeking to stabilize interarch
relationships (before periodontal surgery or after
orthodontic treatment), mutually protected occlusal
schemes are often chosen by dental practitioners.1-11
The glossary of prosthodontic terms defines a
mutually protected occlusion as "an occlusal scheme
in which the posterior teeth prevent excessive contact
of the anterior teeth in maximal intercuspal position
(MIP), and the anterior teeth disengage the posterior
teeth in all mandibular excursive movements."12
Achieving reproducible posterior tooth contact in
MIP is facilitated via performing an occlusal equilibration
(OE), whereby MIP is coincident with centric occlusion
(CO).12 OE is generally a subtractive procedure done
via selective odontoplasty, but can also be additive
for occlusion vertical dimension (OVD) increasing or
restoration.13,14
This course describes a subtractive OE technique
to facilitate mutually protected occlusal schemes via
inclined plane odontoplasty.

OE technique
Occlusal equilibration should be done in a stress-free
environment with all participants comfortable and relaxed;
consider positioning the patient at a 20- to 30-degree
angle to the horizon, depending on the patient's physical
stature.15 (See table on facing page.)

Assess the existing OVD in the patient's habit bite
(MIP). If adequate, make a mental note of an anterior
tooth relationship, such as the right cuspids, and prepare
to equilibrate the dentition to a reproducible endpoint (i.e.,
CO) that does infringe on this accepted OVD. In other
words, equilibrate the posterior dentition to the original
anterior tooth relationship (Fig. 1, p. 52). Anterior open
bite cases require comprehensive orthodontic evaluations
before subtractive OE can be performed.16
Utilizing a mandibular guidance technique of preference, such as centric relation (CR), bring the mandibular
dentition into contact with the maxillary dentition and
locate the first tooth contact.17-22
Have the patient squeeze his or her teeth together
and evaluate the CR (guided fi rst contact), then MIP
slide (forward/back, left/right). Generally, the mandible
will move forward from distal inclines of mandibular
teeth and/or mesial inclines of maxillary teeth contacting
(Figs. 2 and 3, p. 52).
For right or left mandibular deviations, the concept
of "working" and "nonworking" interferences is utilized,
whereby the mandible will be directed in the opposite
direction (Figs. 4 and 5, p. 52).12,23 For left mandibular
CR to MIP deviations, what would be any right-sided
"working" and left-sided "nonworking" interferences if the
mandible was to go to the right in a mutually protected
occlusal scheme are the responsible contacting surfaces
for this motion. Conversely, for right mandibular CR to
MIP deviations, what would be any left-sided "working"

Disclosure:

The author declares that neither he nor any member of his family has a financial arrangement or affiliation with any
corporate organization offering financial support or grant monies for this continuing dental education program.

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Dentaltown October 2020

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