Abstract

In this study an attempt was made to determine the amount of interproximal contact disruption necessary to initiate an electromyographically discernable deviation in the masticatory musculature. Ten adult subjects with adjudged normal occlusions were used. An additional study was under taken to determine the time necessary for the right and left temporal and masseter muscles to accommodate this disruption. Myographic recordings were taken of the subjects while closing firmly in centric occlusion and chewing Dentyne gum first on the right side, then on the left.

Contact disruption was accomplished with a metal shim of .003 inch thickness and later in the following experiment, with one of .006 inch thickness placed between the lower right first molar and the lower right second bicuspid. Myograms were then taken upon insertion and at ten minute intervals as long as necessary to establish the recovery pattern up to one half an hour, then at two, six and twenty-two hour intervals if adaptation was not complete.

Following these recordings an .008 inch occlusal onlay was placed on the lower right first molar of each subject regardless of his reactions to contact disruption and a myographic tracing was done immediately.

Of the ten subjects studied, four showed suppression of amplitude when closing in centric occlusion after insertion of an .003 shim. Two of these four showed suppression to a lesser extent when chewing gum on the right side and then on the left.

After insertion of an .006 shim six subjects showed suppression in centric occlusion, four in chewing on the right and five in chewing on the left. Again the amplitude suppression in the chewing strokes was less than that in centric occlusion.

All ten exhibited significant amplitude suppression after insertion of the .008 onlay in centric occlusion and the chewing cycles as well. The majority of subjects (4) showed return to peak amplitudes within twenty minutes of .006 shim insertion, one within two hours and the last within six hours.

Interproximal contact disruption of .003 inch between two teeth is sufficient to elicit abnormal neuromuscular responses in four of the ten subjects with normal occlusion used in this study.

Interproximal contact disruption of .006 inch between two teeth is sufficient to elicit abnormal neuromuscular responses in six of the ten subjects with normal occlusion used in this study.

An occlusal prematurity of .008 inch is sufficient to produce neuromuscular aberrations in all of the same ten subjects.

The temporal and masseter muscles show a great degree of adapt ability to contact disruption witnessed by their rapid return to normal function.

The same apparent interferences in centric occlusion and inter proximal contact areas will not yield the same muscular response from individual normal subjects.

The masticatory musculature exhibits the phenomenon of enhancement when accommodated interferences are removed.

LLU Discipline

Orthodontics

Department

Dentistry

School

Graduate School

First Advisor

Thomas J. Zwemer

Second Advisor

Howard W. Conley

Third Advisor

Guy M. Hunt

Fourth Advisor

Roger H. Helmendach

Degree Name

Master of Science (MS)

Degree Level

M.S.

Year Degree Awarded

1964

Date (Title Page)

6-1964

Language

English

Library of Congress/MESH Subject Headings

Electromyography; Masticatory Muscles

Type

Thesis

Page Count

vii; 75

Digital Format

PDF

Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.

Collection

Loma Linda University Electronic Theses and Dissertations

Collection Website

http://scholarsrepository.llu.edu/etd/

Repository

Loma Linda University. Del E. Webb Memorial Library. University Archives

Download

Share

COinS