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Apparatus
Myotronic K-6 system was applied to record
the mandibular movement velocity. The
mandibular movements were recorded both
in sagittal and frontal planes simultaneously.
The photo 1 scheme of the K-6 system
was used first to trace the trajectory of
the mandibular movement sagitally and
horizontally.
During mandibular movement, the photo 2
scheme recorded the simultaneously vertical
velocity and the frontal view of deviation. Five
consecutive open-close motion velocity were
recorded in five parameters: (1) the maximal
opening velocity, (2) the average opening
velocity, (3) The maximal closing velocity,
(4) the average closing velocity and (5) the
terminal velocity of terminal teeth contact.
Procedure
During the experiment, the subject was
seated comfortably on a dental chair in an
upright position. The labial surface of the
mandibular incisors and gingivae was dried
with gauze and a magnet (Myotronics Co.
Seattle WA, USA) with Urehesive (Bristal-
Myers Squibb CO. ST. Louis , MO. USA) was
stuck horizontally on to the labial surface of
lower incisors according to the instruction of
the operating manual. If the subject is a deep
overbite, the magnet would be placed on the
lingual surface of the mandibular incisors
alternatively. According to the guidance of
operating manual, the sensor array was
aligned and the program was set ready to
record the parameters.
Photo 1 of the Myotronic K-6 system traced
the pathway of mandibular movement in
sagital and frontal planes during opening and
closing of the mouth. It will be the baseline
data to check if the test subjects open wide
enough at the same magnitude during the
subsequent experimental session.
The photo 2 scheme of the K-6 system
was used subsequent l y to record the
ve l oc i t y o f mand i bu l a r movemen t i n
vertical plane and frontal view of lateral
deviation simultaneously during opening
and closing movements. The subjects were
instructed to watch the monitor and perform
five continuous open-close mandibular
movement (open from centric occlusion to
the maximum opening position, and return
to centric occlusion again). The open-close
motion analyzed by the photo 2 scheme
was record into five categories (1) maximum
open velocity (2) average opening velocity
(3) maximum closing velocity (4) average
closing velocity and (5) maximum velocity
of terminal tooth contact. After that, subjects
were asked t o c l ose eyes , t he same
procedure was followed again to compare
the effect of visual Feedback on the velocity
of mandibular movement. All velocity records
were saved in the disks for later analysis.
Data analysis
All the recorded data were saved in disks
and processed by Excel and Wink. The
means of five consecutive opening-closing
velocity was used to compare the different
臺灣口腔醫學工程學會會誌
No.
13
Taiwan Oral