Orthodontic courses by Indian dental academy

Functional Assesment Of Lateral Pterygoid,
Masseter & Temporalis In Cl- II Div-1,
Hypodivergent Patients
A “M” Mode Echomyographic study
{ A New Technique With Ultra-Sonogram(U.S.G)}
www.indiandentalacademy.com

AIM
This study evaluates the
functional status of the
Masseter,Temporalis & Lateral
Pterygoid by U.S.G in
“M” mode during,
Protrusion,Lateral Excursion &
Clenching in C-II Div-1
Hypodivergent patients.

Objectives
To localize the PREDOMINANCE OF DOMINANT
CHEWING, which was cross checked by an electronic
device, the “BITE-GUAGE”.
To check for the “CONTRACTILE AMPLITUDE” &
“AMPLITUDE OF STRETCH” of the muscle, on the
dominant side, to prove “MOSS HYPOTHESIS”.
To understand muscle function during BITE
CONSTRUCTION in functional appliance therapy.
To find out the OBILITERATION OF FREE WAY SPACE.
To assess the MAXIMUM STRETCH of the muscle during
forward posturing of the mandible.www.indiandentalacademy.com

Protocol..!

 30 patients
 Both Male and Female
 Age between 10 and 14 years
 Overbite 60% to 80%
 Overjet between 5mm and 7 mm
 CI- II Molar relationship
 CI- II Canine relationship
 Low Mandibular plane angle
 Coinciding Mid-lines
 Without Latero-Occlusion
 Without Latero-Gnathywww.indiandentalacademy.com

EXTRA ORAL VIEW

INTRA ORAL VIEW

V.T.O

Considered Cephalometric
Values

FMA between 190
to 230
 IMPA between 1000
to 1050
 GoGnSn between 280
to 320
 SNA between 810
to 830
 SNB between 750
to 790
 Sum of angles(Bjork’s) < 3950
 1 to Na between 300
to 350
and
8mm and 10mmwww.indiandentalacademy.com

MATERIAL`S & METHOD`S

ULTRASONOGRAM
U.S.G used was “SIEMENS’ SONOLINE OPTIMA” with
“MEDIKA VIEW IMAGER”
With 7MHz at 3mm depth

TRANSDUCER
(Soft Tissue Probe)

“THE BITE-GAUGE”

BITE-GAUGE IN FUNCTION

POINT OF TRANSDUCER
APPLICATION

MASSETER FUNCTION

TEMPORALIS FUNCTION

PTERYGOID FUNCTION

Historical Perspective of Ultrasound.
“PIERRE CURIE”, 1880 -“PIEZOELECTRIC
EFFECT”(When mechanical stress applied to
a quartz crystal produced electric potential)
 “PIERRE CURIE”, 1881- “REVERSE
PIEZOELECTRIC EFFECT”(By applying silver
to the face of the crystal and inducing
pressure, mechanical changes occurred in the
crystal producing sound waves)

Historical Perspective of Ultrasound.
This effect is the basis for the function of
“ULTRA-SONOGRAM”.
 “TRANSDUCERS”or “SOFT TISSUE
PROBES”produce this effect by coating
silver on synthetic ceramic crystals.

Why Ultra-sonogram(U.S.G) ..?

Why not E.M.G……?

Physics Of Sound
What are sound waves
and how do they
propagate…?

Physics Of Sound (contd…)
 Sound waves are mechanical disturbances
propagating through a medium , by virtue of vibrating
the molecules in the medium and henceforth, moving
forwards.
 The speed at which the sound waves travel, depends
on the property of the medium ( Elastic, Rigid or Dense).
 Sound waves travel in different ways
-Parallel ---- Longitudinal waves
-Perpendicular---- Transverse waveswww.indiandentalacademy.com

Physics Of Sound (contd…)
 Audible range of the sound waves is between
15Hz & 20KHz , the “AUDIBLE FREQUENCY”
 If the frequency is below 15Hz, it is “INFRASONIC
FREQUENCY”
 If the frequency is more than 20KHz, it is
“ULTRASONIC FREQUENCY”
 For Medical diagnosis, the range used is between,
1 & 10 MHz (1 & 10 million Hz)

Physics Of Ultrasound
Ultrasound primarily functions using the
principle of sound wave propagation.
 Ultrasound uses a range between 1 & 10 MHz by
longitudinal sound wave propagation.
There are 4 types of modes
1. A-- Mode (Amplitude Mode):the sweep and
amplitude are assessed on the oscilloscope or
screen.

Physics Of Ultrasound
2. B- Mode ( Brightness mode ): the
brightness of the sound wave is assessed
on the oscilloscope or screen.
3. M-Mode (Motion mode ): it is used to
correlate the position & the time of the
object in motion ( primarily used in Cardiac
structures ).
4. G-Mode (Gray scale mode ): it is used
mainly to find the soft-tissue structures.www.indiandentalacademy.com

Results……!
 Every patient showed a dominant & a
non dominant side.
 Dominant side showed more stretch
reflex,but the non dominant side
showed more contractile reflex,there by
maintaining the cant of occlusion.
 It was noted that mandible could be
propelled up to a maximum of 7mm.www.indiandentalacademy.com

Results

Results (Contd…)
All patients showed a shift in the mid-line
during forward posturing of the mandible,
which attributed to the dominant side function
of the muscles.
All patients showed reduced clenching
function, because of low mandibular angle
and reduced free way space.
Dominant side showed more biting force &
hence, during bite registration 1 or 2mmof wax
should be increased on that side.www.indiandentalacademy.com

“Success...” It’s not the leap at the start
but the steady going on,that gets you
there.

“Research…!” It is to
see what everybody
else had seen and to
think what ,nobody
else had thought.

Future Scope….!
Facial asymmetries.
T.M.J. Disorders.
Longitudinal study of muscles to
ascertain the adaptation before and
after mandibular propulsion.
Using CAD-CAM technique to
measure the volume of the muscle.
To study the muscle adaptation
during pre surgical phase and to
compare it with post surgical
phase.www.indiandentalacademy.com

Orthodontic courses by Indian dental academy

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