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The effects of PROPEL Micro-Osteoperforations (MOPs) on
Tooth Movement and Bone in the Beagle Maxilla
Chris L. Cramer DDS MS MBA TAMHSC Baylor College of Dentistry
Orthodontic Class of 2016
Copyright Chris L. Cramer DDS MS MBA – 4/24/2017
Orthodontic Treatment
• Non-EXT: 20 to 27 months
• EXT: 25-35 months
• Risks associated with longer
treatment time include
decalcification, root resorption,
patient burnout, and others
Buschang et al 2012, Kurol et al 1996, Segal et al 2004
0 m
m
1 m
m
2 m
m
18
g C
losin
g L
oop
60 g
Clo
sin
g L
oop
Tw
in
Dam
on
Sm
art
Clip
100 g
NiT
i C
CS
15
0-2
00 g
NiT
i C
CS
40
0-4
50 g
Ela
s M
od
Cort
icoto
my
Tooth Movement
(mm / month)
1.08 mm / mo (Syst Rvw) Burrow et al 2010, Samuels et al 1998, Iwasaki et al
2000, Ren et al 2003, Cho et al 2003, Iino et al 2007
Mandibular Tooth Movements
Experimental: 2.4 mm Control: 1.3 mm Sanjideh et al, 2010
Experimental
Control
Peak RAP = 3-4 weeks
Sanjideh et al 2010 Mostafa et al 2009 Cho et al 2007
Issues with Corticotomies
• Significant Procedure
• Expensive
• Surgical risk
• Recession
• Flapless Corticotomies
– Less invasive
– Bur, Piezocision, Endo Tip…
– PROPEL Device (MOPs)
Micro-osteoperforation (MOP)
Teixeira et al 2010
• 3x 0.5 diameter x 0.5 mm deep perforations
• Rat, 51 g force
– Ortho + Flap + MOP > Ortho + Flap
– “MOPs double tooth movement”
– “MOPs don’t need to be close to the tooth”
The small rat molar and the relatively high
applied force do not scale to the human
patient (equivalent of 5.5 pounds)
New York University filed a patent on
microperforations when this study was
completed. Propel Orthodontics Inc. licensed
this patent from NYU. Bias?
MOP Studies - Rats
• 10 MOPs (same size as Teixeira et al 2010)
• Raised a flap on MOP side only (Teixeira et al 2010 raised flaps bilaterally)
• No statistically significant change in tooth movement beyond 1 week
* P < 0.05
*
Baloul et al 2011
Rat studies of MOPs give mixed results.
MOP Studies - Dogs
• Flapless
• 25 bur perforations
• Depth of cortex
• Repeated monthly
– 1st Month – Faster
– 2nd Month – Same
– 3rd Month – Slower Safavi et al 2012
Flapless Cortical Damage
• Bone awl
• 60 holes, 0.5 mm x 1.9 mm deep
• Reduced cortical bone volume &
density
• No change in bone density or
volume
• No difference in tooth movement
Swapp et al 2012
PROPEL Clinical Study • Twenty Class 2 Div 2 Pts
• EXT U4s then heal 6 mo
• Set of 3 PROPEL MOPs
• U3 retraction for 1 month
• Results
– 2.3x increase over control
– Control ~0.6 mm
– PROPEL ~1.3 mm
Alikhani et al 2013
0 m
m
1 m
m
2 m
m
18
g C
losin
g L
oop
60 g
Clo
sin
g L
oop
Tw
in
Dam
on
Sm
art
Clip
100 g
NiT
i C
CS
15
0-2
00 g
NiT
i C
CS
40
0-4
50 g
Ela
s M
od
Cort
icoto
my
Tooth Movement
(mm / month)
1.08 mm / mo (Syst Rvw) Burrow et al 2010, Samuels et al 1998, Iwasaki et al
2000, Ren et al 2003, Cho et al 2003, Iino et al 2007,
Alikhani et al 2013
Control
Purpose
– Evaluate how PROPEL MOPs effect bone
and ultimately tooth movement in a large
scale animal to help understand their effect in
our patient population.
+ = Effect on Bone?
Significantly Faster?
Experimental Design
– Subject: Beagle (Maxilla)
– Split mouth:
• Control (No PROPEL MOPs)
• Experimental (PROPEL MOPs)
– 7 Subjects (sufficient statistical power)
– Randomized
– Blinded
Extractions /
Appliances
• Extract 3rd premolars
• Heal 1 month
• 8 MOPs on Exp side
• Retract 2nd Premolars
• Collect LOTS of Data!
X
Data
• Caliper Measurements
• Radiographic Meas
• Bone Density
• Bone Volume
• Histology
• Histomorphometry
Tooth Movements - Overall
0
0.2
0.4
0.6
0.8
1
1.2
0 1 2 3 4 5 6 7 8
Ch
an
ge (
mm
)
Control Experimental
Caliper Measurements
Difference = 0.05 mm
0
0.2
0.4
0.6
0.8
1
1.2
0 1 2 3 4 5 6 7 8
Ch
an
ge (
mm
)
Weeks
Control Experimental
Radiographic Measurements
Difference = 0.27 mm
p = 0.237
p = 1.000
p = 0.866
p = 0.866
p = 0.670 p = 0.445
p = 0.527 p = 0.528
P > 0.05 means
NOT significant
Conclusion #1
Overall increases in tooth movements produced
with MOPs are small, indicating the extent of
their effects are limited.
Tooth Movements - Early
0
0.2
0.4
0.6
0.8
1
1.2
0 1 2 3 4 5 6 7 8
Ch
an
ge (
mm
)
Control Experimental
0
0.2
0.4
0.6
0.8
1
1.2
0 1 2 3 4 5 6 7 8
Ch
an
ge (
mm
)
Weeks
Control Experimental
Increased tooth movement in
first 1 to 3 weeks
p = 0.237
p = 1.000
p = 0.866
p = 0.866
p = 0.670 p = 0.445
p = 0.527 p = 0.528
Caliper
Radiographic
Sanjideh et al, 2010
Conclusion #2
MOPs may produce slight, early increases in
tooth movements.
Bone Density and Bone Volume
0
1000
2000
3000
4000
5000
6000
Adjacent Alveolar Bone
mg
HA
/ c
m3
Ctrl Exp
p = 0.237
0
0.1
0.2
0.3
0.4
0.5
Adjacent Alveolar Bone
BV
/ T
V F
ract
ion
Ctrl Exp
p = 0.398
Bone Density Bone Volume
Swapp et al 2012
No difference
in density or
volume
No difference
in tooth
movements
Conclusion #3
MOPs placed three or more millimeters away
do not increase tooth movements because they
have no major effect on the amount or density
of bone adjacent to the teeth being moved.
What happens near MOP?
VanGemert et al 2016
Similar Microcrack Regions Empty Lacunea
VanGemert et al 2016
Major density effect < 1.5 mm away
VanGemert et al 2016
M indicates an MOP. MR indicates a mesial root. DR indicates a distal root. ES
indicates the extraction socket.
1 mm
Control Experimental
MOP
MOP MOP
MOP 1 mm
Root Root Root (Root)
P2 P2
Ext
Site Ext
Site
Histomorphometry
No side differences
LH Left 4 (5X)
C P1 P2 P3 P4 M1
Conclusion #4
The effect of the MOP on bone density and
turnover is limited to 1 to 1.5 mm from the
edge.
Tooth Movements - Early
0
0.2
0.4
0.6
0.8
1
1.2
0 1 2 3 4 5 6 7 8
Ch
an
ge (
mm
)
Control Experimental
0
0.2
0.4
0.6
0.8
1
1.2
0 1 2 3 4 5 6 7 8
Ch
an
ge (
mm
)
Weeks
Control Experimental
Increased tooth movement in
first 1 to 3 weeks
p = 0.237
p = 1.000
p = 0.866
p = 0.866
p = 0.670 p = 0.445
p = 0.527 p = 0.528
Caliper
Radiographic
Slight Distant (up to 4 mm) Demineralization
VanGemert et al 2016
Conclusion #5
The early, temporary increases in tooth
movement must have been due to distant
demineralization.
Clinical Implications
• This study suggests following PROPEL
recommendations on MOP placement will not have
a significant affect on tooth movements
– MOPs are too far away
– Injury is too minimal
Cohen et al, 2010
More Injury
Faster Movement
Less Injury
Slower Movement
RA
P
RA
P+ 20x
20x
A, 20x
20x
Insult RAP (increased osteoclasts and
osteoclastic activity/unit area)
Mesial
Inter-radicular
Buccal
Mesial Bundle
RAP+ had less bone, and
especially, less dense bone,
than the RAP group
Clinical Implications
Thank You!
Dr. Peter
Buschang
Dr. Phil
Campbell
Dr. Lynn
Opperman
Dr. Larry
Tadlock
Funding from
the Robert E.
Gaylord
Endowed
Chair