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

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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

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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

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Control Experimental

Caliper Measurements

Difference = 0.05 mm

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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

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Control Experimental

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0.8

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ge (

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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

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mm

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Control Experimental

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0.2

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0.6

0.8

1

1.2

0 1 2 3 4 5 6 7 8

Ch

an

ge (

mm

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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