Three Dimensional Quantification of

Post-Surgical Condylar Displacement

PAULA ZABALEGUIDan Grauer DDS, MS, PhD & Michael Gunson DDS, MD

Thomas M. Graber Award of Special Merit

P U R P O S E O F O U R S T U D Y

To measure, in three dimensions,

translation and rotation movements

of the condyle after orthognathic

surgery

M AT E R I A L S

17 Consecutive Patients [10M, 7F]

Skeletal Class II Or Class III Malocclusion

Pre-surgical Orthodontic Treatment + Bi-maxillary Surgery (Same Oral

Surgeon)

Maxillary Le Fort I Osteotomy & BSSO

Rigid Fixation (Plates)

Full head CBCT scans, pre surgery and 2 weeks after surgery

M E T H O D

1) Segment the Region of Interest: condyles and fossae, pre and

post surgical

2) Export as separate surfaces

3) Superimpose on Glenoid Fossa

4) Measure condylar displacement:

Translation (mm): x,y,z

Rotation (degrees): x,y,z

1. Segment the Region of Interest

2. Export as Separate Surfaces

3. Superimpose on Glenoid Fossae

4. Measure Condylar Displacement from PreSurgical (Blue) to Post Surgical (Red)

0,00

1,00

2,00

3,00

4,00

x y z

0

4

10.15

-3.80

0.78

AVERAGE CONDYLAR TRANSLATION (MM)

-3.80

0.78

0.15

R E S U LT S

-0.30

0.63

-0.27

AVERAGE CONDYLAR ROTATION (º)

0,00

1,00

x y z

000

0,063

0,3070,277

R E S U LT S

D I S C U S S I O N

T R A N S L A T I O N Y ( A N T E R O P O S T E R I O R )

What i s th i s k ind o f

movement due to?

What i s th i s k ind o f

movement due to?

D I S C U S S I O N

A N T E R O P O S T E R I O R R O T A T I O N

What i s th i s k ind o f

movement due to?

D I S C U S S I O N

M E D I O L A T E R A L R O T A T I O N

Why d i d n ’ t w e f i n d t h e s e k i n d s o f

m o v e m e n t s ?

D I S C U S S I O N

M E D I A L A N D S U P E R I O R M O V E M E N T

C A S E P R E S E N TAT I O N

B l u e = b e f o r e s u r g e r y R e d = a f t e r s u r g e r y

C O N C LU S I O N S

1. A method to measure Condylar Displacement in 3 planes of space

was established, both for rotation and translation

2. Posterior displacement

3. Anteroposterior Rotation

4. MedioLateral Rotation

5. Surgical stability

Advanced Orthodontic Program :

University of Southern Cali fornia

Dr. Dan Grauer

Dr. Michael Gunson

A C K N O W L E D G E M E N T S