Force level and strain patterns during bilateral mandibular osteodistraction.
OBJECTIVE
Recent reports have demonstrated that device orientation is important during mandibular distraction osteogenesis. The purpose of this study was to evaluate the force level and strain patterns on the mandible during bilateral osteodistraction with devices oriented either parallel to the body of the mandible or parallel to the sagittal axis of distraction.


METHODS
Five unembalmed human cadaver mandibles were placed in a specially designed apparatus for stabilization of the proximal segments during distraction. A force transducer was attached to the lateral aspect of the inferior ramus, and strain gauges were attached to the mandibular bone segments proximal and distal to the distraction device. Lateral force and bone strains were then measured at 5 and 10 mm of distraction. Osteodistraction proceeded first with the devices placed parallel to the mandibular body, then parallel to the axis of distraction.


RESULTS
Significantly greater lateral forces were seen when the devices were oriented parallel to the mandibular body. With this device orientation, increased tensile strains were seen at the labial symphysis and medial ramus, and increased compressive strains were found at the lingual symphysis and lateral ramus. However, when the devices were oriented parallel to the axis of distraction, the forces and strains were not detected.


CONCLUSIONS
The results suggest that device orientation has important biomechanical effects on lateral forces and strain patterns during mandibular osteodistraction.
Cope
J B
JB
TAMUS-Baylor College of Dentistry, Department of Orthodontics, Dallas, TX 75266-0677, USA. jasoncope@orthodontist.net
Yamashita
J
J
Healy
S
S
Dechow
P C
PC
Harper
R P
RP
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002102:Cadaver; D003799:Dental Stress Analysis / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000502:physiology / Q000601:surgery*; D008875:Middle Aged; D019857:Osteogenesis, Distraction / Q000295:instrumentation* / Q000379:methods / Q000706:statistics & numerical data