Photoelastic analysis of miniplate osteosynthesis for mandibular angle fractures.
OBJECTIVE
The purpose of this study was to reassess Champy's findings, which were instrumental in justifying the theory of tension band plating for mandibular angle fractures.


METHODS
Ten anatomically correct mandibles were fabricated with a photoelastic resin. In five mandibles, angle fractures were created and fixed with a superior border miniplate; five uncut mandibles served as controls. Each mandible was loaded in a manner that simulated physiologic conditions. The internal stress patterns were preserved within the models by completing a stress freezing cycle.


RESULTS
The stress patterns in the experimental mandibles virtually replicated the patterns seen in the controls. Stress fringes were present surrounding the outer screws, indicating that these screws were subjected to pull-out forces.


CONCLUSIONS
There is greater force on the outer screws that may contribute to fixation failure. The theory of tension band plating for mandibular angle fractures is accurate but Champy's model is oversimplified.
Rudman
R A
RA
Department of Oral and Maxillofacial Surgery, University of Florida, Gainesville, USA.
Rosenthal
S C
SC
Shen
C
C
Ruskin
J D
JD
Ifju
P G
PG
D001718:Birefringence; D001732:Bite Force; D001860:Bone Plates; D003799:Dental Stress Analysis; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D006801:Humans; D008337:Mandibular Fractures / Q000601:surgery*; D008953:Models, Anatomic; D013314:Stress, Mechanical; D013718:Tensile Strength