Maxillary fragment stabilization after Le Fort I fracture with 1 screw pair per plate.
OBJECTIVE
The aim of the present study was to determine whether plates with only 1 screw pair can be used for Le Fort I fracture management. Good postoperative results motivated the direct application of mandible fixation principles to the fractured midface region without additional experimental research. However, the amount and distribution of the forces in the midface region is different from those on the mandible.


METHODS
Testing was conducted on plastic anatomic models. The validity of the experimental model was tested before the fixation techniques were compared. Standard miniplates and miniscrews were used for fixation of the maxilla. The model surface strain analysis was conducted using the noncontact object grating method, which enabled the surface strain measurement without direct influence on the measured model.


RESULTS
In 2 screw pair fixation, the outer screw pair has little effect on the local strain distribution, but it lowers the contact forces along the crack. One screw pair fixation is stable enough for fixation, but it has a greater strain peak at the crack edges.


CONCLUSIONS
Our results showed that 1 screw pair per plate was enough for stable fixation, and 2 or more screw pairs should only be used when the bone fragment at the fracture site cannot sufficiently transmit forces along the crack.
Knežević
Predrag
P
Department of Maxillofacial Surgery, Zagreb School of Dental Medicine, Zagreb, Croatia.
Grgurević
Lovro
L
Uglešić
Vedran
V
Grgurević
Jakša
J
Drvar
Nenad
N
Kodvanj
Janoš
J
D000539:Alveolar Process / Q000503:physiopathology; D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008437:Maxilla / Q000503:physiopathology; D008440:Maxillary Fractures / Q000145:classification / Q000601:surgery*; D008953:Models, Anatomic; D009295:Nasal Bone / Q000503:physiopathology; D010781:Photography / Q000379:methods; D010969:Plastics / Q000737:chemistry; D013314:Stress, Mechanical; D015050:Zygoma / Q000503:physiopathology
D010969:Plastics