Stability of zygomatic plate-screw orthodontic anchorage system: a finite element analysis.

Objective: To evaluate the biomechanical properties of a standard and a newly designed plate-screw orthodontic anchorage system.

Materials And Methods: A three-dimensional model of the posterior maxilla, including the zygomatic buttress region, was prepared. Insertion of standard and newly designed plates was simulated on the three-dimensional model. The effect of 200 g of orthodontic force on the plate, screws, and zygomatic bone was evaluated in three-dimensional models by finite element analysis. To determine the force distribution, Von Mises stress, principal maximum and minimum stress, and principal maximum and minimum elastic strain values were evaluated.

Results: In all plate models the highest stresses occurred on the threaded bone site where the force application unit was attached.

Conclusion: Changing the plate configuration did not affect the stress distribution in the newly designed plates. To equalize the force distribution, new plate designs that change the location of the force application unit are required.