Mechanical analysis of maxillofacial miniplates.

The effect of compression and tensile forces on different types of maxillofacial miniplates was measured, in both as supplied and after bending states. Tests showed all plates showed values of tensile force at failure in excess of that found in most clinical situations; twisting through 90 degrees about the long axis had little effect. In flatwise bending tests there was a wide scatter of values of bending stiffness and ultimate load, indicating that some plates may be stronger than necessary. Repeatedly bending the plates reduced their bending stiffness, particularly in the continuous holed plates, and increased their ultimate load to failure. Values of bending stiffness and ultimate load were much larger when bending in the edgewise direction, with large differences between manufacturers. The data generated in the current study may assist the surgeon in deciding which type of plate to select for a particular clinical situation.