In vitro comparison of two techniques of rigid internal fixation used for mandibular advancements : biomechanical study in sheep mandible

Abstract

The main methods for fixation of bilateral sagittal osteotomy are the use of monocortical plates in a non-compressive form and the installation of bicortical positional screws, each of them presenting advantages and disadvantages. The two methods are described as rigid and, thus, eliminate the need for postoperative maxillomandibu- lar fixation. Nevertheless, there are two aspects to be cleared: the first one is if both the fixation forms promote the same rigidity and the second, how much load each fixation form can tolerate. The result was that the force, ne- cessary to make the system fail, is very higher in case of the fixation made with bicortical screws, i,e., this type of fixation shows a higher mechanical strength. Key words: osteotomy, bone screws, bone plates, mandibular advancement.