Biomechanical evaluation of hybrid fixation method of sagittal split ramus osteotomy in mandibular advancement

Abstract

Purpose: In this study, eight different fixation methods applied after sagittal split ramus osteotomy (SSRO) were compared experimentally.

Materials and methods: SSRO was performed to 48 sheep hemimandibles in eight groups of 6 each. Group A- a four hole standard miniplate; Group B- a four hole standard miniplate and one bicortical screw; Group C-a four hole locking plate; Group D-a four hole locking plate and one bicortical screw; Group E-a six hole straight miniplate; Group F-a six hole straight miniplate and one bicortical screw; Group G- a sliding plate, which was specifically designed for SSRO; Group H- sliding plate and one bicortical screw.

Results: In terms of measured values of displacement, the highest degrees of displacement were observed in decreasing order in Groups G, C, A, and E. The least displacement values were detected in Groups H, F, D and B with values being very close to each other. For linear force applied up to 70N, 3 mm or higher displacement values were not seen in any fixation system.

Conclusion: According to the results of study, all systems are suitable for clinic usage. However, intermaxillary fixation or functional elastics may be needed for sliding plate systems during the healing period of hard tissue.

Keywords: Biomechanical stability; Hybrid fixation; Sagittal split ramus osteotomy.