Finite element analysis between Hunsuck/Epker and novel modification of Low Z plasty technique of mandibular sagittal split osteotomy

The Novel Modification of Low Z plasty (NM-Low Z) technique of bilateral sagittal split osteotomy was recently proposed. The osteotomy line was modified more inferiorly compared to the conventional; Hunsuck/Epker (HE) technique. The NM-LowZ technique enhance mandibular setback distance and degree of rotation in severe skeletal discrepancies. This study was aimed to investigate biomechanical behavior under simulated forces and to compare between NM-Low Z and HE technique onmandible with Class III skeletal deformity at 1-week, 3-week and 6-week postoperatively. Physiological muscular and occlusal loads were simulated by finiteelement (FE) method. The stress on miniplate, screws, and bone were observed and compared between two models. Elastic strain at the fracture site was observed for optimal bone healing capacity. NM-Low Z model exhibited lower stress than HE modelin every stage post-operatively. Both models demonstrated elastic strain within normalrange for bone healing. In summary, biomechanical behavior of NM-Low Z technique is comparable to the conventional EH technique. NM-Low Z could facilitate postoperative skeletal stability by reducing stress on fixation materials while accompanying the bone healing process.