Jin-Yong Lee1, Jung-Woo Lee2, Kang-Mi Pang3, Hyoun-Ee Kim4, Soung-Min Kim5, Jong-Ho Lee6. 1. Clinical Assistant Professor, Department of Dentistry, Korea University Guro Hospital, Seoul, Korea. 2. Clinical Assistant Professor, Department of Oral and Maxillofacial Surgery, Kyunghee University School of Dentistry, Seoul, Korea. 3. Clinical Assistant Professor, Department of Dentistry, Ajou University School of Medicine, Suwon, Korea. 4. Professor, Department of Materials Science and Engineering, Seoul National University, Seoul, Korea. 5. Associate Professor, Department of Oral and Maxillofacial Surgery, Seoul National University School of Dentistry, Seoul, Korea. 6. Professor, Department of Oral and Maxillofacial Surgery, Seoul National University School of Dentistry, Seoul, Korea. Electronic address: leejongh@plaza.snu.ac.kr.
Abstract
PURPOSE: The aim of this study was to evaluate the stress distribution of a magnesium (Mg)-based resorbable screw system in a bilateral sagittal split ramus osteotomy (BSSO) and to compare its biomechanical stability with those of titanium (Ti)-based and polymer (IN)-based systems. MATERIALS AND METHODS: A 3-dimensional BSSO model (10-mm advancement and setback) was constructed with Mimics. Bicortical screw fixation using Ti, IN, and Mg screws was performed with 4 different geometries of fixation. With an occlusal load of 132 N on the lower first molar, the von Mises stress (VMS) distribution was calculated using ANSYS. RESULTS: The VMS distribution of Mg was more similar to that of Ti than to that of IN. In all cases, the highest VMS was concentrated on the screw at the most posterior and superior area. Stress was distributed mainly around the screw holes (cancellous bone) and the retromolar area (cortical bone). In the advancement surgery, fixation with 5 Mg screws (5A-Mg, 99.810 MPa at cortical bone) showed biomechanical stability, whereas fixation with the same number of IN screws did not (5A-IN, 109.021 MPa at cortical bone). In the setback surgery, although the maximum VMSs at cortical bone for Mg, IN, and Ti were lower than 108 MPa (yield strength of cortical bone), Mg screws showed more favorable results than IN screws because the maximum VMSs of Mg at cancellous bone were lower than those of IN. CONCLUSION: The Mg-based resorbable screw system is a promising alternative to the IN-based system.
PURPOSE: The aim of this study was to evaluate the stress distribution of a magnesium (Mg)-based resorbable screw system in a bilateral sagittal split ramus osteotomy (BSSO) and to compare its biomechanical stability with those of titanium (Ti)-based and polymer (IN)-based systems. MATERIALS AND METHODS: A 3-dimensional BSSO model (10-mm advancement and setback) was constructed with Mimics. Bicortical screw fixation using Ti, IN, and Mg screws was performed with 4 different geometries of fixation. With an occlusal load of 132 N on the lower first molar, the von Mises stress (VMS) distribution was calculated using ANSYS. RESULTS: The VMS distribution of Mg was more similar to that of Ti than to that of IN. In all cases, the highest VMS was concentrated on the screw at the most posterior and superior area. Stress was distributed mainly around the screw holes (cancellous bone) and the retromolar area (cortical bone). In the advancement surgery, fixation with 5 Mg screws (5A-Mg, 99.810 MPa at cortical bone) showed biomechanical stability, whereas fixation with the same number of IN screws did not (5A-IN, 109.021 MPa at cortical bone). In the setback surgery, although the maximum VMSs at cortical bone for Mg, IN, and Ti were lower than 108 MPa (yield strength of cortical bone), Mg screws showed more favorable results than IN screws because the maximum VMSs of Mg at cancellous bone were lower than those of IN. CONCLUSION: The Mg-based resorbable screw system is a promising alternative to the IN-based system.
Authors: Pascal Heye; Christoph Matissek; Clemens Seidl; Marcell Varga; Tamas Kassai; Gergö Jozsa; Thomas Krebs Journal: Children (Basel) Date: 2022-03-29