Biomechanical evaluation of a T-shaped miniplate fixation of a modified sagittal split ramus osteotomy with buccal step, a new technique for mandibular orthognathic surgery.
OBJECTIVE
The purpose of this study was to biomechanically evaluate the stability of a T-shaped miniplate fixation of a modified sagittal split ramus osteotomy (MSSRO) with buccal step and to compare it with single or double-parallel straight miniplates fixing a standard sagittal split ramus osteotomy (SSRO).


METHODS
Eighteen Synbone mandibular replicas were used in the study and divided into 3 groups. Standard SSRO was applied in the first and second groups, and the third group was cut for MSSRO with buccal step. After 7 mm of advancement, fixation modalities for the 3 groups included a single straight miniplate, double-parallel straight miniplates, and a T-shape miniplate, respectively. Each model was secured in a jig and subjected to vertical load on the anterior teeth.


RESULTS
The T miniplate group showed a significantly higher value for stability than the group with a single straight miniplate. There was no significant difference in stability between the T miniplate and the double-parallel straight miniplate groups.


CONCLUSIONS
For mandibular advancement surgery of 7 mm in a laboratory environment, a T-shaped miniplate used with MSSRO and buccal step as a combination significantly optimize the resistance and stability of the fixation compared with a standard SSRO fixed with a single straight miniplate.
Aymach
Zaher
Z
Department of Maxillofacial Surgery, Graduate School of Dentistry, Tohoku University, Aoba-ku, Sendai, Japan. zeimich@hotmail.com
Nei
Hitoshi
H
Kawamura
Hiroshi
H
Bell
William
W
D001696:Biomechanical Phenomena; D001732:Bite Force; D001860:Bone Plates; D003799:Dental Stress Analysis; D004867:Equipment Design; D006801:Humans; D019248:Jaw Fixation Techniques / Q000295:instrumentation*; D008334:Mandible / Q000601:surgery*; D019186:Mandibular Advancement / Q000295:instrumentation*; D008904:Miniaturization; D008953:Models, Anatomic; D003765:Models, Dental; D056948:Orthognathic Surgical Procedures / Q000295:instrumentation*; D018709:Statistics, Nonparametric