Stability of Two Different Designs of Patient Specific Osteosynthesis "One Piece VS Two Piece" For The Fixation of LeFort 1 Osteotomy in Maxillary Orthognathic Surgery A Randomized Clinical Trial

• Intervention Group: -

Pre-Operative Virtual planning:

After CT examinations, further processing of the DICOM files (Digital Imaging and Communications in Medicine) will be performed using the specialized DICOM image processing software and reconstructed 3D models of the skull will be made. Stone models will be scanned using an optical scanner and stereolithographic files will be imported. Registration of the STL files with the skull model will create a composite model suitable for the construction of necessary devices. These 3D models will be used to design the custom-made cutting guides and fixation devices. The final STL files will be sent to the lab to be milled/printed.

Surgical procedure:

Routine site preparation regarding L.A injections and surgical site disinfections. A maxillary vestibular incision will be made from the maxillary second premolar on one side to the contralateral tooth. The incision will be made 5 mm above the mucogingival junction to leave an adequate cuff for closure. A full thickness mucoperiosteal flap will be reflected to expose the anterior and lateral maxillary walls. Superiorly the reflection exposes the pyriform rim, lateral nasal wall and the infraorbital nerve. Moving backwards, exposure of the zygomatico maxillary buttress is done followed by the maxillary tuberosity and finally the pterygomaxillary junction. The cutting guides will then be placed on the exposed maxilla. The cutting guides will have holes designed in them corresponding to the position of the fixation screws and a slot marking the level of the level of the Le fort 1 osteotomy which will be made using a reciprocating saw. The osteotomy is initiated and the cutting guide is removed.