Skeletal Stability of Le Fort I Osteotomy Using Patient-specific Osteosynthesis Compared to Mini-plate Fixation for Patients With Dentofacial Disharmony

Study Overview
=================
Brief Summary
-----------------
The aim of the study is to evaluate the Skeletal stability of Le Fort I osteotomy using patient-specific osteosynthesis compared to Mini-plate fixation for patients with skeletal class III malocclusion.

Detailed Description
-----------------
postsurgical relapse is one of the most common observations that have been reported after fixation of Le Fort I osteotomy cases. Fixation systems with plates and screws are used in oral maxillofacial surgery for the treatment of facial fractures and orthognathic surgery cases. Although they have been used for decades and have become the standard treatment, the materials used in these systems may fail due to excess loading and other causal factors during the surgical procedure, including failure in plate adaptation and fixation to bone, material design, fabrication, and degree of purity of the plate material. In the fixation system, non-customized plates of standard size are used, and are bent to adapt them to the distances required for planning orthognathic surgeries. Therefore, mandatory use of larger plates than those programmed for use in surgeries is required so that they can be bent to enable insertion. Moreover, there are variations in the number of screws required to retain the plates to enable better fixation. The folds of non-customized plates generate stresses that are minimized when using customized plates, because these plates are fabricated individually, with predetermined sizes for each patient.

Official Title
-----------------
Skeletal Stability of Le Fort I Osteotomy Using Patient-specific Osteosynthesis Compared to Mini-plate Fixation for Patients With Dentofacial Disharmony. A Randomized Controlled Clinical Trial

Conditions
-----------------
Dentofacial Deformities

Intervention / Treatment
-----------------
* Procedure: Bimaxillary orthognathic surgery using conventional plates
* Procedure: Bimaxillary orthognathic surgery using patient specific plates


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patients with skeletal class III malocclusion planned for traditional Orthognathic Approach and requiring bimaxillary orthognathic surgeries in which there will be Le Fort I osteotomy with maxillary advancement ranging from 2mm to 5 mm in addition to mandibular setback. Patients with no signs or symptoms of active TMDs. Highly motivated patients. Exclusion Criteria: Patients who refused to be included in the research. Patients with systemic diseases that may hinder the normal healing process or render the patient not fitting for general anaesthesia. Patients with intra-bony lesions or infections that may retard the osteotomy healing.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Group I (Conventional plates)<br>Digital intermediate and final interocclusal wafer splints will be designed to guide the maxilla and mandible in the desired position using CAD software (3-matic 11.0; Materialise NV, Leuven, Belgium). The designed splints will be then exported in stereolithography (STL) file format to the additive CAM machine (FORMIGA P 110 printer; EOS e-manufacturing solutions, Munich, Germany) and manufactured in white polyamide (PA2200; EOS e-manufacturing solutions, Munich, Germany) using fused deposition modelling (FDM) technology.The splints will be cold sterilized by overnight immersion in 2% glutaraldehyde. 2.0 conventional mini plates will be used for fixation of maxilla and mandible in the new position. | Procedure: Bimaxillary orthognathic surgery using conventional plates<br>* le fort I osteotomy will carried out in the classic way guided by the classic landmarks (maxillary roots apices) as described by Wassmund. Complete separation of the maxillary segment using chisels and mallets in regular fashion. Reposition maxilla using the interocclusal wafer while mandible is gently positioned to centric relation position. Mandible is maintained in place until fixation of the maxilla with plates and screws takes place. Complete separation of the mandibular segment using chisels and mallets in regular fashion. Repositioning of mandible using the final interocclusal wafer while condylar segment is gently positioned to centric relation position. Fixation of mandibular segments with plates and/or screws in regular fashion. Incision was closed with 4-0 resorbable sutures in a continuous running fashion.<br>|
| Experimental: Group II (Patient specific plates)<br>The cutting guides will be designed on the maxilla and mandible to orient the osteotomy and mark reference holes to be used later for the repositioning/ fixation plate, using CAD software. The designed guide will be then exported in stereolithography (STL) file format to the additive CAM machine and manufactured in white polyamide using fused deposition modelling (FDM) technology. No finishing or polishing was done in order to maintain accuracy. The guides will be cold sterilized by overnight immersion in 2% glutaraldehyde. The patient-specific osteosynthesis plates will be designed to fix the maxilla and mandible in the desired position making use of the previously established reference holes. The designed plates will be exported in STL file format to be manufactured in grade 5 titanium alloy utilizing selective laser sintering (SLS) technology on an additive CAM machine. | Procedure: Bimaxillary orthognathic surgery using patient specific plates<br>* The cutting guide of the maxilla will be placed onto the exposed bony surface and manipulated to the best fit. Then, the guide will be fixed using four 2.0-mm screws to avoid any mobilization during drilling of the reference holes. Sixteen reference holes will be established using the cutting guide; eight on each side. Then, a reciprocating saw will be used to perform the planned Le Fort I osteotomy. After adequate maxillary mobilization and removal of bony interferences, the maxilla will be repositioned using the patient-specific osteosynthesis material guided by the previously established reference holes and fixed using 2.0-mm screws. Then, the mandibular cutting guide will be fixed in the same manner and bilateral sagittal split osteotomy will be carried out. After adequate mobilization, the mandible will be repositioned by the patient-specific osteosynthesis material using the reference holes made by cutting guide and fixed using 2.0-mm screws.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Skeletal relapse of Le Fort I osteotomy | Skeletal relapse will be assessed through measuring Linear deviations (DT) between the immediate postoperative (T1) and the 12 months postoperative position (T2) in Mimics 19.0 software using hard tissue reference points (A point, Anterior nasal spine, posterior nasal spine, Incisive foramen, Right side Greater palatine foramen, Left side Greater palatine foramen) in relation to three reference planes (Frankfort horizontal plane (FHP), coronal plane, and mid-facial plane (MFP)). Measurements from the reference points to the FHP indicated vertical deviation, to the coronal plane indicated anteroposterior deviation, and to the MFP indicated mediolateral deviation. measurements will be in millimeters. | Linear deviations between immediate postoperative and 12 months postoperative position | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
orthognathic surgery, virtual planning, customized titanium plates, cutting guides, CAD/CAM