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Study Title Comparison of Maxillary Accuracy Between Virtual and Conventional Surgical Planning in Bimaxillary Orthognathic Surgery: A Randomized Controlled Trial Study Design
Type: Prospective, single-center, randomized, blinded, case-controlled trial
Location: National Hospital of Odonto-Stomatology, Ho Chi Minh City
Period: August 2023 - February 2025
Sample size: 20 patients
Ethical approval: Granted by the University of Medicine and Pharmacy at HCMC (Approval No. 647/HĐĐĐ-ĐHYD) Inclusion Criteria
Patients aged 18-30 years
Diagnosed with malocclusion requiring bimaxillary orthognathic surgery
Completed presurgical orthodontic treatment Exclusion Criteria
Cleft lip/palate, craniofacial syndromes
Deformities due to trauma, tumors, or iatrogenic causes
TMJ disorders
History of previous orthognathic surgery
Planned multipiece Le Fort I osteotomy Randomization and Blinding
All patients underwent both 2D and 3D surgical planning.
Two splints (CSP and VSP) were fabricated for each patient.
Intraoperative randomization was performed by an OR nurse.
The surgical team and data analysts were blinded to group allocation.
Groups were revealed only after data analysis. Groups
Test group (VSP): 3D virtual planning, simulation, and 3D-printed splints
Control group (CSP): 2D cephalometric planning, model surgery, conventional resin splints Surgical Procedure
All patients underwent Le Fort I and BSSO
Maxilla-first approach with fixation using 4 miniplates
Mandibular repositioning using final splint and fixed with 2 miniplates per side
All surgeries performed by a single experienced surgeon Data Collection & Measurements
CT scans before and 2 weeks after surgery
Superimposition using Invivo 7.0 software (voxel-based registration)
Measured landmark changes (A point, ANS, U1, U3, U6) in X (medial-lateral), Y (anterior-posterior), and Z (vertical) directions
Compared:
ICC used to test measurement reliability (10 patients, remeasured after 2 weeks)
Normality tested
Paired t-test/Wilcoxon for planned vs. actual
Independent t-test/Mann-Whitney for between-group comparisons
Significance set at p < 0.05
Full description
Materials and Methods Study Design This study was conducted as a prospective, single-center, randomized, and blinded case-controlled trial. The research protocol was reviewed and approved by the Ethics Committee of the University of Medicine and Pharmacy at Ho Chi Minh City (Approval No. 647/HĐĐĐ-ĐHYD). All participants were fully informed of their treatment options and provided written informed consent prior to enrollment. The study adhered to ethical guidelines for clinical research, ensuring the protection of participants' rights, safety, and confidentiality.
Study Subjects The study was carried out at the National Hospital of Odonto-Stomatology in Ho Chi Minh City between August 2023 and February 2025. Eligible participants were aged 18 to 30 years and diagnosed with malocclusion requiring bimaxillary orthognathic surgery.
Exclusion criteria included:
Randomization and Blinding Each patient underwent both two-dimensional (2D) lateral cephalometric analysis and three-dimensional (3D) virtual surgical planning preoperatively. For each case, both a conventional surgical splint and a 3D-printed splint were fabricated.
Randomization was performed intraoperatively by an operating room nurse through a simple draw to determine which splint would be used. Allocation was recorded accordingly. The surgical and research teams were blinded to group assignment, with participants identified only as "Group 1" or "Group 2." Group identities (VSP or CSP) were only disclosed after data collection and analysis were complete.
Patients were assigned to two groups:
Facebow registration and intermaxillary relationship assessment were performed, followed by mounting on a semi-adjustable articulator using the standard Frankfort horizontal plane. Final occlusion was determined by the orthodontist. Dental models were digitized using the Autoscan-DS-EX Pro (Shining 3D) scanner.
Surgical planning was initially based on clinical findings and 2D cephalometric analysis using WebCeph software. Parameters included maxillary dental midline, anteroposterior and vertical positioning of maxillary incisors, and occlusal plane canting determined by the canine and first molar reference points.
3D Simulation
A 3D virtual skull model was constructed using anatomical reference planes for consistent orientation:
Next, refinements were applied using VSP to adjust occlusal plane canting, midline deviation, yaw rotation, and anteroposterior and vertical positioning based on Vietnamese normative standards. These refined landmark positions were recorded as P3D (Planning 3D).
Comparison Between P2D and P3D Differences in landmark movements between P2D and P3D (A point, ANS, U1, U1L, U1R, U3L, U3R, U6L, U6R) were analyzed to assess the discrepancies between 2D and 3D planning methods.
Group Allocation and Splint Fabrication
After determining the final maxillary and mandibular positions, surgical splints were fabricated as follows:
Surgical Procedures All surgeries were performed by the same experienced maxillofacial surgeon using a standardized maxilla-first approach.
Postoperative Skeletal Accuracy Analysis Two weeks post-surgery, all patients underwent CT imaging in occlusion with the final splint and before initiation of postoperative orthodontic treatment.
Pre- and postoperative scans were superimposed using voxel-based registration (Invivo 7.0, Anatomage, CA), aligned to non-surgical cranial reference areas using the same reference planes:
Surgical accuracy was evaluated through:
Statistical Analysis
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20 participants in 2 patient groups
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Data sourced from clinicaltrials.gov
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