Tooth and Bone-borne Cutting/Repositioning Guide and Patient-specific Implant(PSI) (PSI)

A Prospective, Randomized, Controlled, Single-blind Study on the Hybrid Tooth and Bone-supported Cutting and Repositioning Guides Versus Computer-aided Design/Computer-aided Manufactured Splints in "Surgery-first" Orthognathic Surgery

Dentofacial deformity refers to a group of disorders characterized by malocclusion and facial asymmetry resulting from developmental abnormalities of the maxilla and mandible, which cause morphological and positional anomalies of the jaws. Compared with the traditional orthodontics-orthognathic surgery-orthodontics treatment protocol, the surgery-first approach has witnessed a continuous expansion of its clinical application scope. Nevertheless, academic controversies persist regarding its indication boundaries, postoperative jaw stability, and adaptive changes of the temporomandibular joint.

In orthognathic surgery, computer-aided design/computer-aided manufacturing (CAD/CAM) surgical guides indirectly determine the three-dimensional spatial positions of the maxilla and mandible through occlusal relationships. The tooth-bone dual-supported osteotomy and positioning guide combined with pre-bent patient-specific implants (PSIs) forms a novel surgical guide system that enables independent and direct positioning of the maxilla. Theoretically, this system can eliminate errors derived from mandibular positional instability and thereby improve surgical accuracy. However, comparative studies investigating the clinical application of these two types of guides in surgery-first orthognathic surgery are still lacking.

This prospective, randomized, controlled, single-blind clinical study aimed to explore the clinical value of PSIs and conventional CAD/CAM guides in surgery-first orthognathic surgery, with primary outcomes focusing on surgical accuracy, postoperative jaw stability, and temporomandibular joint alterations. The findings will provide evidence-based medical support for the expanded application of this novel technique in precision orthognathic surgery.

Study Overview

• Status: Not yet recruiting
• Conditions: Orthognathic Surgery; CAD/CAM; Patient Specific Implant; Surgery-first
• Intervention / Treatment: Procedure: bimaxillary surgery(Lefort I and SSRO)

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Xiaoshuang Guo, M.D.; Phone Number: +86 13121234163; Email: gxsinjnu@126.com
• Study Contact Backup: Name: Xiaolei Jin, M.D.; Email: zxyy16jxl@163.com

Study Locations

• China
  • Beijing, China
    • Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College
    • Contact: Xiaoshuang Guo, M.D.; Phone Number: +86 13121234163; Email: gxsinjnu@126.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Age ranged from 18 to 40 years old.
2. Patients were diagnosed with dentofacial deformity and received treatment at the Plastic Surgery Hospital, Chinese Academy of Medical Sciences. The diagnosis was confirmed via comprehensive evaluation by two senior attending plastic surgeons.
3. Patients were scheduled for bimaxillary orthognathic surgery, with optional adjunctive procedures including maxillary and mandibular subapical osteotomy and genioplasty.
4. Patients were indicated for the surgery-first approach based on joint assessment by craniomaxillofacial surgeons and orthodontists. Orthodontists confirmed that satisfactory occlusal relationships could be achieved through postoperative orthodontic treatment. Preoperative dental conditions met the following requirements: no or mild anterior dental crowding, flat or shallow Spee's curve, slight incisor inclination, harmonious maxillary and mandibular dental arches, and at least three stable occlusal contacts under transitional occlusion.
5. Patients agreed to complete follow-up examinations and provided signed informed consent.

Exclusion Criteria:

1. Patients who refused to participate in the present study.
2. Presence of comorbidities that may increase surgical risks or impair surgical outcomes, as assessed by two senior plastic surgeons, including but not limited to hypertension, diabetes, immune thrombocytopenic purpura, and hemoglobin (Hb) level ≤ 100 g/L.
3. Presence of body dysmorphic disorder, a history of psychiatric disorders, or excessively demanding patients with unrealistic treatment expectations.
4. Presence of facial skeletal tumors.
5. Patients who required revision surgery after previous orthognathic procedures.
6. Cases judged unable to achieve stable occlusal relationships through postoperative orthodontic treatment following joint evaluation by craniomaxillofacial surgeons and orthodontists, including patients with severe dental crowding, maxillomandibular arch width discrepancy, temporomandibular joint disorders, or periodontal diseases.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: PSI group; Tooth-bone borne osteotomy and repositioning guides combined with patient-specific implants constitute the PSI group for short. Preoperative craniomaxillofacial computed tomography (CT) data of patients were imported for three-dimensional reconstruction. Surgical plans, including genioplasty procedures, were collaboratively formulated by surgeons and orthodontists with full consideration of patients' personal preferences. Custom tooth-bone dual-supported osteotomy and positioning guides for both the maxilla and mandible were digitally designed and subsequently fabricated. A partial skull model was printed preoperatively, on which custom titanium plates were pre-bent in advance in strict accordance with the established surgical protocol.	Procedure: bimaxillary surgery(Lefort I and SSRO); All patients underwent surgery-first bimaxillary orthognathic surgery, with concomitant optional procedures including maxillary and mandibular subapical osteotomy and genioplasty.
Active Comparator: CAD/CAM group; Patients' preoperative craniomaxillofacial computed tomography (CT) data were imported for three-dimensional (3D) reconstruction. Surgeons and orthodontists collaboratively formulated individualized surgical plans based on patients' preferences, including genioplasty procedures, followed by the design and fabrication of CAD/CAM intermediate and final surgical guides.	Procedure: bimaxillary surgery(Lefort I and SSRO); All patients underwent surgery-first bimaxillary orthognathic surgery, with concomitant optional procedures including maxillary and mandibular subapical osteotomy and genioplasty.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Linear deviation	Following the superimposition of preoperative virtual surgical planning models and postoperative actual craniomaxillofacial computed tomography (CT) datasets, manual registration was performed based on anatomical landmarks including the nasion, foramen magnum, infraorbital point, zygomatic bone, and zygomatic arch. Linear deviations of the A-point, B-point, canine teeth, and first molars relative to the Frankfort horizontal plane, facial midsagittal plane, and coronal plane were measured and recorded.	7 days and 1 year

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Angular deviation	Following the superimposition of preoperative virtual surgical planning models and postoperative actual craniomaxillofacial computed tomography (CT) datasets, manual registration was performed based on anatomical landmarks including the nasion, foramen magnum, infraorbital point, zygomatic bone, and zygomatic arch. Angular deviations of the A-point, B-point, canine teeth, and first molars relative to the Frankfort horizontal plane, facial midsagittal plane, and coronal plane were measured and recorded.	7 days and 1 year
Soft tissue change	Soft tissue changes were evaluated based on three-dimensional facial scan data acquired using a 3dMD system. Following the superimposition of preoperative virtual surgical planning models and postoperative actual facial scan datasets, changes in soft tissue landmarks were assessed, including the nasal base, lips, nose, etc.	1 year
satisfatory questionnaire		1 year

Collaborators and Investigators

• Sponsor: Peking Union Medical College
• Collaborators: Beijing Municipal Health Commission
• Investigators: Study Director: Guodong Song, Chinese Academy of Medical Sciences, Peking Union Medical College, Plastic Surgery Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): June 8, 2026
• Primary Completion (Estimated): June 8, 2028
• Study Completion (Estimated): December 31, 2028

Study Registration Dates

• First Submitted: May 28, 2026
• First Submitted That Met QC Criteria: June 3, 2026
• First Posted (Actual): June 8, 2026

Study Record Updates

• Last Update Posted (Actual): June 8, 2026
• Last Update Submitted That Met QC Criteria: June 3, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: 2026-4-4043

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Raw data of linear/angular deviation, soft tissue change, and questionnaire
• IPD Sharing Time Frame: Date of public release: The day of online publication of the article (expected December 2029)
• IPD Sharing Access Criteria: The raw data will be published as supplementary materials alongside the full text on the official platform of the target journal, and available for free download and access by readers.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No