Effect of Proximal Segment Positioning on Condylar Remodeling

August 6, 2026 updated by: Bezmialem Vakif University

The Effect Of Different Proximal Segment Positioning Methods On Postoperative Condylar Remodeling in Patients Undergoing Bimaxillary Orthognathic Surgery

This study aims to evaluate postoperative condylar remodeling in patients undergoing bimaxillary orthognathic surgery by comparing two different proximal segment positioning techniques used during mandibular osteotomy. Condylar remodeling will be assessed using preoperative, immediate postoperative, and 6-month postoperative computed tomography (CT) scans together with clinical findings.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Bilateral sagittal split ramus osteotomy (BSSO), performed as part of bimaxillary orthognathic surgery, requires accurate positioning of the proximal mandibular segment to achieve postoperative skeletal stability and preserve temporomandibular joint function. During mandibular repositioning, discrepancies at the inferior border of the mandibular segments may be managed either by rotating the proximal segment to achieve inferior border alignment or by leveling the inferior border without rotating the proximal segment. The influence of these different positioning strategies on postoperative condylar remodeling has not been fully elucidated.

The aim of this study is to compare postoperative condylar remodeling between patients treated with proximal segment rotation for inferior border alignment and those treated with inferior border leveling without proximal segment rotation.

Condylar remodeling will be evaluated using computed tomography (CT) images obtained preoperatively, immediately after surgery, and at the 6-month postoperative follow-up. Radiological findings will be analyzed together with clinical outcomes to assess changes in condylar morphology and postoperative adaptation. The results of this study are expected to provide evidence regarding the effect of different proximal segment positioning methods on condylar remodeling and may contribute to optimizing surgical techniques in orthognathic surgery.

Study Type

Interventional

Enrollment (Estimated)

40

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  1. Patients with skeletal Class III dentofacial deformity scheduled to undergo bimaxillary orthognathic surgery.
  2. Age between 18 and 65 years.
  3. Patients who have completed preoperative orthodontic treatment.
  4. Patients in whom the mandibular distal segment demonstrates a maximum counterclockwise rotation of 4° after bilateral sagittal split osteotomy (BSSO) when positioned in the final planned occlusion.

Exclusion Criteria:

  1. History of temporomandibular joint surgery, orthognathic surgery, or tumor resection.
  2. Presence of facial asymmetry.
  3. Patients with cleft lip and/or palate, craniofacial syndromes, or a history of maxillofacial trauma.
  4. Patients in whom the mandibular distal segment requires more than 4° of counterclockwise rotation after BSSO to achieve the final planned position, as the amount of inferior border (basal) resection required would exceed the clinically acceptable limit.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Proximal Segment Rotation
Patients underwent mandibular osteotomy followed by repositioning of the proximal segment. Alignment of the inferior border of the proximal segment with the mandibular inferior border was achieved by rotating the proximal segment before fixation.
Procedure: Proximal Segment Rotation
During bimaxillary orthognathic surgery, after bilateral sagittal split osteotomy (BSSO), the proximal mandibular segment is rotated to achieve alignment of the inferior border of the proximal and distal mandibular segments before rigid fixation.
Experimental: Inferior Border Osteotomy Without Proximal Segment Rotation
Patients underwent mandibular osteotomy with the proximal segment maintained in its preoperative position. Alignment of the mandibular inferior border was achieved by performing an additional osteotomy at the inferior border of the proximal segment without rotating the proximal segment before fixation.
Procedure: Inferior Border Osteotomy Without Proximal Segment Rotation
During bimaxillary orthognathic surgery, after bilateral sagittal split osteotomy (BSSO), the proximal mandibular segment is maintained in its preoperative position. Alignment of the mandibular inferior border is achieved by performing an additional osteotomy at the inferior border of the proximal segment without rotating the proximal segment before rigid fixation.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Three-dimensional condylar axis angular changes
Time Frame: From enrollment to the end of treatment at 6 months
Changes in condylar axis orientation will be assessed using computed tomography (CT) by measuring the condylar axis angle in the axial, coronal, and sagittal planes relative to standardized reference planes. In the axial plane, the angle between the condylar axis and the midsagittal reference plane (MSR) will be measured. In the coronal and sagittal planes, the angle between the condylar axis and the Frankfort Horizontal Plane (FHP) will be measured. Preoperative, immediate postoperative, and 6-month postoperative measurements will be compared to evaluate postoperative condylar remodeling and positional changes.
From enrollment to the end of treatment at 6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Bezmialem Vakif University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 1, 2026

Primary Completion (Estimated)

December 15, 2026

Study Completion (Estimated)

December 28, 2026

Study Registration Dates

First Submitted

August 6, 2026

First Submitted That Met QC Criteria

August 6, 2026

First Posted (Actual)

August 11, 2026

Study Record Updates

Last Update Posted (Actual)

August 11, 2026

Last Update Submitted That Met QC Criteria

August 6, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • E.185561

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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