Dentofacial DeformitiesNCT06897787
Effect of Proximal Segment Positioning on Postoperative Condylar Remodeling in Bimaxillary Orthognathic Surgery
A study testing manuel positioning group and mandibular basis osteotomy in people with Dentofacial Deformities and Dentofacial Anomalies [Including Malocclusion] and Other Disorders of Jaw (M26-M27), run by Bezmialem Vakif University at 1 site in Turkey (Türkiye).
Trial summary
Bimaxillary orthognathic surgery is a surgical procedure that involves simultaneous corrections to both the maxilla (upper jaw) and mandible (lower jaw). This surgery is performed to correct facial and jaw deformities, improve occlusion, and enhance facial symmetry. Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Dentofacial Deformities, Dentofacial Anomalies [Including Malocclusion] and Other Disorders of Jaw (M26-M27)
- What is being tested?
- manuel positioning group and mandibular basis osteotomy
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 30 Mar 2025to 30 Apr 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Patients planned to undergo bimaxillary orthognathic surgery with Class III skeletal deformity
- Patients aged 18-65
- Patients who have undergone preoperative orthodontic treatment
- Patients who, after mandibular distal segment sagittal split osteotomy, exhibit a maximum of 4 degrees of counterclockwise rotation when brought to the final position
Who cannot join
- Patients with a history of joint surgery, orthognathic surgery, or tumor resection
- Patients with facial asymmetry
- Patients with cleft lip and palate syndrome, craniofacial syndrome, or trauma
- Patients who, after mandibular distal segment sagittal split osteotomy, exhibit more than 4 degrees of counterclockwise rotation when brought to the final position (as the amount of base resection required in this case would exceed feasible limits).
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site
Bezmialem Vakıf Universty
Istanbul, Fatih, 34093
About this study
Official title: The Effect Of Different Proximal Segment Positioning Methods On Postoperative Condylar Remodeling in Patients Undergoing Bimaxillary Orthognathic Surgery
Bimaxillary orthognathic surgery is a surgical procedure that involves simultaneous corrections to both the maxilla (upper jaw) and mandible (lower jaw). This surgery is performed to correct facial and jaw deformities, improve occlusion, and enhance facial symmetry. The need for orthognathic surgery typically arises in cases where there is a significant discrepancy between the upper and lower jaws or severe malocclusion.
In bimaxillary orthognathic surgery, following mandibular osteotomies, the lower jaw is divided into two segments: the distal segment, which contains the teeth, and the proximal segment, which includes the condylar head. While the distal segment is positioned according to the ideal occlusion planned in collaboration with orthodontists using digital design, the management of the proximal segment varies among surgeons. Some surgeons leave the proximal segment in its original position without mobilization, whereas others reposition it through rotational movements.
This study aims to evaluate condylar remodeling by comparing these two surgical approaches in patients divided into two groups, assessing how each technique affects postoperative outcomes.
Read the detailed description
Bimaxillary orthognathic surgery is a surgical procedure that involves simultaneous correction of both the maxilla (upper jaw) and the mandible (lower jaw). This surgery is performed to correct facial and jaw deformities, improve occlusion, and enhance facial symmetry. The need for orthognathic surgery typically arises in cases where there is a discrepancy between the upper and lower jaws or significant malocclusion.
In bimaxillary orthognathic surgery, following mandibular osteotomies, the lower jaw is divided into two segments: the distal segment, which contains the teeth, and the proximal segment, which includes the condylar head. While the distal segment is positioned according to the ideal occlusion planned in collaboration with orthodontists using digital design, the management of the proximal segment varies among surgeons. Some surgeons leave the proximal segment in its original position without mobilization, whereas others reposition it through rotational movements.
This study aims to evaluate condylar remodeling by applying both surgical approaches to patients divided into two groups. The study will assess how each surgical technique affects condylar remodeling both in terms of angular and volumetric changes, determining which approach better preserves and reshapes the joint optimally. Ultimately, the findings will contribute to the future course of bimaxillary orthognathic surgeries and their benefits for patients.
Since 1990, cone-beam computed tomography (CBCT) has been effectively used in oral and maxillofacial surgery as an alternative to conventional computed tomography (CT). Compared to CT, CBCT has demonstrated advantages such as requiring a lower radiation dose, producing fewer metal artifacts, being more accessible, and offering easier usage. Due to these advantages, CBCT has been successfully utilized in oral implant applications, where a localized focus area is necessary. However, limitations such as low contrast range, restricted detector size, limited soft tissue information, increased noise due to scattered radiation, and a subsequent loss of contrast resolution, along with its inability to determine Hounsfield units (HU), restrict its use in maxillofacial applications.
Particularly in preoperative digital planning for orthognathic surgery and subsequent evaluations, it is crucial to select an appropriate HU range to segment the maxilla and mandible and accurately transfer all topographic features into the digital domain. This step forms the foundation of patient-specific virtual surgical planning, which requires the use of computed tomography (CT) for optimal execution. Studies have preferred CT as the imaging method due to its high accuracy in topographic transfer and its ability to provide precise cortical bone thickness, a critical factor for designing patient-specific guides and plates. For these reasons, we also plan to use CT imaging in our study.
- Conditions
- Dentofacial Deformities, Dentofacial Anomalies [Including Malocclusion] and Other Disorders of Jaw (M26-M27)
- Being tested
- manuel positioning group, mandibular basis osteotomy
- Keywords
- mandibular condyle, orthognathic surgery, manuel condyle positioning
- Medical subject headings
- Dentofacial Deformities
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
manuel positioning groupProcedure or surgery
As Prof. Reyneke does, mandibular base and proximal segment leveling are performed first, followed by fixation.
mandibular basis osteotomyProcedure or surgery
After the mandibular sagittal split, secure the proximal segment in its preoperative position and remove the bone piece for leveling. After that, fixation is performed.
| Study group | Role | What they receive |
|---|---|---|
| group 1: Manuel positioning group | Active comparator | This is the group in which leveling between the lower border of the proximal segment and the mandibular base is achieved through proximal segment rotation after mandibular osteotomies. Receives: Procedure: manuel positioning group |
| group 2: mandibular basis osteotomy | Experimental | This is the group in which the proximal segment is left in its preoperative position, and leveling of the mandibular base is achieved by performing an osteotomy on the lower border of the proximal segment. Receives: Procedure: mandibular basis osteotomy |
What is being measured
The primary outcome is the main question the study is designed to answer.
mandibular condyle position superimposition
During bimaxillary orthognathic surgery, proximal segment positioning devices will be used in both groups to ensure that the condylar position remains at the location determined during virtual surgical planning. These devices will be custom-designed for each patient by the researchers using the virtual surgical planning software and printed using an in-house 3D printer. These positioning devices will maintain the condyle in its initial position during mandibular fixation. Postoperative DICOM data obtained from computed tomography images will be used to superimpose the condylar positions, and the amount of displacement in three planes (x, y, z) will be measured in millimeters (mm). Additionally, condylar volume changes will be calculated in cubic centimeters (cm³) using the superimposition method, and differences between the groups will be evaluated.
Measured: 2 year
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted27 Mar 2025
- Study start30 Mar 2025
- Primary completion1 Mar 2027 (estimated)
- Study completion30 Apr 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Dentofacial DeformitiesStudies of the same condition, open and under way.
- More trials run by Bezmialem Vakif UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Bezmialem Vakif University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06897787
- Sponsor's protocol ID
- 07.03.2025-E.185561
- Status last verified
- Jun 2025
- First submitted
- 17 Mar 2025
- Last updated
- 24 Jun 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 24 Jun 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect Of Different Proximal Segment Positioning Methods On Postoperative Condylar Remodeling in Patients Undergoing Bimaxillary Orthognathic Surgery
- ClinicalTrials.gov ID
- NCT06897787
- Acronym / sponsor ID
- 07.03.2025-E.185561
- Conditions
- Dentofacial Deformities, Dentofacial Anomalies [Including Malocclusion] and Other Disorders of Jaw (M26-M27)
- Keywords
- mandibular condyle, orthognathic surgery, manuel condyle positioning
- Study type
- Interventional
- Recruitment status
- Enrolling by invitation
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- Bezmialem Vakif UniversityUniversity, hospital or other
- Study start
- 30 Mar 2025 (actual)
- Primary completion
- 1 Mar 2027 (estimated)
- Study completion
- 30 Apr 2027 (estimated)
- First posted
- 27 Mar 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Bimaxillary orthognathic surgery is a surgical procedure that involves simultaneous corrections to both the maxilla (upper jaw) and mandible (lower jaw). This surgery is performed to correct facial and jaw deformities, improve occlusion, and enhance facial symmetry. The need for orthognathic surgery typically arises in cases where there is a significant discrepancy between the upper and lower jaws or severe malocclusion.
In bimaxillary orthognathic surgery, following mandibular osteotomies, the lower jaw is divided into two segments: the distal segment, which contains the teeth, and the proximal segment, which includes the condylar head. While the distal segment is positioned according to the ideal occlusion planned in collaboration with orthodontists using digital design, the management of the proximal segment varies among surgeons. Some surgeons leave the proximal segment in its original position without mobilization, whereas others reposition it through rotational movements.
This study aims to evaluate condylar remodeling by comparing these two surgical approaches in patients divided into two groups, assessing how each technique affects postoperative outcomes.
Detailed description
Bimaxillary orthognathic surgery is a surgical procedure that involves simultaneous correction of both the maxilla (upper jaw) and the mandible (lower jaw). This surgery is performed to correct facial and jaw deformities, improve occlusion, and enhance facial symmetry. The need for orthognathic surgery typically arises in cases where there is a discrepancy between the upper and lower jaws or significant malocclusion.
In bimaxillary orthognathic surgery, following mandibular osteotomies, the lower jaw is divided into two segments: the distal segment, which contains the teeth, and the proximal segment, which includes the condylar head. While the distal segment is positioned according to the ideal occlusion planned in collaboration with orthodontists using digital design, the management of the proximal segment varies among surgeons. Some surgeons leave the proximal segment in its original position without mobilization, whereas others reposition it through rotational movements.
This study aims to evaluate condylar remodeling by applying both surgical approaches to patients divided into two groups. The study will assess how each surgical technique affects condylar remodeling both in terms of angular and volumetric changes, determining which approach better preserves and reshapes the joint optimally. Ultimately, the findings will contribute to the future course of bimaxillary orthognathic surgeries and their benefits for patients.
Since 1990, cone-beam computed tomography (CBCT) has been effectively used in oral and maxillofacial surgery as an alternative to conventional computed tomography (CT). Compared to CT, CBCT has demonstrated advantages such as requiring a lower radiation dose, producing fewer metal artifacts, being more accessible, and offering easier usage. Due to these advantages, CBCT has been successfully utilized in oral implant applications, where a localized focus area is necessary. However, limitations such as low contrast range, restricted detector size, limited soft tissue information, increased noise due to scattered radiation, and a subsequent loss of contrast resolution, along with its inability to determine Hounsfield units (HU), restrict its use in maxillofacial applications.
Particularly in preoperative digital planning for orthognathic surgery and subsequent evaluations, it is crucial to select an appropriate HU range to segment the maxilla and mandible and accurately transfer all topographic features into the digital domain. This step forms the foundation of patient-specific virtual surgical planning, which requires the use of computed tomography (CT) for optimal execution. Studies have preferred CT as the imaging method due to its high accuracy in topographic transfer and its ability to provide precise cortical bone thickness, a critical factor for designing patient-specific guides and plates. For these reasons, we also plan to use CT imaging in our study.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| group 1: Manuel positioning group | Active comparator | Procedure: manuel positioning groupThis is the group in which leveling between the lower border of the proximal segment and the mandibular base is achieved through proximal segment rotation after mandibular osteotomies. |
| group 2: mandibular basis osteotomy | Experimental | Procedure: mandibular basis osteotomyThis is the group in which the proximal segment is left in its preoperative position, and leveling of the mandibular base is achieved by performing an osteotomy on the lower border of the proximal segment. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Patients planned to undergo bimaxillary orthognathic surgery with Class III skeletal deformity
- Patients aged 18-65
- Patients who have undergone preoperative orthodontic treatment
- Patients who, after mandibular distal segment sagittal split osteotomy, exhibit a maximum of 4 degrees of counterclockwise rotation when brought to the final position
Key exclusion criteria (4 listed)
- Patients with a history of joint surgery, orthognathic surgery, or tumor resection
- Patients with facial asymmetry
- Patients with cleft lip and palate syndrome, craniofacial syndrome, or trauma
- Patients who, after mandibular distal segment sagittal split osteotomy, exhibit more than 4 degrees of counterclockwise rotation when brought to the final position (as the amount of base resection required in this case would exceed feasible limits).
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| manuel positioning groupAs Prof. Reyneke does, mandibular base and proximal segment leveling are performed first, followed by fixation. | Procedure or surgery | group 1: Manuel positioning group |
| mandibular basis osteotomyAfter the mandibular sagittal split, secure the proximal segment in its preoperative position and remove the bone piece for leveling. After that, fixation is performed. | Procedure or surgery | group 2: mandibular basis osteotomy |
Primary outcome
mandibular condyle position superimposition
Time frame: 2 year
During bimaxillary orthognathic surgery, proximal segment positioning devices will be used in both groups to ensure that the condylar position remains at the location determined during virtual surgical planning. These devices will be custom-designed for each patient by the researchers using the virtual surgical planning software and printed using an in-house 3D printer. These positioning devices will maintain the condyle in its initial position during mandibular fixation. Postoperative DICOM data obtained from computed tomography images will be used to superimpose the condylar positions, and the amount of displacement in three planes (x, y, z) will be measured in millimeters (mm). Additionally, condylar volume changes will be calculated in cubic centimeters (cm³) using the superimposition method, and differences between the groups will be evaluated.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Jun 2025.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing manuel positioning group and mandibular basis osteotomy in people with Dentofacial Deformities and Dentofacial Anomalies [Including Malocclusion] and Other Disorders of Jaw (M26-M27), run by Bezmialem Vakif University at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 24 Jun 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
mandibular condyle position superimposition (time frame: 2 year). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Jun 2025.