Maxillary Transverse DeficiencySARME-TBA/HANCT07849855
Tooth-Borne (TBA) Versus Hybrid Expanders (HA) in Surgically Assisted Rapid Maxillary Expansion (SARME)
A study testing Tooth-Borne Maxillary Expansion Appliance and Hybrid Tooth-Bone-Borne Maxillary Expansion Appliance in people with Maxillary Transverse Deficiency, run by Aalborg University Hospital at 2 sites in 2 countries.
Trial summary
This randomized clinical trial will compare two types of expansion appliances used with surgically assisted rapid maxillary expansion (SARME) in adults with a narrow upper jaw. SARME is a surgical and orthodontic treatment used to widen the upper jaw when orthodontic expansion alone is not sufficient. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Maxillary Transverse Deficiency
- What is being tested?
- Tooth-Borne Maxillary Expansion Appliance and Hybrid Tooth-Bone-Borne Maxillary Expansion Appliance
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 32 participants
- Where
- 2 sitesin 2 countries
- Study dates
- Jan 2027to Dec 2031
- 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 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Moderate or severe maxillary transverse deficiency (MTD).
- Healthy adults aged 18 years or older.
- Completed craniofacial growth.
- Presence of the maxillary first premolars and first molars.
- Healthy periodontal status.
Who cannot join
- Previous surgical treatment of facial trauma or dentofacial deformities.
- Systemic disease, medication, genetic disease, or developmental condition expected to affect craniofacial morphology, bone turnover, or healing.
- Pregnancy.
- Inability to understand the study information or provide written informed consent.
Trial locations and contacts
2 sites in 2 countries. Contact the study team or a site near you to ask about taking part.
2 sites in 2 countries
Denmark1 site
Department of Oral and Maxillofacial Surgery, Aalborg University Hospital
Aalborg, 9000
Thomas Starch-Jensen, Professor, +4523266370, thomas.jensen@rn.dk
Hanna Hejlesen, Head of department, +45 28519770, hanna.hejlesen@rn.dk
Sweden1 site
Skåne University Hospital
Lund, Skåne County, 22242
Martin Bengtsson, Associated professor, 004646171169, Martin.N.Bengtsson@skane.se
About this study
Official title: Surgically Assisted Rapid Maxillary Expansion (SARME) With Tooth-Borne Appliance Compared With Hybrid Appliance: A Randomised Controlled Trial Assessing Clinical, Radiographic, and Patient-Reported Outcome Measures
This randomized clinical trial will compare two types of expansion appliances used with surgically assisted rapid maxillary expansion (SARME) in adults with a narrow upper jaw. SARME is a surgical and orthodontic treatment used to widen the upper jaw when orthodontic expansion alone is not sufficient. The study will investigate whether a tooth-borne appliance, which is supported by the teeth, and a hybrid appliance, which is supported by both the teeth and two small screws placed in the palate, produce different treatment outcomes.
A total of 32 adults scheduled for SARME at Aalborg University Hospital in Denmark and Lund University Hospital in Sweden will be randomly assigned to treatment with either the tooth-borne appliance or the hybrid appliance. Participants will be examined before surgery, after completion of the expansion phase, and six months after completion of expansion. Assessments will include cone-beam computed tomography (CBCT), digital dental scans, facial imaging, periodontal examinations, recording of complications, and questionnaires about pain, recovery, oral health-related quality of life, general quality of life, and treatment experience.
The main outcome of the study is skeletal relapse, meaning how much of the widening of the upper jaw is lost between the end of expansion and the six-month follow-up. Other outcomes include the amount of skeletal and dental expansion, tooth tipping, changes in the supporting bone and gums around the teeth, facial soft-tissue changes, complications, recovery, and patient-reported quality of life. The study aims to determine whether one appliance provides better stability or fewer unwanted effects and thereby improve future treatment recommendations for adults undergoing SARME.
Read the detailed description
Maxillary transverse deficiency in skeletally mature patients may require surgically assisted rapid maxillary expansion (SARME) when the transverse discrepancy cannot be predictably corrected by orthodontic expansion alone. Tooth-borne appliances (TBA) have traditionally been used for SARME; however, transmission of expansion forces through the teeth may contribute to dental tipping, bending of the alveolar process, periodontal effects, and subsequent dental or skeletal relapse. Hybrid appliances (HA) combine dental anchorage with skeletal anchorage through palatal mini-implants, thereby distributing part of the expansion force directly to the maxillary bone. This may potentially improve skeletal stability and reduce unwanted dentoalveolar effects. However, comparative randomized evidence using standardized three-dimensional assessments and patient-reported outcomes remains limited.
This is a two-centre, two-arm, parallel-group randomized controlled trial conducted at the Departments of Oral and Maxillofacial Surgery at Aalborg University Hospital, Denmark, and Lund University Hospital, Sweden. Thirty-two adults scheduled for SARME will be randomized in a 1:1 ratio to treatment with either TBA or HA. Computer-generated block randomization will be stratified by study centre, with allocation concealed using sequentially numbered sealed envelopes. The surgical procedure, postoperative distraction protocol, and consolidation period will be standardized between the treatment groups and study centres.
Study assessments will be performed at baseline before surgery (T0), at the end of the distraction phase (T1), and six months after completion of expansion following the consolidation period (T2). The study uses a multimodal three-dimensional assessment strategy incorporating cone-beam computed tomography, digital intraoral models, standardized three-dimensional facial stereophotography, periodontal examination, complication registration, and validated self-administered patient-reported outcome measures.
The study is designed to determine whether partial skeletal anchorage with a hybrid appliance produces clinically meaningful differences in transverse skeletal stability compared with conventional tooth-borne anchorage. The investigation will also provide a comprehensive assessment of dentoalveolar, periodontal, facial soft-tissue, complication-related, recovery-related, and patient-reported effects associated with the two appliance concepts.
Measurements will be performed using coded datasets and standardized measurement protocols. The primary statistical analysis will follow the intention-to-treat principle. Repeated measurements will be analysed using linear mixed-effects models accounting for treatment group, time, and repeated observations within participants. Statistical analyses will be performed without knowledge of treatment allocation where feasible.
- Conditions
- Maxillary Transverse Deficiency
- Being tested
- Tooth-Borne Maxillary Expansion Appliance, Hybrid Tooth-Bone-Borne Maxillary Expansion Appliance
- Keywords
- Surgically Assisted Rapid Maxillary Expansion, SARME, Surgically Assisted Rapid Palatal Expansion, SARPE, Tooth-Borne Appliance, Hybrid Appliance, Skeletal Anchorage, Maxillary Expansion, Skeletal Relapse, Dentoalveolar Expansion, Cone-Beam Computed Tomography, CBCT
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Tooth-Borne Maxillary Expansion ApplianceDevice
Also called Tooth-Borne Appliance, TBA
A CAD/CAM-fabricated tooth-borne maxillary expansion appliance used during surgically assisted rapid maxillary expansion (SARME). The appliance consists of four printed metal bands cemented to the maxillary first premolars and first molars and connected to a palatal expansion mechanism. Anchorage is provided exclusively by the teeth, with no palatal mini-implants. The appliance is cemented before surgery. Following a postoperative latency period of 5-7 days, the appliance is activated at approximately 0.5 mm per day until the planned expansion or clinical overcorrection is achieved. The appliance is subsequently maintained passively during the six-month consolidation period.
Hybrid Tooth-Bone-Borne Maxillary Expansion ApplianceDevice
Also called Hybrid Appliance, HA
A CAD/CAM-fabricated hybrid tooth-bone-borne maxillary expansion appliance used during surgically assisted rapid maxillary expansion (SARME). The appliance consists of four printed metal bands on the maxillary first premolars and first molars connected to a palatal expansion mechanism. In addition to dental anchorage, skeletal anchorage is provided by two palatal mini-implants (BENEfit® DIRECT screws, 2.0 mm diameter and 9 mm length) inserted immediately before surgery and connected to the expander. Following a postoperative latency period of 5-7 days, the appliance is activated at approximately 0.5 mm per day until the planned expansion or clinical overcorrection is achieved, followed by a six-month passive consolidation period.
| Study group | Role | What they receive |
|---|---|---|
| Tooth-Borne Appliance (TBA) | Active comparator | Participants allocated to this arm will undergo surgically assisted rapid maxillary expansion (SARME) using a tooth-borne appliance (TBA). The computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated appliance consists of four printed metal bands cemented to the maxillary first premolars and first molars and connected to a palatal expansion mechanism. No palatal mini-implants are used. The appliance is cemented before surgery. Following SARME, expansion is initiated after a latency period of 5-7 days at approximately 0.5 mm/day until the planned expansion or overcorrection is achieved. The appliance is then maintained passively during a six-month consolidation period. Receives: Device: Tooth-Borne Maxillary Expansion Appliance |
| Hybrid Appliance (HA) | Experimental | Participants allocated to this arm will undergo surgically assisted rapid maxillary expansion (SARME) using a hybrid appliance (HA). The appliance uses the same CAD/CAM design as the tooth-borne appliance, with four printed metal bands on the maxillary first premolars and first molars connected to a palatal expansion mechanism. In addition, skeletal anchorage is provided by two palatal mini-implants (BENEfit® DIRECT screws, 2.0 mm diameter, 9 mm length), inserted immediately before surgery under general anaesthesia and connected to the expander. Following SARME, expansion is initiated after a latency period of 5-7 days at approximately 0.5 mm/day until the planned expansion or overcorrection is achieved. The appliance is then maintained passively during a six-month consolidation period. Receives: Device: Hybrid Tooth-Bone-Borne Maxillary Expansion Appliance |
What is being measured
The primary outcome is the main question the study is designed to answer.
Transverse Skeletal Relapse in External Maxillary Width
Transverse skeletal relapse will be assessed as the reduction in external maxillary width (EMW) from the end of the distraction phase (T1) to the six-month follow-up (T2). EMW will be measured in millimetres on CBCT images at the maxillary first premolar and first molar levels, using the hard palate as the skeletal reference. Skeletal relapse will be calculated as the T1 EMW minus the T2 EMW; a larger positive value indicates greater skeletal relapse.
Measured: From the end of the distraction phase to 6 months after completion of expansion
Secondary outcomes (17)
Change in External Maxillary Width During Expansion
Change in external maxillary width (EMW) from baseline (T0) to the end of the distraction phase (T1). EMW will be measured in millimetres on CBCT images at the maxillary first premolar and first molar levels, using the hard palate as the skeletal reference.
Measured: From baseline before surgery to the end of the distraction phase, approximately 15-30 days after surgery
Change in Maxillary Dental Arch Width
Maxillary transverse dental width will be measured in millimetres using digital dental models and/or CBCT-derived dental landmarks. Measurements include intercanine width (cusp tip to cusp tip), interpremolar width at the first premolars (buccal cusp tip to buccal cusp tip), and intermolar width at the first molars (mesiobuccal cusp tip to mesiobuccal cusp tip). Changes between T0, T1, and T2 will be calculated to assess expansion and subsequent dental relapse.
Measured: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Maxillary Tooth Inclination
Change in inclination of the maxillary canines, first premolars, and first molars will be measured in degrees on standardized coronal CBCT images. Tooth inclination will be determined using predefined crown and root landmarks, and angular changes between study timepoints will be calculated.
Measured: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Plaque Index
Periodontal plaque accumulation will be assessed using the Plaque Index according to the standardized periodontal examination protocol. Measurements will be obtained at predefined sites around selected maxillary teeth, with corresponding mandibular teeth assessed as controls.
Measured: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Gingival Index
Gingival inflammation will be assessed using the Gingival Index according to the standardized periodontal examination protocol at predefined sites around selected maxillary teeth, with corresponding mandibular teeth assessed as controls.
Measured: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Periodontal Probing Pocket Depth
Probing pocket depth will be measured in millimetres at six periodontal sites per selected tooth: mesiobuccal, mid-buccal, distobuccal, mesiolingual, mid-lingual, and distolingual. Measurements will be performed at selected maxillary teeth with corresponding mandibular teeth serving as controls.
Measured: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Clinical Attachment Level
Clinical attachment level will be measured in millimetres at standardized periodontal sites around selected maxillary teeth, with corresponding mandibular teeth assessed as controls.
Measured: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Buccal Alveolar Bone Thickness and Height
Buccal alveolar bone thickness and height around the teeth supporting the expansion appliance will be assessed in millimetres using standardized CBCT measurements. Changes between T0, T1, and T2 will be used to assess alveolar bone effects associated with the two expansion appliances.
Measured: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Three-Dimensional Facial Soft-Tissue Measurements
Standardized three-dimensional stereophotogrammetry will be used to assess facial soft-tissue changes. Prespecified measurements include nasal base width, alar base width, nasal tip protrusion, paranasal soft-tissue changes, upper-lip region changes, facial asymmetry, and regional surface displacement. Changes between T0, T1, and T2 will be assessed using reconstructed 3D facial models.
Measured: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Incidence of Surgical and Appliance-Related Complications
The number and type of intraoperative, postoperative, and appliance-related complications will be recorded prospectively in the case report form. Events include bleeding, infection, wound dehiscence, neurosensory disturbance, asymmetric or inadequate expansion, appliance loosening or fracture, cement or band failure, expansion screw malfunction, soft-tissue irritation or ulceration, and miniscrew-related complications in the hybrid appliance group.
Measured: From surgery through 6 months after completion of expansion
Change in Oral Health Impact Profile-14 (OHIP-14) Score
Oral health-related quality of life will be assessed using the 14-item Oral Health Impact Profile (OHIP-14). The total score ranges from 0 to 56, with higher scores indicating poorer oral health-related quality of life.
Measured: Baseline before surgery, one week after surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Short Form-36 Health Survey (SF-36) Scores
General health-related quality of life will be assessed using the 36-item SF-36 questionnaire. The instrument evaluates physical functioning, physical health limitations, emotional problems, energy/fatigue, emotional well-being, social functioning, bodily pain, and general health. Scores are transformed to a 0-100 scale, with higher scores indicating better health status.
Measured: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Postoperative Pain Intensity Assessed by Visual Analogue Scale
Postoperative pain intensity will be recorded using a self-administered pain diary and a 100-mm visual analogue scale (VAS), where 0 mm represents no pain and 100 mm represents the worst tolerable pain. Pain will be recorded immediately before and one hour after analgesic intake. Analgesic consumption, including additional analgesic use, will also be documented.
Measured: During the first 15 postoperative days
Quality of Recovery-15 (QoR-15) Score
Early postoperative recovery will be assessed using the validated 15-item Quality of Recovery questionnaire (QoR-15), covering pain, physical comfort, physical independence, emotional state, and psychological support. The total score ranges from 0 to 150, with higher scores indicating better postoperative recovery.
Measured: Postoperative day 1 and postoperative day 7
Patient-Reported Recovery After SARME
Patient perception of recovery will be assessed using a self-administered recovery questionnaire. Prespecified domains include duration of pain, sick leave, effects on work and usual activities, physical and social activity, eating and chewing ability, dietary changes, speech, sleep, quality of life, and treatment satisfaction. Responses include yes/no items, Likert-type responses, visual analogue scales, and number of affected days.
Measured: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Clinical Nasal Deviation
Clinical nasal deviation will be assessed from standardized frontal facial photographs. Photographs obtained at T1 and T2 will be superimposed on the baseline T0 photograph after standardization of magnification. Nasal deviation will be quantified as the angular change in the columella/facial midline reference relative to the reference line between the medial palpebral commissures. Greater angular change indicates greater deviation from the baseline nasal position.
Measured: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Radiographic Nasal Septum Deviation
Radiographic nasal septum deviation will be assessed using standardized coronal CBCT images. Images will be compared by superimposing T1 and T2 images with the baseline T0 image, with standardized magnification and orientation. Changes will be assessed for T0 to T1, T0 to T2, and T1 to T2 to evaluate whether maxillary expansion is associated with changes in nasal septum position.
Measured: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Sep 2026
- Study startJan 2027 (estimated)
- Primary completionDec 2031 (estimated)
- Study completionDec 2031 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Maxillary Transverse DeficiencyStudies of the same condition, open and under way.
- More trials run by Aalborg University HospitalThe 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
- Model description
- Two-arm, parallel-group randomized controlled trial with 1:1 allocation to either a tooth-borne appliance (TBA) or a hybrid appliance (HA). Randomization is stratified by study centre using computer-generated block randomization.
- Masking
- None (open label)
- Enrolment
- 32 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Aalborg University Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- Lund University Hospital
- Responsible party
- Principal investigator, Osman Khachab, Aalborg University Hospital
- Investigators
- Thomas Starch-Jensen, Professor, Study director, Aalborg University HospitalHanna Hejlesen, PhD, Head of department, Study chair, Aalborg University HospitalMartin Bengtsson, Associate Professor, Study chair, Skane University Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07849855
- Sponsor's protocol ID
- SARME-AAL-2026
- Acronym
- SARME-TBA/HA
- Status last verified
- Sep 2026
- First submitted
- 16 Sep 2026
- Last updated
- 30 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be made publicly available because the study involves sensitive clinical and radiographic data collected at two hospital sites and will be handled in accordance with applicable data-protection requirements and the approved study protocol. Study results will be reported in aggregated or appropriately anonymized form in scientific publications and presentations.
Study at a glance
From the registry record, last updated by the sponsor on 30 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Surgically Assisted Rapid Maxillary Expansion (SARME) With Tooth-Borne Appliance Compared With Hybrid Appliance: A Randomised Controlled Trial Assessing Clinical, Radiographic, and Patient-Reported Outcome Measures
- ClinicalTrials.gov ID
- NCT07849855
- Acronym / sponsor ID
- SARME-TBA/HA / SARME-AAL-2026
- Conditions
- Maxillary Transverse Deficiency
- Keywords
- Surgically Assisted Rapid Maxillary Expansion, SARME, Surgically Assisted Rapid Palatal Expansion, SARPE, Tooth-Borne Appliance, Hybrid Appliance, Skeletal Anchorage, Maxillary Expansion
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 32 participants (estimated)
- Lead sponsor
- Aalborg University HospitalUniversity, hospital or other
- Collaborators
- Lund University Hospital
- Study start
- Jan 2027 (estimated)
- Primary completion
- Dec 2031 (estimated)
- Study completion
- Dec 2031 (estimated)
- First posted
- 30 Sep 2026 (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.
This randomized clinical trial will compare two types of expansion appliances used with surgically assisted rapid maxillary expansion (SARME) in adults with a narrow upper jaw. SARME is a surgical and orthodontic treatment used to widen the upper jaw when orthodontic expansion alone is not sufficient. The study will investigate whether a tooth-borne appliance, which is supported by the teeth, and a hybrid appliance, which is supported by both the teeth and two small screws placed in the palate, produce different treatment outcomes.
A total of 32 adults scheduled for SARME at Aalborg University Hospital in Denmark and Lund University Hospital in Sweden will be randomly assigned to treatment with either the tooth-borne appliance or the hybrid appliance. Participants will be examined before surgery, after completion of the expansion phase, and six months after completion of expansion. Assessments will include cone-beam computed tomography (CBCT), digital dental scans, facial imaging, periodontal examinations, recording of complications, and questionnaires about pain, recovery, oral health-related quality of life, general quality of life, and treatment experience.
The main outcome of the study is skeletal relapse, meaning how much of the widening of the upper jaw is lost between the end of expansion and the six-month follow-up. Other outcomes include the amount of skeletal and dental expansion, tooth tipping, changes in the supporting bone and gums around the teeth, facial soft-tissue changes, complications, recovery, and patient-reported quality of life. The study aims to determine whether one appliance provides better stability or fewer unwanted effects and thereby improve future treatment recommendations for adults undergoing SARME.
Detailed description
Maxillary transverse deficiency in skeletally mature patients may require surgically assisted rapid maxillary expansion (SARME) when the transverse discrepancy cannot be predictably corrected by orthodontic expansion alone. Tooth-borne appliances (TBA) have traditionally been used for SARME; however, transmission of expansion forces through the teeth may contribute to dental tipping, bending of the alveolar process, periodontal effects, and subsequent dental or skeletal relapse. Hybrid appliances (HA) combine dental anchorage with skeletal anchorage through palatal mini-implants, thereby distributing part of the expansion force directly to the maxillary bone. This may potentially improve skeletal stability and reduce unwanted dentoalveolar effects. However, comparative randomized evidence using standardized three-dimensional assessments and patient-reported outcomes remains limited.
This is a two-centre, two-arm, parallel-group randomized controlled trial conducted at the Departments of Oral and Maxillofacial Surgery at Aalborg University Hospital, Denmark, and Lund University Hospital, Sweden. Thirty-two adults scheduled for SARME will be randomized in a 1:1 ratio to treatment with either TBA or HA. Computer-generated block randomization will be stratified by study centre, with allocation concealed using sequentially numbered sealed envelopes. The surgical procedure, postoperative distraction protocol, and consolidation period will be standardized between the treatment groups and study centres.
Study assessments will be performed at baseline before surgery (T0), at the end of the distraction phase (T1), and six months after completion of expansion following the consolidation period (T2). The study uses a multimodal three-dimensional assessment strategy incorporating cone-beam computed tomography, digital intraoral models, standardized three-dimensional facial stereophotography, periodontal examination, complication registration, and validated self-administered patient-reported outcome measures.
The study is designed to determine whether partial skeletal anchorage with a hybrid appliance produces clinically meaningful differences in transverse skeletal stability compared with conventional tooth-borne anchorage. The investigation will also provide a comprehensive assessment of dentoalveolar, periodontal, facial soft-tissue, complication-related, recovery-related, and patient-reported effects associated with the two appliance concepts.
Measurements will be performed using coded datasets and standardized measurement protocols. The primary statistical analysis will follow the intention-to-treat principle. Repeated measurements will be analysed using linear mixed-effects models accounting for treatment group, time, and repeated observations within participants. Statistical analyses will be performed without knowledge of treatment allocation where feasible.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Two-arm, parallel-group randomized controlled trial with 1:1 allocation to either a tooth-borne appliance (TBA) or a hybrid appliance (HA). Randomization is stratified by study centre using computer-generated block randomization.
| Arm | Type | Receives |
|---|---|---|
| Tooth-Borne Appliance (TBA) | Active comparator | Device: Tooth-Borne Maxillary Expansion ApplianceParticipants allocated to this arm will undergo surgically assisted rapid maxillary expansion (SARME) using a tooth-borne appliance (TBA). The computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated appliance consists of four printed metal bands cemented to the maxillary first premolars and first molars and connected to a palatal expansion mechanism. No palatal mini-implants are used. The appliance is cemented before surgery. Following SARME, expansion is initiated after a latency period of 5-7 days at approximately 0.5 mm/day until the planned expansion or overcorrection is achieved. The appliance is then maintained passively during a six-month consolidation period. |
| Hybrid Appliance (HA) | Experimental | Device: Hybrid Tooth-Bone-Borne Maxillary Expansion ApplianceParticipants allocated to this arm will undergo surgically assisted rapid maxillary expansion (SARME) using a hybrid appliance (HA). The appliance uses the same CAD/CAM design as the tooth-borne appliance, with four printed metal bands on the maxillary first premolars and first molars connected to a palatal expansion mechanism. In addition, skeletal anchorage is provided by two palatal mini-implants (BENEfit® DIRECT screws, 2.0 mm diameter, 9 mm length), inserted immediately before surgery under general anaesthesia and connected to the expander. Following SARME, expansion is initiated after a latency period of 5-7 days at approximately 0.5 mm/day until the planned expansion or overcorrection is achieved. The appliance is then maintained passively during a six-month consolidation period. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Moderate or severe maxillary transverse deficiency (MTD).
- Healthy adults aged 18 years or older.
- Completed craniofacial growth.
- Presence of the maxillary first premolars and first molars.
- Healthy periodontal status.
Key exclusion criteria (4 listed)
- Previous surgical treatment of facial trauma or dentofacial deformities.
- Systemic disease, medication, genetic disease, or developmental condition expected to affect craniofacial morphology, bone turnover, or healing.
- Pregnancy.
- Inability to understand the study information or provide written informed consent.
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 |
|---|---|---|
| Tooth-Borne Maxillary Expansion ApplianceAlso: Tooth-Borne Appliance, TBAA CAD/CAM-fabricated tooth-borne maxillary expansion appliance used during surgically assisted rapid maxillary expansion (SARME). The appliance consists of four printed metal bands cemented to the maxillary first premolars and first molars and connected to a palatal expansion mechanism. Anchorage is provided exclusively by the teeth, with no palatal mini-implants. The appliance is cemented before surgery. Following a postoperative latency period of 5-7 days, the appliance is activated at approximately 0.5 mm per day until the planned expansion or clinical overcorrection is achieved. The appliance is subsequently maintained passively during the six-month consolidation period. | Device | Tooth-Borne Appliance (TBA) |
| Hybrid Tooth-Bone-Borne Maxillary Expansion ApplianceAlso: Hybrid Appliance, HAA CAD/CAM-fabricated hybrid tooth-bone-borne maxillary expansion appliance used during surgically assisted rapid maxillary expansion (SARME). The appliance consists of four printed metal bands on the maxillary first premolars and first molars connected to a palatal expansion mechanism. In addition to dental anchorage, skeletal anchorage is provided by two palatal mini-implants (BENEfit® DIRECT screws, 2.0 mm diameter and 9 mm length) inserted immediately before surgery and connected to the expander. Following a postoperative latency period of 5-7 days, the appliance is activated at approximately 0.5 mm per day until the planned expansion or clinical overcorrection is achieved, followed by a six-month passive consolidation period. | Device | Hybrid Appliance (HA) |
Primary outcome
Transverse Skeletal Relapse in External Maxillary Width
Time frame: From the end of the distraction phase to 6 months after completion of expansion
Transverse skeletal relapse will be assessed as the reduction in external maxillary width (EMW) from the end of the distraction phase (T1) to the six-month follow-up (T2). EMW will be measured in millimetres on CBCT images at the maxillary first premolar and first molar levels, using the hard palate as the skeletal reference. Skeletal relapse will be calculated as the T1 EMW minus the T2 EMW; a larger positive value indicates greater skeletal relapse.
17 secondary outcomes
Change in External Maxillary Width During Expansion
Time frame: From baseline before surgery to the end of the distraction phase, approximately 15-30 days after surgery
Change in Maxillary Dental Arch Width
Time frame: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Maxillary Tooth Inclination
Time frame: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Plaque Index
Time frame: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Gingival Index
Time frame: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Periodontal Probing Pocket Depth
Time frame: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Clinical Attachment Level
Time frame: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Buccal Alveolar Bone Thickness and Height
Time frame: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Three-Dimensional Facial Soft-Tissue Measurements
Time frame: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Incidence of Surgical and Appliance-Related Complications
Time frame: From surgery through 6 months after completion of expansion
Change in Oral Health Impact Profile-14 (OHIP-14) Score
Time frame: Baseline before surgery, one week after surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Short Form-36 Health Survey (SF-36) Scores
Time frame: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Postoperative Pain Intensity Assessed by Visual Analogue Scale
Time frame: During the first 15 postoperative days
Quality of Recovery-15 (QoR-15) Score
Time frame: Postoperative day 1 and postoperative day 7
Patient-Reported Recovery After SARME
Time frame: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Clinical Nasal Deviation
Time frame: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Radiographic Nasal Septum Deviation
Time frame: Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
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 30 Sep 2026.
- Individual participant dataSharing planned: No. Individual participant data will not be made publicly available because the study involves sensitive clinical and radiographic data collected at two hospital sites and will be handled in accordance with applicable data-protection requirements and the approved study protocol. Study results will be reported in aggregated or appropriately anonymized form in scientific publications and presentations.
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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.
Thomas Starch-Jensen, Professor study director
Aalborg University Hospital
Hanna Hejlesen, PhD, Head of department study chair
Aalborg University Hospital
Martin Bengtsson, Associate Professor study chair
Skane University Hospital
2 sites in 2 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Tooth-Borne Maxillary Expansion Appliance and Hybrid Tooth-Bone-Borne Maxillary Expansion Appliance in people with Maxillary Transverse Deficiency, run by Aalborg University Hospital at 2 sites in 2 countries.
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 5 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: opening soon, as of the sponsor's last update on 30 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Denmark, Sweden. 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?
Contact Osman Khachab, DDs, MSc (+46 720441061, osmankhachab@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Transverse Skeletal Relapse in External Maxillary Width (time frame: From the end of the distraction phase to 6 months after completion of expansion). 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 30 Sep 2026.