Tooth-Borne (TBA) Versus Hybrid Expanders (HA) in Surgically Assisted Rapid Maxillary Expansion (SARME) (SARME-TBA/HA)

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.

Study Overview

• Status: Not yet recruiting
• Conditions: Maxillary Transverse Deficiency
• Intervention / Treatment: Device: Tooth-Borne Maxillary Expansion Appliance; Device: Hybrid Tooth-Bone-Borne Maxillary Expansion Appliance

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 Type: Interventional
• Enrollment (Estimated): 32
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Osman Khachab, DDs, MSc; Phone Number: +46 720441061; Email: osmankhachab@gmail.com

Study Locations

• Denmark
  • Aalborg, Denmark, 9000
    • Department of Oral and Maxillofacial Surgery, Aalborg University Hospital
    • Contact: Thomas Starch-Jensen, Professor; Phone Number: +4523266370; Email: thomas.jensen@rn.dk
    • Contact: Hanna Hejlesen, Head of department; Phone Number: +45 28519770; Email: hanna.hejlesen@rn.dk
    • Principal Investigator: Osman Khachab, DDs, MSc
• Sweden
  • Skåne County
    • Lund, Skåne County, Sweden, 22242
      • Skåne University Hospital
      • Contact: Martin Bengtsson, Associated professor; Phone Number: 004646171169; Email: Martin.N.Bengtsson@skane.se

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• 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.

Exclusion Criteria:

• 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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Tooth-Borne Appliance (TBA); 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.	Device: Tooth-Borne Maxillary Expansion Appliance; 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.; Other Names: TBA; Tooth-Borne Appliance
Experimental: Hybrid Appliance (HA); 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.	Device: Hybrid Tooth-Bone-Borne Maxillary Expansion Appliance; 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.; Other Names: HA; Hybrid Appliance

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	From the end of the distraction phase to 6 months after completion of expansion

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Midpalatal Sutural Expansion Width	Midpalatal sutural expansion width will be measured in millimetres on axial CBCT images at the incisor, canine, first premolar, and first molar levels. Changes between T0, T1, and T2 will be calculated to characterize sutural opening during the distraction phase and subsequent change during the consolidation period.	Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion
Change in Maxillary Midline Diastema Width	The width of the midline diastema between the maxillary central incisors will be measured in millimetres on digital dental models obtained from standardized intraoral scans. Measurements at T0, T1, and T2 will be compared to assess development of the diastema during expansion and subsequent change during consolidation.	Baseline before surgery, end of the distraction phase approximately 15-30 days after surgery, and 6 months after completion of expansion

Collaborators and Investigators

• Sponsor: Aalborg University Hospital
• Collaborators: Lund University Hospital
• Investigators: Study Director: Thomas Starch-Jensen, Professor, Aalborg University Hospital; Study Chair: Hanna Hejlesen, PhD, Head of department, Aalborg University Hospital; Study Chair: Martin Bengtsson, Associate Professor, Skane University Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): January 1, 2027
• Primary Completion (Estimated): December 1, 2031
• Study Completion (Estimated): December 1, 2031

Study Registration Dates

• First Submitted: September 16, 2026
• First Submitted That Met QC Criteria: September 27, 2026
• First Posted (Actual): September 30, 2026

Study Record Updates

• Last Update Posted (Actual): September 30, 2026
• Last Update Submitted That Met QC Criteria: September 27, 2026
• Last Verified: September 1, 2026

More Information

Terms related to this study

• Keywords: Cone-Beam Computed Tomography; CBCT; SARPE; Maxillary Expansion; Skeletal Anchorage; Surgically Assisted Rapid Maxillary Expansion; SARME; Surgically Assisted Rapid Palatal Expansion; Tooth-Borne Appliance; Hybrid Appliance; Skeletal Relapse; Dentoalveolar Expansion
• Other Study ID Numbers: SARME-AAL-2026

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

IPD Plan Description

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.

Drug and device information, study documents

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