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

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.

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.

• 待定
• Tooth-Borne Appliance

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.

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.

• 哈
• Hybrid Appliance

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.

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.

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.

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.

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.

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.

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.

Clinical attachment level will be measured in millimetres at standardized periodontal sites around selected maxillary teeth, with corresponding mandibular teeth assessed as controls.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.