Three-Dimensional Evaluation of Pharyngeal Airway and Facial Dimension Changes in Skeletal Class II Patients Treated With Twin Block Versus Myobrace Appliances
- Conditions
- Class II Division 1 Adolescent Patients
- Registration Number
- NCT06976749
- Lead Sponsor
- University of Baghdad
- Brief Summary
This study is intended primarily to compare the effects of two Class II correction appliances, namely Twin block and Myobrace appliances, on pharyngeal airway dimensions during the treatment of class II division 1 adolescent patients, also evaluates three dimensional (3D) changes of pharyngeal airway including: minimum cross-sectional area and volume using Cone Beam Computed Tomography (CBCT), skeletal, dentoalveolar, and soft tissue changes using cephalometric analysis, and three dimensional (3D) soft tissue changes using facial scans. The hypothesis being a consideration of no significant difference in the changes of pharyngeal airway and facial dimensions in skeletal class II patients before and after treatment with Twin block and Myobrace.
- Detailed Description
This study is a multicenter randomized comparative clinical trial, employing non-stratified randomization in two-parallel arms with equal allocation ratio of 1:1. Patients will be recruited from Orthodontic Clinic at the College of Dentistry, University of Kufa, and from specialized dental centers affiliated to the Iraqi Ministry of Health, in addition to some private clinics. Initially, the patients will be assessed for eligibility to participate in the study according to the inclusion criteria. Then, the parents will be informed verbally about the purpose of the study and will be provided with the informed consent form to be signed. Patients will be treated using two types of functional appliances ( Twin Block and Myobrace) for six months. Regular follow-ups will be conducted during the course of the treatment and progress will be charted out at 4-weeks intervals.
Participants will be randomly assigned to one of two groups, each receiving one of the specified treatments over a six-month period.
Group I: Twin Block Appliance
* Design: Comprises maxillary and mandibular components anchored using Adams' clasps on the first permanent molars and lower first premolars. A passive labial bow will be incorporated into the upper arch, with ball-end clasps for additional retention.
* Bite Registration: Achieved through a symmetric protrusive bite using modeling wax, ensuring an edge-to-edge incisal relationship with a 2-3 mm bite opening between central incisors.
* Inclined Bite Blocks: Positioned at a 70° angle to facilitate forward mandibular displacement.
* Patient Instructions: Continuous wear is mandated (24 hours/day), excluding periods of oral hygiene. Adjustments using self-cured acrylic may be made for further mandibular advancement.
Group II: Myobrace Appliance
* Selection: Appropriate sizing determined by measuring the inter-canine distance using a specialized ruler.
* Fitting: Ensures alignment of upper canines within designated slots, matching the appliance's midline with the dental midline.
* Wear Protocol:
* Week 1: Gradual increase in daytime wear duration.
* Week 2 Onwards: Overnight wear targeting at least 8 hours.
* Post Week 4: Combination of 1-2 hours daytime wear plus overnight usage.
* Supplementary Activities: Incorporates exercises targeting breathing habits, tongue positioning, swallowing patterns, and lip function.
Imaging Protocols:
* Cone Beam Computed Tomography (CBCT):
* Timing: Conducted pre-treatment and at end of study .
* Positioning: Subjects seated upright with the Frankfort horizontal plane parallel to the floor, maintaining natural occlusion, relaxed lips, and resting tongue posture.
* Parameters: Scans performed using the Morita Veraview X 800 device (100 kV tube voltage, 3 mA tube current, 14 x 15 cm field of view, 0.08 mm voxel size, 18-second scan time).
three dimensional (3D) Facial Scanning:
* Equipment: Utilizes an iPhone Pro 14 equipped with the 3D Scanner App™.
* Landmark Identification: Seventeen specific facial landmarks will be marked using black eyeliner to ensure consistency.
* Participant Positioning: Subjects will be seated in a relaxed posture with a natural head position under standardized lighting conditions.
* Pre-Scan Preparations: Removal of glasses, jewelry, and use of hairbands to minimize obstructions.
* Data Processing: Captured three dimensional (3D)facial models will be exported as Standard Tessellation Language (STL) files and analyzed using Blender 3.6 LTS software for linear and angular measurements.
Data Analysis:
* three dimensional (3D) Model Reconstruction: CBCT data will be processed using ProPlan CMF 3.0 (Materialise) software.
* Segmentation: Hard tissues and upper airway structures will be delineated based on specific Hounsfield Unit (HU) thresholds.
* Pharyngeal Airway Segmentation: Divided into nasopharynx, velopharynx, glossopharynx, and hypopharynx, with precise anatomical boundaries defined for each segment.
Measurements:
* Airway Analysis: Assessment of minimum cross-sectional area, total airway volume, and pharyngeal airway length.
* Soft Tissue Evaluation: Linear and angular anthropometric measurements derived from 3D facial scans.
Recruitment & Eligibility
- Status
- ENROLLING_BY_INVITATION
- Sex
- All
- Target Recruitment
- 50
- Age: 10-14 years, at growth spurt phase as determined by the cervical vertebrae maturation stage (C3- C4 ) assessed by lateral cephalograms.
- Skeletal relationship: skeletal class II (ANB angle > 4°) with normal maxilla (SNA angle 78°- 84°), and retrognathic mandible (SNB angle < 77 °).
- Dental relationship: Moderate to severe dental class II division 1 malocclusion with overjet 6 -10 mm.
- Convex facial profile.
- Well aligned/mild crowding (< 4 mm) of dental arches.
- Good to fair oral hygiene status as based on a simplified oral hygiene index (OHI-S).
- Normal or decreased lower facial height (SN-MP angle ≤ 32).
- Previous orthodontic/orthopedic treatment.
- Patients with dental open bite
- Patients with obvious facial asymmetry.
- Patients with orofacial cleft.
- Previous extractions.
- Presence of mandibular shifts.
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Primary Outcome Measures
Name Time Method minimum cross-sectional area of the pharyngeal airway in (mm^2) using Cone Beam Computed Tomography (CBCT) From enrollment to the end of treatment at 6 months 3D measurements of pharyngeal airway minimum cross-sectional (mm\^2) will be performed for all participants of both groups at two stages before treatment and at the end of the study using CBCT
- Secondary Outcome Measures
Name Time Method three dimensional changes in the volume of the pharyngeal airway using CBCT From enrollment to the end of treatment at 6 months 1. pharyngeal airway volume in (mm\^3) using CBCT.
Skeletal changes using cephalometric analysis From enrollment to the end of treatment at 6 months * SNA angle (relative anteroposterior position of maxilla to anterior cranial base).
* SNB angle (relative anteroposterior position of mandible to anterior cranial base).
* ANB angle (relative anteroposterior position of maxilla to mandible).
* SN-Pog angle (relative anteroposterior position of chin to anterior cranial base).
* PP-MP (Angle between palatal and mandibular plane).
* SN-MP (Angle between SN and mandibular plane).
* Ar-Go-Me ((Gonial Angle, it refers to the relation between the body of the mandible and the ramus).Soft tissue changes using cephalometric analysis From enrollment to the end of treatment at 6 months * NL angle (nasolabial angle).
* U Lip-E line (upper lip to Rickett's Esthetic line).
* L Lip-E Line (lower lip to Rickett's Esthetic line).Dentoalveolar changes using cephalometric analysis From enrollment to the end of treatment at 6 months * U1-PP (upper incisor inclination to the palatal plane).
* L1-MP (lower incisor inclination to the mandibular plane).Dental changes using study models From enrollment to the end of treatment at 6 months overjet, overbite, inter canine, inter premolar, and inter molar widths in (mm)
three dimentional soft tissue changes using facial scans From enrollment to the end of treatment at 6 months Total face height (mm) Upper anterior face height (mm) Lower anterior face height (mm) Bigonial width (mm) Mandibular length (mm) Soft tissue convexity angle Total face convexity angle Gonial angle Alar base width (mm) Lip width (mm) Nasolabial angle Labiomental angle
Trial Locations
- Locations (1)
University of Baghdad, College of Dentistry
🇮🇶Baghdad, Iraq