The goal of this retrospective observational study is to compare the effects of Clear Aligner Mandibular Advancement (MA) and Twin Block (TB) appliances in treating Class II malocclusion, a condition where the lower jaw is underdeveloped. The main questions it aims to answer are: 1. Does mandibular advancement with clear aligners improve jaw and dental alignment as effectively as Twin Block appliances? 2. What are the differences in soft tissue changes, such as chin advancement and lip position, between these two treatments? Researchers will compare MA and TB appliances to an untreated control group to evaluate their impact on skeletal, dental, and soft tissue outcomes. Participants in the study underwent cephalometric analysis (X-ray measurements) both before and after treatment to assess changes in jaw positioning, overbite, and overjet. The study focuses on how each treatment affects facial aesthetics and dental function. Participants in the study will: * Undergo treatment with either clear aligner mandibular advancement or Twin Block appliances. * Attend follow-up appointments to monitor progress and assess treatment outcomes.
Supplementary information for Study Design It was a retrospective study that collected patients' routine treatment X-rays (before and after treatment) to measure some angular and linear parameters from the X-rays.
Study Type
OBSERVATIONAL
Enrollment
47
The TB group used a single appliance continuously, with appropriate reduction of occlusal surface height by 1 mm when clinically indicated. Both groups had follow-up appointments every 6 weeks.
The MA group underwent stepwise mandibular forward movement with clear aligners (Invisalign, Align Inc, CA, USA) worn for 22 hours/day and replaced every 7 days.
West China School of Stomatology, Sichuan University
Chengdu, Sichuan, China
Changes in Skeletal Measurements ( SNB angle)
This study assesses skeletal changes in patients treated for Class II malocclusion with Twin Block (TB) or Mandibular Advancement (MA) appliances at West China School of Stomatology, Sichuan University. The evaluation focuses on the measurement of the SNB angle, a critical skeletal parameter, using cephalometric radiographs. These radiographs are taken as a routine part of the treatment to capture skeletal positioning before the treatment starts and after the treatment concludes. This allows for an analysis of the angular changes due to the orthodontic intervention, providing insights into the effectiveness of the appliances in correcting malocclusions.
Time frame: Baseline and post-treatment cephalometric radiographs will be taken 1-2 weeks pre and 1-2 weeks post the 12-month treatment at West China School of Stomatology, Sichuan University.
Changes in Soft Tissue Measurements ( soft tissue chin thickness)
This study assesses skeletal changes in patients treated for Class II malocclusion with Twin Block (TB) or Mandibular Advancement (MA) appliances at West China School of Stomatology, Sichuan University. The evaluation focuses on the measurement of the soft tissue chin thickness, using cephalometric radiographs. These radiographs are taken as a routine part of the treatment to capture skeletal positioning before the treatment starts (baseline) and after the treatment concludes (1-2 weeks post the 12-month treatment). This allows for an analysis of the angular changes due to the orthodontic intervention, providing insights into the effectiveness of the appliances in correcting malocclusions.
Time frame: Baseline and post-treatment cephalometric radiographs will be taken 1-2 weeks pre and 1-2 weeks post the 12-month treatment at West China School of Stomatology, Sichuan University.
Changes in Skeletal Measurements (ANB angle)
This study assesses skeletal changes in patients treated for Class II malocclusion with Twin Block (TB) or Mandibular Advancement (MA) appliances at West China School of Stomatology, Sichuan University. The evaluation focuses on the measurement of the ANB angle, a critical skeletal parameter, using cephalometric radiographs. These radiographs are taken as a routine part of the treatment to capture skeletal positioning before the treatment starts and after the treatment concludes. This allows for an analysis of the angular changes due to the orthodontic intervention, providing insights into the effectiveness of the appliances in correcting malocclusions.
Time frame: Baseline and post-treatment cephalometric radiographs will be taken 1-2 weeks pre and 1-2 weeks post the 12-month treatment at West China School of Stomatology, Sichuan University.
Changes in Skeletal Measurements ( mandibular length)
This study assesses skeletal changes in patients treated for Class II malocclusion with Twin Block (TB) or Mandibular Advancement (MA) appliances at West China School of Stomatology, Sichuan University. The evaluation focuses on the measurement of the mandibular length (mm), a critical skeletal parameter, using cephalometric radiographs. These radiographs are taken as a routine part of the treatment to capture skeletal positioning before the treatment starts and after the treatment concludes. This allows for an analysis of the angular changes due to the orthodontic intervention, providing insights into the effectiveness of the appliances in correcting malocclusions.
Time frame: Baseline and post-treatment cephalometric radiographs will be taken 1-2 weeks pre and 1-2 weeks post the 12-month treatment at West China School of Stomatology, Sichuan University
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