Comparative Effect of Clear Aligner Mandibular Advancement and Twin Block Appliances in Class II Malocclusion

Comparative Effect of Clear Aligner Mandibular Advancement and Twin Block Appliances in Class II Malocclusion

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.

Inclusion Criteria:

• Patients who have completed MA or TB treatment at the West China Hospital of Stomatology Orthodontic Department.
• Pretreatment lateral cephalometric radiographs showing cervical vertebral maturation stage (CVSM) II or III.
• Patients in the mixed dentition or early permanent dentition stages.
• Class II Division 1 malocclusion according to Angle's classification
• ANB angle > 4°; SNB ≤ 78°.
• Comprehensive medical records and necessary data available pre- and post-treatment.

Exclusion Criteria:

• Missing teeth, supernumerary teeth, or severe dental malformations affecting function.
• Poor oral hygiene.
• Systemic diseases or congenital deformities.
• History of dental or maxillofacial trauma.
• Incomplete or missing records.