FM Technique in Orthodontic Clear Aligner Therapy: A Single-Arm Clinical Study

Inclusion Criteria: * Age 12 to 45 years (inclusive), either sex, with good oral hygiene and good compliance * Non-extraction orthodontic cases in which the treatment plan requires molar distalization to create space * Periodontally healthy: probing depth (PD) of 3 mm or less at all sites, and no active periodontal inflammation (no sites with bleeding on probing) * No history of orthodontic treatment * Participant and legal guardian voluntarily agree to take part and sign the informed consent form Exclusion Criteria: * Requires combined orthodontic and orthognathic surgery treatment * Missing teeth other than third molars in the maxillary or mandibular arch (first and second premolars must be present) * Diagnosed with severe dental crowding and assessed as requiring an extraction-based treatment plan * Active periodontal disease, uncontrolled periodontitis, or need for systematic periodontal treatment * Systemic disease affecting bone metabolism (for example, uncontrolled diabetes mellitus, osteoporosis, or rheumatoid arthritis) * Long-term use of medications that may affect tooth movement or bone metabolism (for example, bisphosphonates or glucocorticoids) * Pregnancy, breastfeeding, or planned pregnancy during the study period * Obvious symptoms of temporomandibular disorder (pain, clicking, or limited mouth opening) * Known allergy to clear aligner material (for example, polyethylene terephthalate glycol-modified, PETG) * Expected to move away from the local area during the study period and unable to complete the required follow-up visits