Retrospective Evaluation of Invisalign® Mandibular Advancement in Growing Patients: Cephalometric, PAR and 3D Molar Displacement Outcomes

<b>Background</b>: Class II malocclusion is one of the most prevalent dentoskeletal disorders, usually caused by mandibular retrusion. The Invisalign^® Mandibular Advancement System is an aesthetic, comfortable alternative to conventional braces for growing patients allowing mandibular projection and dental alignment. This retrospective study assessed the effectiveness of the Invisalign^® Mandibular Advancement (MA) System in growing patients with mandibular retrognathia. <b>Methods</b>: At treatment onset, seventeen patients were divided into the following two groups according to the aligner system used and cervical vertebral maturation stage: the Invisalign^® First group (CVM2), and the Invisalign^® Teen group (CVM3, some transitioning to CVM4), all treated with the Comprehensive Package. Treatment efficacy was evaluated through cephalometric analysis, occlusal classification, and three-dimensional tooth movement assessment. Cephalometric evaluations were performed pre-(T0) and post-treatment (TF). In addition, a clinical follow-up during the retention period was conducted to assess post-treatment stability. <b>Results</b>: Significant dentoalveolar and skeletal changes were observed in both groups. The Teen group showed greater mesial movement of the lower molars (3.57 ± 1.26 mm) compared to the First group (1.34 ± 0.48 mm; <i>p</i> < 0.001). Conversely, the First group showed greater distal movement of the upper molars (2.24 ± 0.64 mm) compared to the Teen group (1.35 ± 0.69 mm; <i>p</i> = 0.002). The PAR index showed significant reductions in both groups (<i>p</i> < 0.001), and although the Teen group achieved greater improvements, the First group demonstrated a clinically relevant reduction (23.60 vs. 19.43 points), despite two severe cases that did not achieve full Class II correction. <b>Conclusions</b>: Both the Invisalign^® First and Comprehensive Package for teens systems improved occlusion and skeletal patterns. These findings support the MA System as an effective option for correcting Class II malocclusion during growth.