The effect of mandibular advancement with clear aligners compared with activator therapy on maxillary and mandibular volumes: a randomized controlled trial using CBCT

The aim of this study was to evaluate the effects of the Mandibular Advancement Appliance (MAA) system on mandibular and maxillary volumes in growing individuals using three-dimensional cone-beam computed tomography (CBCT), and to compare the results with those obtained using a conventional functional appliance (Activator) and a control group. This single-center, randomized, controlled study included 55 individuals with skeletal Class II malocclusion at cervical vertebral maturation stages 2 or 3. The MAA and Activator groups each comprised 20 participants, while the control group included 15 participants. Volumetric analyses were performed using CBCT data and Mimics 15.0® software. Statistical analyses were conducted using SPSS version 21. An increase in mandibular and maxillary volumes was observed in both the MAA and Activator groups during the treatment period. However, these increases were not statistically significant (p > 0.05). No significant differences were found between the treatment groups and the control group. Within the scope of this short-term treatment protocol, the MAA and Activator systems demonstrated similar effects on maxillary and mandibular volumes. Considering the esthetic and comfort-related advantages of the MAA, this system may be an effective alternative for the treatment of Class II malocclusion. ClinicalTrials.gov NCT07056829 (registered June 29, 2025; retrospectively registered).