Potential for vertical control using direct 3D‑printed mandibular advancement clear aligners.

OBJECTIVES

To evaluate the biomechanical performance of the direct 3D‑printed monoblock mandibular advancement clear aligner (MACA) designs intended for different vertical control objectives via finite element analysis (FEA). MATERIALS AND

METHODS

An FEA model was constructed from CBCT and intraoral scans of a 12-year-old Class II patient. To isolate design-dependent effects, three monoblock MACA designs for different vertical control objectives were tested on this single, morphology‑controlled skeletal model. Passive tension from six craniofacial muscles was simulated during occlusal reconstruction. Appliance deformation, mandibular displacement, and tooth movement were analyzed.

RESULTS

All three MACAs demonstrated satisfactory manufacturability and maintained stable mandibular advancement under muscular tension. Low-angle MACA intruded lower incisors while creating posterior interocclusal space that may be permissive for subsequent vertical adaptation under clinical conditions, aligning with treatment objectives for low‑angle cases. Lower incisor labial inclination was observed, which could be mitigated by localized appliance thickening. Average-angle MACA intruded anterior teeth while maintaining posterior height and mandibular plane angle. High-angle MACA induced molar intrusion. When combined with targeted anterior intrusion, this dual mechanism provided precise vertical control and may be associated with counterclockwise mandibular rotation.

CONCLUSIONS

This study demonstrates the design capability of direct 3D‑printed MACAs and proposes preliminary design principles for customized MACAs addressing different vertical treatment objectives. CLINICAL RELEVANCE: This study provided preliminary design principles for customized MACAs. Pattern-specific MACA designs may inform treatment strategies, but clinical validation through studies incorporating true anatomical variation across different vertical skeletal patterns is essential before clinical application.