A Novel 3D-Printed Titanium Prosthesis with Osseointegrated Dental Implants for Reconstruction of Segmental...

Segmental mandibular defects present complex reconstructive challenges and are associated with significant functional and aesthetic morbidity. While vascularized bone flaps remain the standard for reconstruction, they are associated with donor-site morbidity, prolonged operative times, and limitations in predictable dental rehabilitation. This proof-of-concept study evaluated the mechanical feasibility, in a synthetic bench-top model, of a patient-specific, 3D-printed titanium mandibular prosthesis incorporating conventional dental implants for both dental rehabilitation and biological anchorage via osseointegration.

The prosthesis was digitally designed and fabricated in Ti6Al4V-ELI titanium alloy by powder-bed fusion additive manufacturing. A 25 mm critical-sized segmental defect was created in synthetic polyurethane mandible models, and prototype constructs were assembled with osteosynthesis screws and conventional dental implants engaging the residual mandible. Static load-to-failure testing was performed on a single prototype construct. Dynamic cyclic loading at 40-60 N and 2 Hz for 500,000 cycles was performed on three prototype constructs and a control reconstructed with a conventional 2.5 mm reconstruction plate under an identical protocol.

The prosthesis demonstrated accurate fit and reproducible assembly. Static testing resulted in failure at 213.9 N, occurring within the mandible model rather than in the prosthesis, fixation screws, or implant-prosthesis interface. All prototype constructs and the control completed 500,000 cycles without catastrophic failure, visible deformation, or loosening of fixation screws. The change in per-cycle displacement range over testing was small in all constructs and showed no progressive increase, indicating an absence of appreciable plastic deformation. Reverse torque testing demonstrated no implant loosening.

This proof-of-concept study supports the mechanical feasibility of a novel 3D-printed titanium mandibular prosthesis under defined loading conditions in a synthetic bench-top model. Osseointegrated dental implants are intended to provide biological anchorage in addition to mechanical fixation, although osseointegration was not assessed in this model. This design concept warrants further translational investigation.