Treatment of mandibular fractures remains a pressing issue in maxillofacial surgery. This paper presents a novel single-jaw splinting technique (RF patent No. 2735258) for the immobilization of bone fragments in fractures located within the dental arch. Mathematical modeling using the finite element method (FEM), based on computed tomography data from one volunteer, was performed to assess its biomechanical efficiency. A 3D model of the mandible with the fixation construct and an indenter (simulating occlusal load up to 50 N) was constructed. The modeling results showed that the relative movement between the fragments was approximately 25 µm, which is comparable with literature data for two-titanium-plate osteosynthesis. The maximum equivalent stress values in the metal splint reached 100 MPa, and in the splint these reached 3 MPa. The developed method ensures stable fixation without involvement of the maxilla. The analysis involved only a single model and no experimental validation; therefore, confirmation in further research is required. Nevertheless, the obtained data suggest that the method is promising as an alternative to existing immobilization techniques.