Evaluation The Condylar Displacement Under BSSRO In Different Types Of Split Patterns With Mandibular Setback

Purpose:To study the visualization of three-dimensional reconstruction of the human mandible containing TMJ,we analyzed the effect of the changes of position and distance after sagittal split osteotomy of the condylar process on the articular function in order to study the biological mechanics of temporomandibular joint in the follow-up studies.Methods:The model of mandibular temporomandibular joint was established by using MIMICS software.CT was used to scan mandibular dry bone specimens,the scanned data were imported into the MIMICS software directly in DICOM format.The three-dimensional finite element model was established after the parameters of material properties and boundary constraints were selected.The two-sided mandibular branch sagittal split was simulated using virtual surgical technique.Refers to the clinical data,boundary constraints and the value of masticatory muscle load were setted.Simulation of rigid internal fixation with titanium plate and titanium nails was established.Two methods of bone fracture were designed.Mode 1 was split between the mandibular posterior margin and the bone plate,and Mode 2 was the mandibular hyoid fissure.We simulated the surgical methods for the treatment of mandibular anterior deformity to define and analysis the backward distance of distal segment.Result:1.Comparison of the finite element simulation of distal segments in two different types of split patterns,regardless of the type of split split or receding distance,the position of the external pole of condyle was shifted in the direction of the forward,the inward and the outward poles of the condyle,and the internal pole shifted backwards,outwards,and under.2.In the same mode of split,the changes of the internal and external poles of the condylar process were significant with different receding distance,and statistically significant(p<0.01),and the change of condyle displacement did not increase with the increase of receding distance.3.The sameback distance and different splitting modes have inconsistent effects on the lateral condyle displacement.Conclusion:In this study,the displacement of BSSRO in different receding distance was quantitatively analyzed by finite element method,and the influence of dehiscence on the position of condylar process was observed.The study shows that no matter what type of split or receding amount,ICA was decreased.However,in the way of the posterior margin splitting,the ICA reduced amplitude decreased gradually with the increase of the receding amount,and the decrease amplitude of ICA decreased with the increase of the receding amount in the hyoid fissure.To some extant,the mode of split has an effect on the displacement of the joint.