A Comparative Study On Printing Medical Model By Fused Deposition Modeling With Various Materials

Objective: The clinical application of 3D printing technology lacks of a relative research and scheme on different materials,different parameters and different application conditions.By optimizing and comparing the printing parameters and differences of 6 kinds of fused deposition modeling materials in preoperative planning,it provides an appropriate guidance scheme to rapidly print preoperative models with different clinical requirements.Methods: A reconstructed trimalleolar fracture model based on CT image data was taken as an example,which was imported into a 3D printer printing with multiple materials [acrylonitrile butadiene styrene(ABS),polylactic acid(PLA)and thermoplastic polyurethane(TPU),polyvinyl alcohol(PVA),polyethylene terephthalate glycol(PETG),and polycarbonate(PC)]according to the four-factor three-level orthogonal array with layer height,printing speed,infill density and scale to print models,respectively.The printing time,model weight,surface roughness,model height,post-processing time and disinfection were recorded as the main indicators.Twenty patients with tri-ankle fractures from October2017 to June 2019 were selected for clinical verification.The patients were randomly divided into group A and B,with 10 in each group.Group A was the conventional treatment group and group B was the 3D assisting treatment group.The operation time,intraoperative blood loss,and the number of fluoroscopies were recorded in the two groups.Orthopedists and patients were invited to participate in a questionnaire about models.Results: 1.The layer height and scale,the infill density and scale,the layer height are the main influencing factors of printing time,model weight and surface roughness for all materials respectively.2.Models printed with ABS took the least printing time,weight,cost,and removing support structure time,acquire the highest accuracy,and be out of shape after sterilization.Models with PLA maintained shape after sterilization.Models with TPU took the most weight and removing support structure time.They maintained shape after sterilization and themselves flexible touch was suitable for printing soft tissue and simulating fracture reduction.Models with PVA took the most printing time and cost.They were badly deformed or disappeared after sterilization,so it was used for printing sacrifice structure.Models with PETG acquired the worst accuracy and deform after sterilization.Models with PC took the more printing time,weight,cost,and removing support structure time,acquired the lower accuracy,and were out of shape after sterilization.3.The questionnaire showed that patients chose PLA print models more,and orthopedist chose TPU print models.Patients preferred to print 1: 1 fracture models,but orthopedists were more willing to choose a model reduced to 80%.Difference doctors and patients believe that the model can objectively reflect the fracture situation.4.The 3D printing auxiliary group was superior to the conventional surgery group in terms of operation time,intraoperative blood loss,and the number of fluoroscopies.Conclusion: The optimization printing parameters of various materials based on orthogonal experiment design provides guidance for printing clinical model.Different materials,scales,layer heights,and infill densities can be used to rapidly print fracture models according to different clinical purposes and needs,which improve doctors and patients' understanding of fractures and surgical plans.It will be an effective method for fractures treatment.