A Three-dimensional Finite Element Analysis On Inclination Angles Of The Distal Implants In Edentulous Maxillary With All-on-4 Implant

Objective: To study the effect of inclination angles of the distal implants in the All-on-4 implant denture on the stress value of implant and bone around the implants by three-dimensional finite element method(FEM),and analyze the effect of inclination angles of the distal implants on the All-on-4 implant denture Material and Methods: Ten patiens with edentulous maxillary were selected,and were scanned with CBCT.The CT data were saved with Dicom format.The Mimics,Geomagic and Soliderwork were used to reconstruct the three dimensional model of the edentulous maxillary with All-on-4 imlpants and fixed denture.The three-dimensional finite element models of edentulous maxillary All-On-4implant-supported fixed dentures were meshed in Ansys Workbench 16.0.According to the inclination angle of distal implant,4 groups were set: 0°,15°,30°,45°.The control group were set with single implant denture of the up first molar and were divided into 4 groups too.200 N force were used to simulate the bite force of the old peole and the stress value were measured and analyzed by FEM in the Ansys Workbentch 16.0.The result were analyzed in the Spss 14.0.Result:1.In the study,the three-dimensional finite element models of edentulous maxillary All-On-4 implant-supported fixed dentures were reconstructed and could be used in the FEM to analyze the stress.2.With the increasing of the inclination of the distal implant,the stress on the bone around the implant increased.There were significant difference between the 0 °group with 45 °,30°groop.3.With the increasing of the inclination of the distal implant,the stress on the bone around the mesial implant of the mesial implant discreased.There were significant difference between the 0°group with 15°,30°,45° groups.4.Compared with the control group,the stress of the distal implant in the edentulous maxillary All-On-4 were stronger in the four groups,but there were no singnificant difference between the experiment group and the control group.Conclusion:1.The inclination of distal implant play important role in the edentulous maxillary All-On-4 implant-supported fixed dentures,when the angle changed more than30°,there were significant change in the stress on the bone around the implant.In the clinic,we should put the inclination of distal implant in consideration and reduce the bite force with the inclination increasing.2.The implant denture of first molar in the edentulous maxillary All-On-4implant-supported fixed dentures bared more bite force than the single crown,and inclinic we had better reduce the diameter of the crown to increasing the success rate.