Three-dimensional Finite Element Analysis Of The Number Of Implants With Different Inclinations In The Fixed Restoration Of The Maxillary Edentulous Jaw

Background Clinical and laboratory studies on implantation design of edentulous patients have been widely carried out at home and abroad.Scholars at home and abroad have different opinions on the implantation design scheme.Through three-dimensional finite element analysis and retrospective study of clinical cases,they found the bone area between the anterior wall of maxillary sinus in maxilla or between mental foramen in mandibular jaw can be used for surgery,several parallel or tilted implants can be implanted in the area to support the restoration when the condition of jaw bone is not good.Compared with complete denture and implant-retained overdenture,implant supported fixed denture prosthodontics was favored by patients due to their high chewing efficiency and fixed,but it was the focus and difficulty in the study of oral implantology.It was found that increasing the number of implants and dispersing implants during the design of implant supported fixed denture prosthodontics can reduce the stress around implants and obtain a good stress distribution.Stress around the neck of terminal implant can be reduced when designed the inclined terminal implants and reduced the length of the cantilever beam.Excessive stress is one of the causes of various complications such as screw loosening,bone lossing and implant shedding after implant restoration.However,there are few studies on the number of inclined implants in edentulous implant supported fixed denture restoration,so the increase of the number of inclined implants on the stress distribution of the whole structure of edentulous implant prosthesis still needs to be studied.Objective To study the law of stress distribution on implant surface and bone tissue surface around implant of edentulous implant supported fixed denture,to study the influence of the stress distribution on implant and bone tissue by increasing the number of inclined implant in jaw and to study the influence of the stress distribution of inclined implant in anterior bone area.Method Four different models designed by finite element method with different number of inclined implants which named No.1-6 from right to left in edentulous maxilla,the implant placement sites were fixed,located at the position of 16,14,12,22,24,26 teeth respectively.Model I: No.1-6 implant axial tilted 0 degree;Model II: No.1 and No.6implant were distal tilted 45 degrees,the rest of the implants axial tilted 0 degrees;Model III: No.1 and No.6 were distal tilted 45 degrees,No.2 and No.5 were distal tilted 30 degrees,and the rest of the implants axial tilted 0 degrees;Model IV: No.1and No.6 were distal tilted 45 degrees,No.2 and No.5 were distal tilted 30 degrees,No.3 and No.4 were distal tilted 17 degrees.Using SPSS data processing and principal component analysis(PCA)to analyze the combined stress score and the stress distribution of the four models.ResultThe Mises stress distribution on the surface of implant and bone tissue has definite distribution law,the combined stress on the surface of implant and the bone tissue were the smallest in Model IV.Conclusion Increasing the number of inclined implants can have a positive effect on the biomechanical effect of the fixed denture on edentulous maxilla,the distal tilted implant in premaxillary region can reduce the stress on the implants and bone tissue.