| In recent years, the research about immediate loading of dentalimplant have been attached more and more importance to. Threedimensional finite element analysis is an effective and reliable way to dosome relative stress and DOF studies in the field of oral implantology.In contrast with the delayed loading protocol, immediate loading ofdental implants is defined as a treatment procedure that the implantswere loaded with a provisional restoration at the same day the implantswere placed or shortly thereafter. The use of such protocols has manyobvious advantages for the patients, for example, greatly increasedcomfort, function, speech, and stability and so on.According to current opinions, the primary stability of theimmediately loaded implants is thought to be the most importantdetermining factor on immediate implant loading. The literature suggestthat there are several methods may improve the stability of theimmediately loaded implants, including choosing high quality bone type,placing the implants with the press-fit technique, choosing the screwtype implants and splinting the implants.This study is a part of series studies of the new type implant system, which is aimed at comparing DOF value in the bone-implantsurface under dynamic loads between two new type implant withdifferent lengths and two models with different quality bone bythree-dimensional finite element analysis method, thus provide academicand experimental basis for further designs and improvements of dentalimplants.Methods:â‘ By establishing a three-dimensional finite element modelof a new type dental implant for immediate loading, the interfacial statusof the primary press-fit stress can be simulated by the "Interference FitOptions" in the finite element software, which will provide a basis forfurther study of the biomechanical characteristics of the new type dentalimplants.â‘¡The micromotions of the finite element models with different implantlengths (8mm, 6mm) under dynamic loads were computed with theANSYS software.â‘¢To alter the parameters of mechanical properties of trabecular boneand construct two type models. The micromotions of the finite elementmodels with two type bones(Typeâ… and Typeâ…¢) under dynamic loadswere computed with the ANSYS software.Results:â‘ The accurate finite element model of mandible with the newtype dental implant for immediate loading was established. Thebone-implant interfaces of the models were defined to simulate theinterfacial statues of immediately loaded implants which include theprimary press-fit stress and the frictional contact of bones and implants. â‘¡In the same bone density, increasing the length of implant from 6mmto 8mm can decrease the vertical and horizontal micromotion by amaximum of 28% and 24% respectively.â‘¢In the Typeâ… and Typeâ…¢trabecular bone, the maximum micromotion occurred in the region ofcortical bone adjacent to the implant neck. However, the micromotionvalue in Typeâ… bone is higher than Typeâ…¢bone, and the DOF contourgraphs suggest that the micromotion distributions are different.Conclusions:â‘ The biomechanical similarity, the geometrical analogyand clinical indication of the model were quite good. The interfacialstatus of the primary press-fit stress can be simulated by the"Interference Fit Options" in the finite element software, which willprovide a basis for further study of the biomechanical characteristics ofthe immediate loading the new type dental implants.â‘¡The increase of the length of implant can decrease both the verticaland horizontal interfacial micromotions. The results also suggested thatlonger implant increase the vertical stability more efectively.â‘¢With the decrease of bone density, the maximum micromotion valueincreased. And the zone of implant which occursed micromotionextended.
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