Three- Dimension Finite Element Stress Analysis Of Influence Of The Configuration And The Bone Quantity Of The Maxillary Sinus Floor To Implant Supported Fixed Bridge

The implant supported prostheses have predominance that traditional ones can not compete with. They have been successfully used to treat edentulous patients. With the maturation of osseointegration theories and the improvement of implant materials, the success rate of implant rehabilitation has been improved, but implant failures were reported occasionally. The one of main causes of implant failure is stress centralizing in bone, and the movement on the surface of implant and bone, which induce the absorption of bone around implant. So, the success of dental implants needs the implants with better bio-mechanic compatibility with the exception of better biocompatibility. Nowadays, little wound in implant supported prostheses is one of aspects of development of implant technology. At the local area of the maxillary sinus floor, the implant can be installed in a tilted direction as an alternative to sinus grafting to reduce the pain of patients when the bone quantity of the maxillary sinus floor is comparatively insufficient. During the design of implants, the angle of the tilted implant, the implant diameter and length are important aspects should be regarded. When different designs of implants are used, with the loads on denture, whether the stress distribution on surface is reasonable or not will influence the formation and maintenance of osseointegration surface directly, then influence the success rate and long-term effect of implant-supported prostheses. At the present time, the technology of implant is more and more grown up, but implant treatment in the atrophic maxillary represents a challenge. In this experiment, we used the MSC/Abaqus software, from bio-mechanic point, to study one aspect of implant shape—design of implant thread. With software we made up four different groups of models according to angle of the tilted implant, diameter, length and whether or not to use a comparatively short implant in maxillary sinus floor. Vertical concentrative and deconcentrative forces of 100N were applied to the model, then we investigated stress distribution of implant with different designed under static load, tofind out the characteristic of stress distribution, the Von-Mises maximum stress values to compare all the different designed models, to reveal the bio-mechanic influence of different designs of implant on surface of implant and bone, and to help clinical doctors choose implant systems and to help factories make implant better. In this research, the result was demonstrated by histogram and graphs: the histogram can reflect the Von-Mises stress peak values of surface of the two implants and bone under all kinds of conditions, and the charts was used to indicate the characteristic of stress distribution of one implant under different conditions. According to the stress nephogram of every group of model, we looked into the stress peak value of the cervix of 7 implant and the root of 5 implant, at the same time, we noted data of four points of implant (the first point is the cervix of implant, central section is the second one, the root of implant is the fourth one, the third point is the midpoint of the second one and the fourth one), and drew the graphs of stress values, to compare the characteristic of stress of different models. According to the data and graphs, we drew such conclusions as followed: 1,The angle of tilted implant is smaller while the stressdistribution is equality, and the stress concentration is not notability. It is noticeable that the region of flimsy cliff in buccally bone in the field of former molar should be avoided. 2,The requirement for the length of the implant is that the longer the better. Clinical doctors could choose implants according to the requirement. 3,The diameter of implant is bigger that will make the stress distribute equably on the surface of implant and bone is equality, but the diameter should be matching up the maxillary diameter length, and should not be too big. 4,Because the maxillary sinus floor 's complexity and its unpredictability , it will prevent from the bone cliff of local is so thin that the stress centralize in the field . 5,Implanting comparatively short implant in bone maxillary sinus floor will make stress distribution on the surface of implant and bone is equality, but the doctor need not choose the longer implant. 6,The stress distribution much centralize in the field of the cervix and root of implant. The peak value of concentrative...