Evaluation of stress distribution in implant and surrounding tissues of prosthetic structures by means of finite element stres analysis methots of overdenture prostheses with various retaining attachments supported by titanium and implants in the case of lower jaw complete toothlessness

In overdenture prosthesis with implant retaining, aesthetics, chewing efficacy, prosthesis stability and retention seem to be more satisfactory than conventional complete dentures and therefore patient satisfaction is increased. There are several attachment systems used in implantretained overdentures and attachment selection is an important factor affecting prosthetic retention. In our study, overdenture prosthesis with locator holder, overdenture prosthesis with novaloc holder, overdenture prosthesis with ball holder and overdenture prosthesis with bar holder were performed on 2 vertical and angled implants in the lower toothless jaw. 100 N vertical and 100 N oblique forces from the center of the first mandibular molar teeth were applied on each model. In the models created in computer environment, the values formed as a result of the forces applied from different directions were compared. Retentive elements used in implant-supported overdenture prostheses vary in shape, size, design and material content. Locator retained, Novaloc retained, Ball retained and Hader bar retained were used in our study. The study was carried out by using three dimensional finite element stress analysis. As a result of the applied vertical and oblique forces in these models; stress values, distribution and concentration areas in the implant and bone were examined. Von Misses stress, maximum principal stress and basma stresleris values and stress distributions in the implant, cortical bone and spongious bone in each of the scenarios were examined. The principal stress values were higher in oblique loading than in vertical loading conditions. The ultimate attention should be paid in order to orient the chewing forces along the long axis of the implant. For the routine use of this material as a dental implant material; animal and long-term clinical studies are needed. Keywords: Elastic modulus, finite element stress analysis method, abutment, titanium, Cfr-Peek