Analyzing the strength rage occured on implant-supoorted removable prosthesis by using different number and diameter implants by using 3-dimensional finite element analysis program

Since osseo-ıntegrated implants were introduced for the rehabilitation of the edentulous patient in the late 1960s, a tremendeus awareness and subsequent demand have arisen in the field. In recent years as a result of advances in oral implantology, the treatment of partially edentulous arches with implant supported fixed prosthesis has been widely accepted as an alternative to conventional removable prosthesis. However , some clinical studies have reported variable rates of failure. Implant failure is reported to be caused by poor oral hygiene, poor bone quality , medical status of the patient and biomedical factors. The biomedical factors have been stressed by various authors. Micromovement of the implant fixture and excessive stres at the implant-bone interface has been suggested as potential cause for peri-implant bone loss and failure. The biologic response of bone to mechanical loads and selection of implant positions affect implant longevity. Since load is transferred to bone through implant, careful planning and execution of the fixture insertion are the important factors in achieving appropriate stres distribution in the bone. Thus, the transfer of functional loads and accompanying stress distribution in a bone-implant-prosthesis assembly depend on the physical properties and spatial geometric configuration model of each component. Various studies indicate a higher rate of implant lose in the maxilla in comparison with the mandible. It has been suggested that the amount and quality of maxillary bone is responsible for the higher rate of implant failure in this area. In case of edentulous maxilla, the rehabilitation can be obtained by using implant-supported removable prothesis or implant-supported fixed prosthesis. Factors such as cost, cosmetic and amount of mechanical load must be considered before the treatment planning. The aim of this study is to analyze the strength range occured on implant-supported removable prothesis by using different number and diameter implants, by using 3-dimensional finite element analysis program. For this purpose, 3D models of an athrophic maxillary model was modeled by using an Engineering Software Marc 2005 (MSC Software). Also implant designs, ball attachments and different loading conditions were applied with the same program in order to simulate lifelike conditions. In this study, 6 groups including different number and diameter of implants were formed and stres values were compared. Four-implant models showed less stres values in comparison to 2-implant models. Keywords : Dental implant, edentulous maxilla, finite element stres analysis, implant-supported removable prosthesis