There have been many materials and application methods developed in order to overcome the complications related with implant supported restorations. Prosthetic failures still could emerge in spite of all advanced applications. One of the most common reasons of a prosthetic failure was shown to be the excessive occlusal forces. Excessive occlusal forces may cause prosthetic complications or component fractures as well as with progressive crestal bone loss. The aim of this retrospective study was to evaluate the prosthetic complications of the implant supported fixed prosthesis followed up to four years. A Cox proportional hazard regression analysis was used to evaluate possible associations. Long bridges and single tooth crowns were associated with porcelain fracture (p<0.01, HR: 4.46) and cement loosening (p<0.05 HR: 3.22) respectively. Care must be given to occlusal alignment of the implant supported crowns/bridges to overcome long-term complications. Key Words: Implant prosthesis, prosthetic failures, retrospective analysis.