The importance of Marginal adaptation of fixed Prosthodontics is to assess the smallest number of gap meas-urements on margins of single crowns to get relevant results for gap analysis. The most critical factors affecting Marginal adaptation of fixed Prosthodontics includes the material used, the type of finish line and other factors that include the finish line and the durability of the copings like the function of the firing procedures. The results of this study concluded that a perfect marginal is one of the most important technical factors for the long-term success of any restoration. As a sizeable marginal opening concedes more plaque accumulation, gingival sulcular fluid flow, and bone loss, following in microleakage, recurrent caries, periodontal disease and a decrease in the longevity of the prosthetics restorations. This problem might complicate by fixed partial restorations with vital abutments.
Key words: Marginal adaptation, prosthodontics, crowns