This in vitro study compared the retentive ability of 11 materials used to cement cast crowns on one implant system. The crowns were cemented to the abutments and the tensile load necessary to remove each casting was measured 30 minutes after cementation in a dry condition at 22 degrees C and after storage for 72 hours in saline solution at 37 degrees C. The results provide a ranking order of the tested materials according to their ability to retain implant restorations. This information, along with studies that better represent the effect of aging, may assist the clinician in selecting a material that is retentive enough to withstand occlusal forces, yet weak enough to allow easy retrieval of cement-retained implant restorations.