ANALYSIS OF STRAIN AT SELECTED BONE SITES OF A CANTILEVERED IMPLANT-SUPPORTED PROSTHESIS

Cantilever length of the superstructure of an implant-supported prosth esis can be affected by the location, number, and dimensions of the im plants, arch form, opposing dentition, and functionally generated forc es. In this study, the effects of cantilever length on load distributi on to implants was analyzed. A fresh bovine rib was used to create a c linical simulation in which three implants were used to support an imp lant prosthesis. The implants were connected by means of a cantilevere d superstructure. Six linear strain gauges were placed in strategic lo cations where it has been reported that stress is concentrated. The mo del was loaded with an Instron machine and the load was applied at 0, 5, 10, 15, 20 and 25 mm along the cantilever length. Each loading test was repeated five times, and loads of 10 and 20 pounds were applied. Dynamic registration of the strain was recorded at each gauge. Signifi cant differences in the magnitude of strain between the six strain gau ge locations were recorded with the 10 and 20 Ib loads and at all cant ilevered lengths. The results revealed that the greatest maximum strai n occurred at the strain gauge positioned on cortical bone over the ap ex of the most distal implant under both loading conditions.