Analysis of load transfer and stress distribution by an implant-supported fixed partial denture

This study simultaneously examined the load transfer and stress distribution by an implant-supported fixed partial denture. A mandibular implant framework with implants connected to the abutments was embedded in a three-dimensional photoelastic model of a mandible. Strain gauges were attached on the superior surface of the framework, and a vertical load of 7.5 kg was applied to seven points on the framework. The measurements derived from this simulation revealed that (1) there was a direct proportion between the stress distribution in the metal framework and stresses created in the supporting structure around the implants; (2) the mode of load transfer and stress distribution was directly proportional to the distance of the components from the loading point; and (3) when the cantilever was loaded, the major part of the stress was distributed within the cantilever in the connection to the distal abutment. In this simulation, stress was distributed over the two, or maximum three, closest implants with the distal implant the most stressed.