Internal setting expansion of a dental casting investment measured with strain gauges

A study was undertaken to investigate the feasibility of using strain gauges to evaluate the internal setting expansion of dental casting investments. A strain gauge was invested in the center of a casting ring to determine the linear setting expansion at the site of the wax pattern. The findings suggest that strain gauges can be used to measure setting expansion internally more accurately than volumetric or external surface measurement techniques. It was also found that winged strain gauges were more stable in the investment than wingless strain gauges.