Reflection photoelastic stress analysis of a dental bridge.

In stress analysis applications emphasis is placed on careful determination of the stresses for the improvement of design. In nondestructive testing importance is placed on reliability and quality, and as a result of this, observation of surface strains is of interest. Earlier photoelastic studies by El-Ebrashi et al 1-7 concerned, for the most part, two dimensional photoelasticity. In two dimensional studies a plastic model must be built, whereas the photoelastic coating method has the advantage of using the structure itself. The technique of photoelastic coatings is basically a method that provides a visual display for the observation and measurement of stress distribution on the surface of parts under load.8 In this study a four unit posterior gold bridge was coated and the magnitudes of the strains were recorded at several locations as a function of load and position of loading.