The purpose of this study was to analyse the magnitude and distribution of stress using a photoelastic model form and distal extension removable partial dentures. A photoelastic models were made of the epoxy resin (PL-8) and hardner(PLH-8) with the acrylic resin teeth used and was coated with Lacquer spray(silver color)at lingual surface of the epoxy resin models with five designed prostheses.
A unilateral´ vertical load of 12kg to the central groove of 1st molar, with using of special designed jig, fixture, loading` device and the reflective circular polariscope.
When the unilateral vertical load applied, the following results were obtained
1. Distal extension fixed partial denture mainly produced stress distribution on around abutment teeth, clasp retained unilateral partial denture mainly produced stress distribution on residual ridge, attachment retained partial denture produced even stress distribution.
2. The magnitude and distribution of the stress concentration on around abutment teeth was higher in order of distal extension fixed partial denture, clasp retained partial denture, attachment retained partial denture,
3. The magnitude and distribution of the stress concentration of the residual ridge area was higher in order of attachment retained partial denture, clasp retained partial denture, distal extension fixed partial denture.
4. In bilateral partial denture, the magnitude and distribution of the stress concentration was more distribute than unilateral partial denture.
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