Photoelastic stress analysis is one of the useful methods for evaluating stress distribution in dentistry.
So, three-dimensional photoelasticity was used in the present study. The purpose of this study was to investigate the hypothesis that the magnitude and distribution of the occlusal stresses, transmitted through the complete denture base to the edentulous ridge, would be influenced by shape of edentulous ridge and occlusal form of artificial teeth of complete denture.
For this study, three epoxy tesin models with normal edentulous ridge were duplicated and complete dentures were constructed with 30˚anatomic teeth on these models.
Six epoxy resin models with extremly resorbed edentulous ridge were duplicated and complete dentures were constructed. Three of them were arranged with 30˚anatomic teeth and the others with 0˚non-anatomic teeth.
The mounted dentures on the Hanau H-2 articulator were loaded in a pure vertical direction with 6㎏ on the center of the articulator in centric relation, lateral and protrusive functional positions.
The stresses were frozen into an epoxy resin model at 130℃ in a stress-freezing furnace.
The stress-frozen epoxy resin models were sliced into 6㎜ thickness.
The slices were examined with a circular polariscope.
The results were as follows:
1. In centric relation, dentures constructed with 30˚anatomic teeth showed higher stresses on the molar area than those with 0˚non-anatomic teeth.
2. In lateral functional position, the working side showed higher stresses than the balancing side.
3. In protrusive position, stress distribution was symmetrical on the posteriors and the stresses were concentrated on the anteriors.
4. Higher stresses appeared on the resorbed edentulous ridge than the normal edentulous ridge.
5. The dentures with 0˚non-anatomic teeth showed lower stress on the molar area than those with 30˚anatomic teeth but previously showed higher stresses on the aneriors.
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