Stress Distribution by Improved Designs of Obturator Frameworks Using Photo-elastic Resin Models. In Vitro Study

Abstract

Obturator is a prosthetic appliance that is used to restore irreparable maxillary defects. The frames were supposed to form the infrastructure of the obturator that intends to close the maxillary arch defects. Five main types of maxillary defects according to Aramany classification were selected for this study. 15 different design frameworks were fabricated using Co-Cr dental alloy. The defects were simulated using premade maxillary arch models that were reproduced in photo-elastic resin. The fabricated metal frames were seated on the photo-elastic resin models and then were exposed to standardized stress at 3 different locations on the frames using a global testing machine. A custom made plane polariscope was arranged to provide polarized illumination for the light emission and analysis through the models. The photo-elastic resin models were photographed during loading under the testing machine to display the supporting areas deformation in frontal plane. The results showed that the proposed metallic designs variably distributed the stresses around the abutments and the remaining hard tissues on the photo-elastic models.