الفهرس | Only 14 pages are availabe for public view |
Abstract This simulation study was conducted to evaluate the stresses induced by Thermoflex framework in comparison to chrome cobalt framework on the supporting structures of Kennedy class I removable partial denture retained with extra-coronal, semi-precision attachments. Acrylic mandibular model with the first and second premolars bilaterally as abutment teeth was used for this study. This model replicates the anatomic features of the teeth and their investing structures. The abutments were reduced to 1.5-2 mm off occlusal to provide sufficient tooth reduction with 6 degree taper. The metal crowns with the male part of the extra coronal attachment were fabricated according to conventional casting techniques. Then the chrome-cobalt class I RPD with the female part of the extra-coronal attachment was constructed similarly. Thermoflex RPD was constructed with the same design as chrome cobalt framework according to manufacturer instruction. Two four channel strain meters were used to asses and record the strains induced at the second premolars bilaterally. Strain gauges were installed in a groove created distal to the sockets of the 2nd premolars. A loading device was used to produce a standardized static load within the physiologic limits of 100 N on the first molar area unilaterally. Micro strains were recorded at each site of the strain gauges during posterior unilateral loading with enough time between each load to permit complete rebound of the resilient structures. Inspection of the recorded micro strains of the result of this study revealed that, stresses induced distal to the abutments (2nd premolars) during unilateral loading when using thermoflex framework, with extra-coronal attachments were significantly higher than when using the metal framework retained with attachments. |