Bio-HPP versus Co-Cr, CAD/CAM designed Telescopic retained Removable Partial Dentures (In vitro study)

Abstract

• An educational maxillary stone model representing Kennedy class I was used for this study. • Virtualization of the cast and creation of a digital model with removable dies after reduction of the abutment teeth was done. • Spaces for the soft tissue simulating material were provided representing the mucosa over the crest of ridge and grooves were created for strain gauge sensors. • Printing of 12 models and seating of the abutments was verified and soft tissue simulating material was injected to fill the spaces. • Telescopic retained RPD was digitally designed, using Exocad software. • 12 copies of Telescopic RPD were milled to comprise 2 groups. • In group I, 6 telescopic retained RPDs were milled out of fully sintered CoCr blanks, and Group II 6 telescopic retained RPDs were milled out of BioHPP blocks. • The frameworks were scanned and superimposed on the original design STL file to detect the accuracy of manufacturing. • Then artificial teeth were set on the frameworks, then they were mounted on the chewing simulator for 60000 cycles and then the primary copings were scanned and superimposed with the STL file of primary coping file, surface deviations denoting the amount of wear were recorded for each sample. • Strain gauge sensors were installed and the RPDs were subjected to loading of 100N and strain levels were recorded. • Comparisons between results of the 2 groups were done.