Introduction: RPD for class II takes support from teeth and tissue of edentulous span of different compressibility .Prosthetic management concerns not only restoring the missing spans but also protection of remaining teeth and bone along with a healthy soft tissue. Digital technology and recent polymer material such as Polyether ether ketone (PEEK) and poly ether ketone ketone (PEKK) are used for fabrication of RPD with superior esthetics. The aim of this study: to evaluate the fracture resistance and stress induced by polyether ether ketone (PEEK) versus polyether ketone ketone (PEKK) used in extra coronal attachment of partial denture in Kennedy class II.Materials and methods: Printed 3D lower resin class II model with detachable dies was used to design two splinted crowns with extra coronal attachment virtually. Each of the study groups :group (A) PEEK and group (B) PEKK had 22 milled splinted crowns with extra coronal attachment and partial denture .load was applied bilaterally and stress analysis and fracture resistance were recorded. Data were collected & statistically analysed to compare both groups by independent t-test, the p-value was considered significant at the level of <0.05.
Results:The two studied groups showed statistically significant where strain induced was reduced in group (B) in compared to group(A) Conclusion: With in the limitation of this study PEKK material express better distribution of strain & better mechanical properties in compare to PEEK