Retention and Surface Roughness of Polyetherketoneketone (PEKK) Vs. Acetal Resin Framework in Kennedy Class IV Removable Partial Dentures: An In Vitro Study

Aim of study : to evaluate retention & surface roughness of PEKK & Acetal Resin frameworks in Kennedy class IV RPD. Materials and methods: Twelve partial denture frameworks were constructed for this study, acrylic resin (AR) model of Kennedy class IV maxillary arch was constructed & RPD design was established. Abutment preparations were made; digital scanning & RPD framework was virtually designed in 3D format. The STL file was transferred to 5-axis milling machine for milling the PEKK blanks producing PEKK frameworks. For acetal resin frameworks, the STL file was used to print an AR 3D printed framework which was flasked, after which the acetal resin frameworks were produced by injection molding technique. A Universal testing machine was used to evaluate retention of RPD frameworks at different simulated time intervals. The surface roughness of the RPD frameworks were evaluated using 3D optic profilometer at a fixed selected area in all frameworks. Results: The PEKK partial denture framework showed statistically insignificant higher mean values compared to acetal resin at baseline, 3 & 6 months. A significant difference was noticed at the 1, 1.5, 2, 2.5 & 3 year cycles. There was an insignificant difference between the surface roughness of the PEKK & acetal resin frameworks. Conclusion: Within the limitations of this study, it can be concluded that the PEKK may provide significantly better retention compared to acetal resin in Kennedy Class IV partial denture frameworks. However, both materials showed an insignificant difference regarding their surface roughness.