Double-Crown Prosthesis Retention using Polyetherketoneketone (PEKK): An In Vitro Study.

PURPOSE To assess the retentive force of telescopic crowns using polyetherketoneketone (PEKK) high-performance polymer (HPP) in relation to conventional materials over a long period of time in an in vitro setting. MATERIALS AND METHODS Thirty-six sets of primary and secondary crowns were fabricated as per the double crown-retained prostheses approach. Six samples were included in each of the five test groups (1: Zirconia/PEKK [Zr/PEKK]; 2: Titanium/PEKK [Ti/PEKK]; 3: Cobalt-chrome/PEKK [CoCr/PEKK]; 4: PEKK/PEKK; 5: Gold/PEKK [Au/PEKK]) and the single control group (Gold/Galvano-gold [Au/GA]). The insertion-removal test was performed for 20,000 cycles, and the surface condition was observed. Retentive forces were analyzed using two-way ANOVA (α