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

Abstract

Purpose:To assess the retentive force of telescopic crowns using polyetherketoneke-tone (PEKK) high-performance polymer in relation to conventional materials over along period of time in an in vitro setting.Materials and Methods:Thirty-six sets of primary and secondary crowns werefabricated as per the double crown-retained prostheses approach. Six samples wereincluded in each of the five test groups (1: zirconia/PEKK [Zr/PEKK]; 2: tita-nium/PEKK [Ti/PEKK]; 3: cobalt-chrome/PEKK [CoCr/PEKK]; 4: PEKK/PEKK;and 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 sur-face condition was observed. Retentive forces were analyzed using two-way ANOVA(α<0.05).Results:The retention forces in groups Zr/PEKK and Ti/PEKK significantly de-creased over time (group 1:p=0.035 and group 2:p=0.001), whereas retentiveforce increased significantly in groups PEKK/PEKK, Au/PEKK, and control (group4:p=0.001, group 5:p=0.008, and control:p=0.042). Similar wear was observedon the primary crown in groups PEKK/PEKK, gold/PEKK, and control.Conclusions:Groups PEKK/PEKK and Au/PEKK showed a transition of retentiveforce similar to the control group. Groups PEKK/PEKK and Au/PEKK had similarwear on the surface compared to control. Therefore, PEKK has a promising clinicalpotential.