Comparison between all zirconia, all PEEK, and zirconia-PEEK telescopic attachments for two implants retained mandibular complete overdentures: In vitro stress analysis study

Abstract

Aim: This in vitro study was performed to evaluate and compare stresses applied to the implants retaining mandibular complete overdenture with telescopic attachments of different materials. Materials and Methods: Three identical clear acrylic resin models of completely edentulous mandibular arch were selected for this study. One implant was installed in each canine region of each model. The models were scanned to design telescopic attachment using computer-aided design/computer-aided manufacturing technology. According to material used for telescopic attachments fabrication, models were categorized as follows: All Zirconia (ZrO2) telescopic group (zz): Primary and secondary crowns were made of ZrO2, all polyetheretherketone (PEEK) telescopic group (pp): Primary and secondary crowns were made of PEEK, and Zirconia-PEEK telescopic group (zp): Primary crown was made of ZrO2, and secondary one was made of PEEK. Three identical mandibular complete overdentures were constructed. The secondary telescopic crowns were picked up within the intaglio surface of each overdenture. Four strain gauges were installed parallel to each implant. Bilateral and unilateral loads were applied, and strain values were recorded. Results: Comparison of recorded stresses values revealed a significant difference between groups where the highest stresses were recorded with all-PEEK group, followed by all-zircon group and the lowest stresses were noted with Zirconia-PEEK group for both bilateral and unilateral loading tests. Conclusion: Within the limitation of this in vitro study, it could be concluded that: telescopic attachments that fabricated from ZrO2 primary crown and PEEK secondary crown is a promising attachment regarding reductions of stresses transmitted to the implants retaining mandibular complete overdenture.