# Three-dimensional finite element analysis of tooth and implant-supported telescopic prosthesis using zirconia, PEKK, and cobalt chromium crowns

## TL;DR

This study used 3D modeling to compare how different crown materials affect stress in tooth-implant-supported dental prostheses.

## Contribution

The study introduces a 3D FEA comparison of zirconia, PEKK, and Co-Cr materials in telescopic prosthesis configurations.

## Key findings

- PEKK as a secondary crown reduces stress in prosthetic components but increases stress on supporting structures.
- Zirconia and Co-Cr showed similar biomechanical behavior across all configurations.
- Secondary crowns consistently showed higher stress than primary crowns, and implants experienced greater loads than natural teeth.

## Abstract

This study aimed to evaluate the biomechanical behavior and stress distribution of tooth–implant-supported telescopic prostheses using different combinations of zirconia, polyetherketoneketone (PEKK), and cobalt–chromium (Co-Cr) materials for primary and secondary crowns by means of three-dimensional finite element analysis (3D FEA).

A three-dimensional finite element model representing a mandibular arch restored with a telescopic overdenture supported by two canines and two implants in the molar region was constructed. Nine prosthetic configurations were analyzed based on different primary and secondary crown material combinations (zirconia, PEKK, and Co-Cr). All materials were assumed to be homogeneous, isotropic, and linearly elastic. Static axial occlusal loads simulating centric occlusion were applied. Von Mises stress distribution was evaluated in prosthetic components, implants, natural teeth, and surrounding bone.

Material selection significantly influenced stress distribution within the telescopic system and supporting structures. PEKK used as a secondary crown reduced stress concentrations within the prosthetic crowns but resulted in increased stress transfer to the supporting bone, teeth, and implants compared with zirconia and Co-Cr. When PEKK was used as a primary crown, stress levels within prosthetic components were reduced, while stress transmission to supporting structures was not substantially altered. Zirconia and Co-Cr demonstrated comparable biomechanical behavior across all configurations. In all models, secondary crowns exhibited higher stress values than primary crowns, and implants were subjected to greater loads than natural teeth.

Within the limitations of this 3D finite element study, material combinations in tooth–implant-supported telescopic prostheses significantly affect biomechanical stress distribution. PEKK exhibits a material-dependent stress-modulating behavior that should be carefully considered during prosthetic design to balance prosthetic protection and load transfer to supporting structures.