Stress Evaluation of Indirect Composite Superstructure on Different Copings in CAD-on Technique for Restoration of Titanium Dental Implants—3D Finite Element Analysis

Abstract

The aim of the study is to evaluate and compare the stress distribution and total deformation of indirect composite veneered superstructures fabricated using different coping materials—zirconia, biocompatible high-performance polymer (BioHPP), and polyetherketoneketone (PEKK)—via the CAD-on technique using three-dimensional (3D) finite element analysis.

A 3D finite element model of a mandibular second premolar restored with a 4.1 × 12 mm titanium implant and internal hex abutment was digitally reconstructed. Four restorative configurations were analyzed: (G1) zirconia coping with hand-layered ceramic veneer, (G2) zirconia coping with HIPC veneer, (G3) BioHPP coping with HIPC veneer, and (G4) PEKK coping with HIPC veneer. Models were developed in ANSYS Workbench 2022 R2 and subjected to a static vertical load of 280 N applied over the occlusal surface. Von Mises stress and total deformation were measured at the coping, abutment, and implant interfaces. Data were analyzed using one-way ANOVA (Analysis of Variance) and Tukey's post-hoc test (α = 0.05).

The highest stress occurred in G1 (29.62 ± 37.73 MPa) at the implant margin, while the lowest values were noted in G3 (13.05 ± 9.63 MPa at the coping; 14.13 ± 2.06 MPa at the abutment). Total deformation differed significantly among groups (p <0.05), with G4 showing the least deformation (0.78 ± 0.02 mm) at coping level and G3 demonstrating minimal deformation at the implant abutment (0.78 ± 0.02 mm).

Polymer-based CAD-on restorations, especially BioHPP and PEKK copings veneered with HIPC, exhibited superior stress modulation and lower deformation compared to zirconia-based systems. These findings suggest that flexible polymeric copings provide more biomechanically favorable load transfer, supporting their use as resilient alternatives for implant-supported prostheses.