Impact of Different Digital Fabrication Techniques of Substructure Materials on Stress Distribution in all-on-4 Mandibular Restorations. A Finite Element Analysis

Abstract

Statement of the problem: All-on-four concept is used as an outstanding choice for edentulous
patients. Framework characteristics of such restoration play a crucial role in its long-term success,
affecting all aspects from biomechanical stability through osseointegration to patient satisfaction.
Study aim: Utilizing finite element analysis (FEA) to investigate the biomechanical performance of
different framework materials with solid conventional geometry and topographically optimized ones,
as a substructure of all-on-four restorations. Materials and methods: A 3D model was created. The
framework materials were Titanium, and Titanium Dioxide- reinforced PEEK (TiO2-PEEK)
fabricated by 3D printing, one conventional, and one with optimized topography. Deformation and
stress were assessed under vertical and oblique loads. Results: No failure occurred in any component.
Titanium absorbed high internal stress with less stress transferred to model components, but TiO2- PEEK underwent minimal internal stress with high stress on the model components. Topology optimization contributed to redistribution of structural stress, mitigating peak stress concentrations at critical cantilever junctions and minimizing excessive deformation. Conclusion: The tested materials
and designs were found to be competent as all-on-four frameworks. Optimized topography offered excellent biomimetic compromise for both selected materials, avoiding the structural stress peaks of rigid metal designs while protecting the peri-implant bone from the excessive strains associated with standard flexible polymers.