Influence of Placement of Ultrashort Implant at Sub-Crestal, Crestal and Supra-Crestal Level with Titanium or Polyetheretherketone Hybrid Abutment: 3D Finite Element Analysis

The aim of this study was to evaluate and compare the stress concentration of short dental implants supporting different conical abutments using 3D finite element analysis (3D-FEA). A tridimensional model of single-unit short dental implants (5.2 mm x 5 mm) was designed using the computer-aided design (CAD) software based on the manufacturer's stereolithography. The short implants were positioned in a bone model to support titanium or ceramic-reinforced PEEK conical abutments considering different bone levels (supra-crestal, crestal or sub-crestal). With the aid of a computer-aided engineering (CAE) software, the finite element model was created and an axial load of 500 N was applied. Observing the mechanical response of the implant, abutment and screw, both evaluated materials resulted in homogeneous stress and could be indicated for implant-supported restorations with short fixtures. However, aiming to decrease the strain in the bone tissue, placing the implant in the sub-crestal position is a preferable option; while the supra-crestal placement decreases the stress at the screw and implant.