Impact of CT image resolution and material modeling on biomechanical predictions at the bone-implant interface

The Finite Element Method (FEM) is a cornerstone of biomechanical analysis in dental implantology. However, the accuracy of FEM predictions is highly dependent on the underlying model, particularly the resolution of the input computed tomography (CT) images and the assigned material properties. A lack of standardized guidelines creates uncertainty about how these modeling choices affect outcomes, hindering the comparison of results across studies. This study aims to systematically quantify the impact of CT image resolution and material model selection on the predicted biomechanics of a bone-implant system.

Twenty-three computational models of a dental implant within a human mandible segment were developed and analyzed. The models were based on three micro-CT scan resolutions and featured two different geometric representations of cancellous bone. A range of material properties was assigned, including both homogeneous and non-homogeneous (density-based) Young's moduli. Peri-implant bone strain distribution, maximum implant stress, and displacement were evaluated.

Principal Component Analysis demonstrated a clear segregation of models into distinct clusters, primarily driven by the geometric representation (trabecular vs. non-trabecular) and secondarily by image resolution. Low-resolution (150 µm) trabecular models predicted substantially higher strains and displacements than high-resolution (30 and 60 µm) models. Axial displacement values of the dental implant ranged from 8 to 22 µm in the 30 µm models and from 19 to 55 µm in the 150 µm models, while stresses ranged from 161 to 164 MPa and from 196 to 226 MPa, respectively. Notably, simplified non-trabecular models with non-homogeneous material properties could approximate the strain distributions of some complex trabecular models, but failed to accurately predict implant stress.

There is no single "best" model; the optimal choice must be tailored to the specific research question. While high-resolution trabecular models provide the most comprehensive data, simplified non-trabecular models can be an efficient alternative for bone strain analysis. However, they are inadequate for predicting implant stress. These findings provide a crucial framework for developing standardized, application-specific modeling protocols in dental implantology.