Background: To evaluate the effect of bone remodelling around a reduced-diameter dental implant on its fatigue limit using finite element analysis (FEA).
Methods: A dental implant assembly, which included a reduced-diameter dental implant (Biomet-3i external hex), an abutment (GingiHue®) and a connector screw (Gold-Tite Square screw), was scanned using micro-computed tomography (Skyscan 1172). Its dimensions were measured using Mimics (Materialise) and an optical microscope (Keyence). The digital replicas of the physical specimens were constructed using SOLIDWORKS (Dassault Systems). A cylindrical bone specimen holder with two layers (cortical and cancellous bone) was designed in SOLIDWORKS. Two assemblies were created: (a) Model 1: Having non-remodelled bone; (b) Model 2: Cancellous bone remodelled at the regions adjacent to the implant screw threads. FEA was performed in ABAQUS (SIMULIA). In Model 1, the Young's modulus of cortical and cancellous bone were 20 GPa and 14 GPa, respectively. For Model 2, the region of the cancellous bone adjacent to the implant screw threads was assigned a Young's modulus of 20 GPa. fe-safe (SIMULIA) was used to estimate the fatigue limit.
Results: The maximum von Mises stress under 100 N load was 439.9 MPa for both models 1 and 2 and was located at the connector screw. The fatigue limit was 116.4 N for both models 1 and 2.
Conclusions: The results suggest that implant fatigue resistance tested according to ISO 14801 may be accurately predicted without bothering to simulate the non-homogeneous stiffness that occurs at the bone-implant interface in the clinical case.
Keywords: Bone Remodelling; Dentistry; Fatigue Fracture; Finite Element Analysis; Medical Implants; Micro-Computed Tomography.