Biomechanical Analysis of Various Shapes and Surface Roughnesses of an Immediately Loaded Implant_3D Finite Element Simulation

Abstract

Bone stress and interfacial sliding at the bone-implant interface (BII) were analyzed for an immediately loaded dental implant with various designs and surface roughnesses. 18 finite element models with 4 implant designs and 3 surface roughnesses were created to compare the bone stresses and the sliding at the BII. The material properties of bone model were anisotropic, and a vertical or lateral force of 130 N was applied individually in all models. During lateral loading, the stresses were highly concentrated at one site of the bone. The bone stress and sliding at the BII were highest in the cylindrical implants. The peak stresses in trabecular bone and sliding at the BII were 17-25% and 16-48% lower for the rectangular thread than for the vthread, respectively. The stress in trabecular bone was 15-25% higher for a tapered body design than for a straight body implant. Increasing the surface roughness increased the bone stresses in nonthreaded implants but clearly decreased sliding in both threaded and nonthreaded implants. The conclusions of this study show that using an immediately loaded mandibular implant can induce large bone stresses during lateral loading. Bone stress and sliding at the BII of an immediately loaded implant are heavily dependent on the implant design and surface roughness. For improving the initial interfacial interlocking it suggests that using a threaded implant has a higher priority than using cylindrical designs with a rough surface for an immediately loaded implant.