[Bone resorption at the entry of osseointegrated implants--a biomechanical phenomenon. Finite element study]

Using finite element analysis, osseointegrated implants exposed to physiologic stresses were examined for the occurrence of stress concentrations at the site of implant entry into bone and factors affecting such stress concentrations were looked for. Qualitative and quantitative alterations of stresses around endosseous implants were computed for different implant sizes, implant materials and cortical thicknesses. The following factors were found to be important for reducing peak stresses in cortical bone: Cylindrical implants are preferable to conical implant shapes. Large implant diameters provide for more favorable stress distributions. Implant materials should have a modulus of elasticity of at least 110,000 N/mm2. Slipping between implants and cortical bone is desirable.