Finite element analysis of the influence of implant inclination, loading position, and load direction on stress distribution.

The selection of the appropriate alignment of an implant and the position of implantation are vital for its longterm success. Excessive load is generated around inclined implants, causing microcracks in the bone, which result in implant loosening and eventual failure. This study was designed to analyze the stress distribution caused by varying the degree of inclination of an implant body and varying the loading position and direction, using the finite-element method of stress analysis. Buccal and lingual two-dimensional simulation models of a cylinder implant, embedded in the first molar edentulous cross-section of the mandible, were prepared, and the stress distribution and maximum principal stresses were recorded. Regardless of the point and direction of loading, compressive stresses were relatively greater when the implant was inclined. This tendency became more pronounced when a 45 degrees loading direction and eccentric loading were tested. For the inclined model, with a 45 degrees loading direction, the compressive stress was observed on the cortical bone adjacent to the direction of inclination, while tensile stress was observed on the opposite side.