Finite element analysis of post dental implant fixation in drilled mandible sites.

BACKGROUND: Implant loosening may occur after dental implant placement as a result of the mechanical conditions created around the implant. In this research, the effect of bone drilling conditions on the magnitude of stress created in newly-formed bone around the implant, after placement, was investigated using FEA analysis.

METHOD: The simulations performed in this study were based on the three-dimensional (3D) shape of the created cavities, extracted from the drilled cortical bone of the jaws. With this aim, a dental implant model was placed in the jaw and a shell of the 3D bone cavity remained as a newly-formed cortical bone after implant placement. Then, a load was exerted on the implant model and the value of stress created on the newly-formed bone was obtained. Overall, eight combined models were used in all the eight drilling and loading simulations. The examined variables were rotational speed of drill bit, its feed rate and head angle. Also, an animal test was performed to investigate the accuracy of the simulation results.

RESULTS: The results of this study showed that the amount of principal stress was the least (16.7MPa) for a newly-formed cortical bone whose cavity was created under drilling condition at the same head angle and feed rate of the drill bit with a rotational speed of 400rpm. The same results were obtained for the head angle and feed rate of a drill bit of 70° and 1.5mm/s, respectively.

CONCLUSIONS: Drilling conditions have effect on the stress created in a newly-formed cortical bone after dental implant loading.