Micromotion of Immediately Loaded Zirconia Dental Implants for Various Parametric Conditions: A Three-Dimensional Finite Element Study

Excessive micromotion may cause failures in osseointegration between the implant and bone. This study investigated the influence of various mechanical parameters on micromotion at the boneimplant interface for Zirconia dental implants in three dissimilar bone qualities (type II, type III, and type IV) under immediate loading conditions. A three-dimensional finite element model of a dental implant and bone block was developed and implemented for determining micromotion in terms of relative displacement at the bone-implant interface. Finite element simulations were conducted for different implant thread designs and loading direction. Results of this study suggest that the vertical displacement is sensitive to implant thread design and loading direction. Under the application of a vertical load, the displacement had a positive correlation with thread pitch and helix angle and a negative correlation with thread compactness. The implant stability was restricted in type II bone and it was increased in type III and type IV bone under the influence of horizontal loading for all the cases considered. The cancellous bone density, when compared to the cortical bone thickness, had less influence on micromotion at the bone-implant interface. The influence of thread patterns on micromotion was varied in accordance with the bone type.