Influence of miniscrew sizes on stress distribution

Purpose: The purpose of this study was to evaluate the influence of miniscrew implant diameter and length on the stress distribution in bone and implant using finite element analysis. Materials and Methods: Sixteen finite element models featuring miniscrew implants of various sizes (1.2, 1.4, 1.6 and 1.8 mm in diameter and 6, 8, 10 and 12 mm in length) and surrounding bone were created and loaded with 50 cN force perpendicular to the long axis of the implant in order to investigate resultant stress distribution. Results: Patterns of stress distribution were identical in all models. Stresses were concentrated mainly around the cervical portion of the body of miniscrews. The increase in the miniscrew's diameter resulted in a linear decrease of the stresses values in both the screw and bone, whereas the increase in length of miniscrew showed not significant changes in the stress values. Conclusions: The results of this study suggest that the wider diameter miniscrew implants might ensure a better biomechanical environment for miniscrews. The length of miniscrews did not alter the biomechanical properties of miniscrews inserted in the bone. Keywords: miniscrew implants, orthodontics, anchorage, stress distribution, FEM