Three-dimensional finite element analysis of the stability of mini-implants close to the roots of adjacent teeth upon application of bite force.

To investigate the cause of mandibular implant loss, we evaluated the stress distribution in the bone under bite force when the miniimplant was near the root using three-dimensional finite element analysis. Our analysis involved four finite element models with different distances between the implant and adjacent tooth root and three loading conditions. With loading of the tooth only or both the tooth and implant, the peak stress within the bone around the implant neck, displacement, and stress surrounding the bone near the root increased as the distance between the implant and root decreased. However, with separate loading of the implant, the stress did not correlate with the distance between the implant and root. Application of bite force increases stress within bones surrounding mini-implants near the roots of adjacent teeth and may threaten implant stability, but simple orthodontic loading has little effect on the stress distribution at the mini-implant-bone interface.