Comparative analysis of numerical and experimental data of orthodontic mini-implants.

The purpose of this study was to compare numerical simulation data derived from finite element analysis (FEA) to experimental data on mini-implant loading. Nine finite element (FE) models of mini-implants and surrounding bone were derived from corresponding experimental specimens. The animal bone in the experiment consisted of bovine rib. The experimental groups were based on implant type, length, diameter, and angle of insertion. One experimental specimen was randomly selected from each group and was digitized in a microCT scanner. The FE models consisted of bone pieces containing Aarhus mini-implants with dimensions 1.5 × 7 mm and 1.5 × 9 mm or LOMAS mini-implants (dimensions 1.5 × 7 mm, 1.5 × 9 mm, and 2 × 7 mm). Mini-implants were inserted in two different ways, perpendicular to the bone surface or at 45 degrees to the direction of the applied load. Loading and boundary conditions in the FE models were adjusted to match the experimental situation, with the force applied on the neck of the mini-implants, along the mesio-distal direction up to a maximum of 0.5 N. Displacement and rotation of mini-implants after force application calculated by FEA were compared to previously recorded experimental deflections of the same mini-implants. Analysis of data with the Altman-Bland test and the Youden plot demonstrated good agreement between numerical and experimental findings (P = not significant) for the models selected. This study provides further evidence of the appropriateness of the FEA as an investigational tool in relevant research.