Generic finite element models of orthodontic mini-implants: Are they reliable?

Many finite element (FE) studies used different settings for modeling orthodontic mini-implants (OMIs). This study aims to compare different approaches for modeling OMI with FE method, to exhibit the role of key factors in modeling process. A computerized tomography (CT) dataset of a living human is used to develop subject-specific FE model of bone specimen, and a microCT was used to generate the geometry of OMI. Another five models were developed to assess the effect of changing different settings of FE modeling process. These five models differed from the subject-specific model in either: (i) bone properties' assignment method, (ii) geometries and constrains' conditions, or (iii) simulation method of bone-implant contact (BIC). The models presented significant differences in maximum principal strain distribution. These differences were most apparent when the models differed either in the nature of BIC or the method of assigning bone properties. The models different only in bone geometries showed differences in the intensity of strain rather than its distribution pattern. There is a need for assessment and validation of all FE modeling approaches currently used for simulation of mechanical environment in the bone surrounding OMIs.