The aim of this study was to compare the surface morphology and fracture torque resistance of as-received, sterilized and retrieved mini-implants in order to evaluate the fracture risks of re-using orthodontic mini-implants after sterilization. Thirty mini-implants retrieved from 19 patients, twenty as-received and twenty autoclaved mini-implants from the same manufacturer were used in this study. Ten samples from each group were analyzed by scanning electron microscopy and the remaining specimens were tested for their fracture torque resistance. Results were statistically analyzed using one-way ANOVA. No defects or corrosion could be identified in autoclaved and retrieved mini-implants, but a worn surface and scratch marks could be observed on the retrieved ones. A statistical significant difference in the fracture torque was observed between the as-received and the retrieved groups. Re-use of retrieved mini-implants should not be recommended because their torque resistance is reduced. As-received mini-implants submitted to autoclave sterilization can be recommended to be used clinically.
implant fracture; re-use; Scanning Electron Microscopy (SEM); sterilization
