Objective: To evaluate the influence of autoclave sterilization on the fracture torque of five commercially available mini-implants used for orthodontic anchorage.
Design: In vitro laboratory study.
Materials and methods: Ten mini-implants from each of five different manufacturers were submitted to one cycle of autoclave sterilization and tested, compared to their control groups - consisting of 10 as-received mini-implants each - to assess their fracture torque values. The mini-implants, connected to a digital torque gauge perpendicularly positioned to the bone surface, were inserted into swine femoral cortical bone segments until their fracture.
Outcome measures: Maximum torque values.
Statistical analysis: A two-way ANOVA to detect differences between implant products and the allocation group and one-way ANOVA with the Tukey's honestly significant difference (HSD) post hoc test among autoclaved groups and among control groups separately to detect differences between manufacturers.
Results: The effect of the autoclaving process was not significant (P = 0·411). The manufacturer factor, however, was significant (P < 0·001). The one-way ANOVA with the Tukey's HSD post hoc test results showed statistically significant differences between control groups.
Conclusion: The autoclave sterilization of the mini-implants tested in this study did not affect their resistance to fracture; however, the mini-implants from different manufacturers presented with statistically significant differences in their resistance to fracture.