To compare the initial stability difference between a new designed torque-resisted orthodontic miniscrew anchorage and commercial miniscrew anchorage by torque tests and resonance frequency analysis (RFA).

After predrilled 4 mm-deep holes with a diameter of 1. 0 mm, two different miniscrews were implanted into the swine ribs for measurement of maximum insertion torque (MIT), maximum removal torque (MRT) and RFA which was recorded as implant stability quotient (ISQ). Statistical analysis was done for all data by SPSS 13. 0.

The mean value of MIT, MRT, ISQ for new miniscrews were (11. 86 ± 1. 58) N·cm, (8. 45 ± 2. 24) N· cm and 61. 80 ± 2. 9 while for commercial miniscrews were (10. 36 ± 1. 42) N·cm, (6. 76 ± 1. 78) N·cm and 58. 15 ± 2. 98. The differences between the two miniscrews were statistically significant (P ＜ 0. 05).

The torque-resisted miniscrews were more stable than commercial miniscrews.