【Objectives】
The purpose of study is to evaluate the miniscrew stability with auxiliary skeletal anchorage device using animal model.
【Materials and Methods】
Eleven adult female Japanese white rabbits were used as experimental animals. Twenty conventional miniscrews (non-auxiliary group) and twenty-two miniscrews with auxiliary skeletal anchorage device (auxiliary group) were implanted into the femur of rabbits. The mechanical retention force was compared between auxiliary group and non-auxiliary group at 4 and 8 weeks after implantation, respectively (auxiliary group: 4 weeks n=11, 8 weeks n=11; non-auxiliary group: 4 week n=9, 8 week n=11).
【Results】
The retention forces at 4 and 8 weeks were significantly greater in auxiliary group than in non-auxiliary group at 0.01, 0.02, and 0.03 mm displacements of miniscrew head. The retention force was improved approximately 2.0 to 2.6 times in auxiliary group at each displacement test.
【Discussion】
These results suggested that the novel auxiliary device increases mechanical retention force by enlarging the contact area between miniscrew and bone. Presumably, this auxiliary device should enable the use of a shorter miniscrew instead of a conventional miniscrew because the minimal contact area is compensated for by embedding the spiked portion. And using shorter miniscrew makes it possible to reduce the risk of root proximity and damage. .
【Conclusions】
The novel spike-like auxiliary skeletal anchorage device increases miniscrew stability, and allows a shortened miniscrew thus can minimize risks of root proximity and damage.