Peak torque values at fracture of orthodontic miniscrews.

JCO/JUNE 2007 T orthodontic miniscrews have become increasingly popular as a means of providing skeletal anchorage for tooth movement.1,2 If miniscrew anchorage is to be successful, however, the mechanical lock (torque) of the screw in the bone must be able to withstand the applied force.3 A selfdrilling miniscrew is inserted directly through the gingival or oral mucosa into bone; a non-selfdrilling miniscrew is inserted through a pilot hole that has been drilled into the bone with a bur. Previous clinical studies have investigated the torque values (strength) of various orthodontic miniscrews during insertion or removal.4,5 The present study was undertaken to investigate the peak torque values at fracture of five commonly used, FDA-approved miniscrews in vitro.