Abstract
The purpose of the present study was to develop a screw-incorporated orthodontic bracket to reduce the pain experienced by the patient at debonding and to examine the physical mechanism of its debonding. Debonding is to detach the bonded bracket from the tooth surface when the tip of a mini-screw installed in the bracket base comes out toward the tooth surface by being rotated. This leads to a reduced impact-giving debonding method without the use of debonding pliers. Bond strengths 24 hours after bonding and after 2,000 and 20,000 thermal cycles were examined using a tensile bond strength test, which revealed that the screw bracket has a clinically sufficient bond strength. Light microscopic observation revealed that the detached surface of the bond did not have a uniform topography. The tip of the mini-screw generated a load of 9.11 N on the tooth surface and the mean maximum torque of the mini-screw was 1.89 N・cm.
