Distal movement of maxillary molars using a lever-arm and mini-implant system.

Recently, many studies have been reported on distal molar movement using temporary anchorage devices. However, the side effects of distal movement, such as distal tipping, rotation, or extrusion, are still unsolved. This article describes the use of the lever-arm and mini-implant system for controlled distal movement of maxillary molars and two clinical cases in which patients were treated with this system. Mini implants are needed to control the point of force application in the posterior area with no anchorage loss. When the length of the lever arm and the position of the mini implant are adjusted, the desired line of action of the distal force is determined with respect to the center of resistance of maxillary molars. The lever-arm and mini-implant system is useful not only for absolute anchorage, but also for three-dimensional control during distal movement of the upper molars.