 The frictional resistance between a stainless steel arch wire and a bracket was calculated, and the effects of cyclical displacement forces on frictional resistance were tested. With repeated displacement forces applied to the arch wire, the force required to slide the wire through the bracket was reduced, and the percentage reduction depended on the size of the displacement force. The clinical implications for different types of orthodontic brackets remain unresolved. As frictional resistance in the mouth may not be accurately reflected by steady mode laboratory models. This article was authored by UCF, Broadcast P, and FreerTJ.