The main goal of two phase Class II treatment is to decrease the need for full fixed appliances or at least decrease the treatment time in phase two in order to reduce root resorption and decalcification. The end of phase one goal for Xbow treatment is Class I first bicuspids which can be consistently achieved. Xbow treatment takes approximately 4 to 6 months unless compensatory maxillary expansion is necessary which adds about 6 months. The second phase, if necessary, usually takes about 12 to 18 months. Duncan will describe the basics of Xbow treatment with examples of treated cases. He will also review the Xbow study which was published in the AJO-DO.