This article presents the characteristics and roles of dental hygienists in the Department of Orthodontics at Matsumoto Dental University. The presence of a fixed orthodontic appliance makes tooth cleaning more difficult and facilitates plaque build-up. Orthodontic patients are thus counseled and treated by hygienists before placement of the orthodontic appliance and are instructed in tooth brushing techniques during orthodontic treatment. In our clinic, additional roles of hygienists are to provide tooth brushing instructions (T.B.I.) and myofunctional therapy (MFT). Hygienists practice T.B.I, with various devices. Utilization of MFT to correct adverse oral habits during the treatment of malocclusion can be of value to the practicing orthodontist. This approach is also useful for achieving more complete treatment results and preventing post-orthodontic relapse. We also describe the contents ofMFT as practiced by hygienists in our clinic.