Orthodontists have used functional appliances for more than 100 years. Myofunctional Appliances are fixed or removable orthodontic appliances which use forces generated by stretching of muscles, fascia and/or periodontium to change skeletal or dental relationship. There are various indications and designs of functional appliances. The most common indication is to correct Class II malocclusion by posturing the mandible forward in growing patients in an attempt to utilize the individual's growth potential. This book covers Myofunctional Appliances in detail including history, classification, treatment options and recent advances.