A forsus appliance is 3M Unitek’s Class II corrector. Seventy percent of Class II relationships are due to a mandibular retrusion. There are many appliances to help the orthodontist advance the mandible. A herbst appliance is my appliance of choice for severe mandibular retrusions and can be placed at the beginning of treatment. A forsus appliance is a little more patient friendly and is used for Class II correction’s that are not quite as severe. It can also be used as a fixed Class II corrector when a patient does not wear elastics. The forsus appliance is usually placed about 10 to 14 months into treatment. If we are concerned with catching the growth spurt the forsus can be used at the start of treatment as a crossbow appliance. There are many variations and ways to wear a forsus to give intrusion or a headgear effect as well.