Orthodontic appliance

This invention provides an orthodontic appliance of generally U-shaped configuration conforming to the natural arch of the patient, having a flexible outer portion adapted to overlie portions of the facial surfaces on the teeth of a row of teeth, an inner portion of greater rigidity than the outer portion for engaging portions of the lingual surfaces of a row of teeth and overlying the gingiva, and interconnecting portions at the ends of the appliance that fit around the posterior teeth of a row of teeth, with the crowns of the teeth extending upwardly through the opening and unobstructed by the appliance. The surfaces of the inner and outer portions are made to accomplish various tooth movements or tooth retention as desired by appropriately engaging the surfaces of the teeth. Greater degrees of movement may be accomplished by splitting the inner and outer portions and providing resilient members that urge the split segments of the outer portion together and the split segments of the inner portion apart.