An intraoral, flexible, hinged appliance which is an anterior resistance appliance, covering both anterior sextants of both arches (jaws), having the effect of an anterior bite plane, to facilitate orthodontic treatment. Each of the hinged sections consists of a roughly semicircular trough or tray that fits over the anterior sextant of a patient's teeth. The two troughs are hinged at the rear with a flexible material that when the troughs are flexed together and inserted in the mouth causes a force tending to lock the troughs against the patient's teeth, thereby helping to open a deep bite and protect teeth from the negative affects of bruxism or teeth grinding, and to relieve temporomandibular joint pain and dysfunction.