The narrowing of the maxillary arch caused the mandibular displacement. The succedaneous teeth erupt and intercuspate to positions of the displacement. The incisal interference was created by the maxillary incisors being too upright, too far to the lingual, blocking the maxillary cuspids.
Initial x-rays show blocked maxillary cuspids
Orthodontic treatment changed the faulty intercuspation of the teeth that were dominant and intrusive into the free-way space thereby directing the retrognathic mandible, to passive tooth position that permitted normal closure from a normal rest position without condylar displacement.