Use of processed record bases to register edentulous jaw records offers increased accuracy in final prostheses occlusion. Processed bases for the maxillofacial patient following resection of the maxillae or mandible also improve the reliability of the jaw relation record. Because of the unusual paths of insertion and tissue undercuts within the surgical defect, block-out of trial record bases on the master cast can result in gross instability of the bases. Errors in occlusion, esthetics, lip support, and buccolingual tooth placement can be minimized with processed bases.