[Horizontal examination of postero-anterior roentgenographic cephalometrics of patients with cross bite and of those without, on mandibular protrusions].

An angular measurement was conducted on 12 cases with cross bite and 18 cases without among the patients who underwent surgical orthodontic treatment for mandibular protrusions (true Class III) and the following results were obtained. 1) An angle measurement for each plane against X axis is helpful for a judgement of facial symmetry. 2) The distortion of each portion (each plane) can be judged from the angular difference of each plane. 3) The angle measurement seems to be useful enough in planning for paper surgery.