[Morphology of the upper arch in unilateral posterior crossbite]

The Authors have studied 81 patients, age 4 to 14 years, who exhibit unilateral posterior cross-bites. In the study it was found that the morphology of the maxillary arch can be symmetrical, contracted or expanded on the side of the cross-bite. Of the symmetrical maxillary arches, 79.3% occluded with a mandibular arch on symmetrical bone. Of the arches constricted on the side of the cross-bite, 81.0% occluded with a mandibular arch on asymmetrical bone. Of the arches expanded on the side of the cross-bite, 81.0% occluded with a mandibular arch on asymmetrical bone. From this study we can also say that it is possible to obtain diagnostic data concerning the morphology of the mandibular bone from the morphology of the maxillary arch. Statistical analysis of these data reveals this to be particularly true when the maxillary arch is expanded on the side of the cross-bite.