Diagnosis and treatment planning of skeletal asymmetry with the submental-vertical radiograph.

The purpose of this study was to assess the reproducibility of landmarks visible in the submental-vertical radiographic projection. Ten subjects with at least a 2 mm apical base discrepancy as diagnosed by means of a posteroanterior headfilm were selected. Mean tracing and measurement error was found to be less than 1 mm for all landmarks. A system of patient orientation and radiographic technique is presented. The radiographs were made at 90 kVp, 15 mA, 1 second exposure, using Kodak Lanex X-D film with a speed of 600. A system of cephalometric analysis is presented for the assessment of skeletal asymmetry in the horizontal plane. This system of analysis uses landmarks within the cranial base, maxilla, and mandible to construct reference lines with which to assess asymmetry. These reference systems allow the assessment of asymmetry within each component part of the craniofacial complex as well as the relative relationship of these parts to one another. Examples are presented to demonstrate the use of this system in assessing skeletal asymmetry. These examples show how this system of analysis can be incorporated into the data base for a particular patient and how it can be useful in making treatment decisions for patients with skeletal asymmetries. This method lends itself to future incorporation into a three-dimensional computerized cephalometric analysis.