Misinterpreting growth and treatment outcome from serial cephalographs.

This communication addresses the issue of interpretation of serial cephalometric records. Angular measurements provide information that combines the vertical and sagittal components of a landmark's displacement. For example, a decrease in the SNA angle following orthodontic treatment with a headgear demonstrates maxillary retraction relative to nasion, an important assessment to depict a change closely related to the facial profile. Upon superimposition on the anterior cranial base, however, the vertical movement of point A may be the prevalent displacement, which would still account for the decrease in the SNA angle. The superposition allows the evaluation of the displacement in its vertical and sagittal components separately, relative to a structure that is relatively more stable than nasion. The superimposition enhanced the precision of the information regarding the actual displacement of the jaw. A patient's cephalometric records are presented, further demonstrating that the interpretation of changes during growth and treatment should be based not only on angular measurements, but also on regional superpositions. The frames of reference of both procedures are needed to fully understand the facial changes.