A comparison of sonically derived and traditional cephalometric values.

The roentgenocephalometric technique is the standard used by orthodontists to assess skeletal, dental, and soft-tissue relationships. However, this technique exposes patients to radiation, preventing orthodontists from taking frequent cephalograms to assess growth and to monitor treatment. Recently, the Dolphin Imaging Company developed the DigiGraph, a nonradiographic cephalometric method that uses sound waves and mathematical algorithms, and consequently does not expose patients to radiation. But the DigiGraph's accuracy as a cephalometric alternative has not been adequately investigated. The purpose of this study was to compare the values obtained by traditional cephalometrics with those obtained by the DigiGraph technique for 30 well-known measurements, and then to assess the repeatability (intraobserver comparison) and reproducibility (interobserver comparison) for both techniques. Eighteen of the 30 measurements had mean differences that were statistically significant (p > .0067). Regression plots generally illustrate low correlations for the measurements, although Ricketts' esthetic line (upper and lower lip) and Steiner's soft-tissue convexity reveal strong linear relationships between the two methods. Additionally, the radiographically generated measurements showed greater repeatability and reproducibility.