Determination of the accuracy and consistency of the DigiGraph Work Station in two and three dimensions

Abstract

The DigiGraph Work Station (DWS) (Dolphin Imaging Systems, Valencia, CA) acquires three-dimensional data by using sonic digitization, potentially eliminating the need of diagnostic radiation for orthodontic treatment planning. The difference in time it takes for the sounds emitted from a hand held digitizing probe to be received by microphones, combined with probe geometry, is used to calculate the location of the probe tip in three-dimensional space. The accuracy and consistency of this system with itself has not yet been verified. The objective of this investigation was to establish the two-dimensional and three-dimensional accuracy and consistency of point location determination of this system, under various environmental conditions, sound emitter positions, and for obtaining linear and angular measurements. The accuracy and consistency of the DWS were greatest when in an environment of normal temperature and sound, and void of any air currents. Air turbulence, even a minimal amount, produced statistically significant differences. The DWS changed in accuracy and consistency in determining a point location when the digitizing probe was oriented in various positions and angles. The 2-D linear and angular measurements of the DWS were inconsistently accurate. The DWS's capability to record 3-D linear measurements was overwhelmingly inaccurate and inconsistent when compared with itself. It is suggested that the DWS be used in a spacious and isolated area that has proper acoustical absorption and is void of air currents. The DWS has limited usefulness for definitive diagnostic and treatment planning purposes due the inaccuracy and inconsistency.