A comparison of threedimensional photogrammetric analysis of the face with traditional cephalometric measurements

Abstract

Spatial reconstruction based on two-dimensional photographs is a method to obtain 3D images which does not require high equipment investments. The third dimension is obtainable by taking additional photographs of an object from several angles according to a scheme allowing to determine a specific perspective and their relative location towards others in a precise way. <b>Aim</b>. To assess precision of the author’s photogrammetric method for three-dimensional facial reconstruction (3D). To compare results of cephalometric analyses on X-ray scans with photogrammetric threedimensional facial reconstruction. <b>Material and methods.</b> The study was performed based on components of routine medical documentation of 57 orthodontic patients (21 males and 36 females, mean age 18.2 years (9.9–45.3 years). Right-face cephalometric radiographs and right-, full-, and left-face digital photographs were analyzed in the studies. All photographs were taken with a mobile photostatic station. Photographs were taken when a patient assumed a sitting position with natural head orientation (NHO). With regard to a laboratory stage, all photographs were cataloged appropriately and then they were calibrated, idealized, and spatially reconstructed (3D). <b>Results.</b> With regard to a 3D facial reconstruction method a mean difference of measurements was 0.45 mm and the standard deviation was 0.38 mm. Precision (repeatability) for five linear measurements of the face was 0.53 mm (SD = 0.46 mm), and for angular measurements the precision was 0.6° with the standard deviation of 0.49°. Results of the correlation analysis showed that the mean correlation coefficient (r) for six angular measurements was 0.79. The correlation coefficient between measurements performed using both cephalometric methods was statistically significant (p = 0.0000). Conclusions. The authors’ system of photogrammetric 3D facial reconstruction is an effective cephalometric tool. 3D photogrammetric facial reconstruction may be used when planning orthodontic treatment. <b>(Tsynkel P, Woźniak K. A comparison of three-dimensional photogrammetric analysis of the face with traditional cephalometric measurements. Orthod Forum 2017; 13: 141-52).</b>