A comparison study of different facial soft tissue analysis methods

ObjectivesThe purpose of this study was to evaluate several different facial soft tissue measurement methods.Materials and methodsAfter marking 15 landmarks in the facial area of 12 mannequin heads of different sizes and shapes, facial soft tissue measurements were performed by the following 5 methods: Direct anthropometry, Digitizer, 3D CT, 3D scanner, and DI3D system. With these measurement methods, 10 measurement values representing the facial width, height, and depth were determined twice with a one week interval by one examiner. These data were analyzed with the SPSS program.ResultsThe position created based on multi-dimensional scaling showed that direct anthropometry, 3D CT, digitizer, 3D scanner demonstrated relatively similar values, while the DI3D system showed slightly different values. All 5 methods demonstrated good accuracy and had a high coefficient of reliability (>0.92) and a low technical error (<0.9 mm). The measured value of the distance between the right and left medial canthus obtained by using the DI3D system was statistically significantly different from that obtained by using the digital caliper, digitizer and laser scanner (p < 0.05), but the other measured values were not significantly different. On evaluating the reproducibility of measurement methods, two measurement values (Ls–Li, G–Pg) obtained by using direct anthropometry, one measurement value (N′–Prn) obtained by using the digitizer, and four measurement values (EnRt–EnLt, AlaRt–AlaLt, ChRt–ChLt, Sn–Pg) obtained by using the DI3D system, were statistically significantly different. However, the mean measurement error in every measurement method was low (<0.7 mm). All measurement values obtained by using the 3D CT and 3D scanner did not show any statistically significant difference.ConclusionThe results of this study show that all 3D facial soft tissue analysis methods demonstrate favorable accuracy and reproducibility, and hence they can be used in clinical practice and research studies.