Evaluation of reproducibility and reliability of 3D soft tissue analysis using 3D stereophotogrammetry

• Published in: International journal of oral and maxillofacial surgery Vol. 38; no. 3; pp. 267 - 273
• Main Authors: Plooij, J.M, Swennen, G.R.J, Rangel, F.A, Maal, T.J.J, Schutyser, F.A.C, Bronkhorst, E.M, Kuijpers–Jagtman, A.M, Bergé, S.J
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-03-2009; Elsevier
• Subjects: 3D stereophotogrammetry; Adult; Aged; Biological and medical sciences; cephalometry; Cephalometry - instrumentation; Cephalometry - methods; computer-assisted three-dimensional imaging; Dentistry; Face - anatomy & histology; Female; Humans; Image Processing, Computer-Assisted; Imaging, Three-Dimensional - instrumentation; Imaging, Three-Dimensional - methods; Male; maxillofacial surgery; Medical sciences; Middle Aged; Observer Variation; orthodontics; Otorhinolaryngology. Stomatology; Photogrammetry - instrumentation; Photogrammetry - methods; Reference Values; reproducibility; Reproducibility of Results; Sensitivity and Specificity; Statistics, Nonparametric; Surgery; Young Adult; maxillofacial surgery; cephalometry; orthodontics; 3D stereophotogrammetry; reproducibility; computer-assisted three-dimensional imaging; Head; 3D stereophoto- grammetry; Stomatology; Maxillofacial surgery; Orthodontic procedures; Reproducibility; Soft tissue; Reliability; Computer aid; Stereophotogrammetry
• ISSN: 0901-5027; 1399-0020
• DOI: 10.1016/j.ijom.2008.12.009

Abstract In 3D photographs the bony structures are neither available nor palpable, therefore, the bone-related landmarks, such as the soft tissue gonion, need to be redefined. The purpose of this study was to determine the reproducibility and reliability of 49 soft tissue landmarks, including newly defined 3D bone-related soft tissue landmarks with the use of 3D stereophotogrammetric images. Two observers carried out soft-tissue analysis on 3D photographs twice for 20 patients. A reference frame and 49 landmarks were identified on each 3D photograph. Paired Student's t-test was used to test the reproducibility and Pearson's correlation coefficient to determine the reliability of the landmark identification. Intra- and interobserver reproducibility of the landmarks were high. The study showed a high reliability coefficient for intraobserver (0.97 (0.90 – 0.99)) and interobserver reliability (0.94 (0.69 – 0.99)). Identification of the landmarks in the midline was more precise than identification of the paired landmarks. In conclusion, the redefinition of bone-related soft tissue 3D landmarks in combination with the 3D photograph reference system resulted in an accurate and reliable 3D photograph based soft tissue analysis. This shows that hard tissue data are not needed to perform accurate soft tissue analysis.