<XML><RECORDS><RECORD><REFERENCE_TYPE>0</REFERENCE_TYPE><REFNUM>7489</REFNUM><AUTHORS><AUTHOR>Hajeer,M.Y.</AUTHOR><AUTHOR>Mao,Z.</AUTHOR><AUTHOR>Millett,D.T.</AUTHOR><AUTHOR>Ayoub,A.F.</AUTHOR><AUTHOR>Siebert,J.P.</AUTHOR></AUTHORS><YEAR>2004</YEAR><TITLE>A new three-dimensional method of assessing facial volumetric changes following orthognathic treatment</TITLE><PLACE_PUBLISHED>the American Journal of Cleft & Craniofacial Surgery </PLACE_PUBLISHED><PUBLISHER>N/A</PUBLISHER><LABEL>Hajeer:2004:7489</LABEL><KEYWORDS><KEYWORD>3D imaging</KEYWORD></KEYWORDS<ABSTRACT>Objective: To validate a new method of facial volumetric assessment which is dependent on the use of stereophotogrammetric models and a software-based Facial Analysis Tool. Design: The method was validated in vitro using 3D models of a life-like plastic female dummy head and in vivo using a male subject head. Methods: Thirty facial silicone explants were added in the nasal and perioral regions of each head and their volumes were obtained using three different algorithms. These were compared to the actual values obtained by a ‘water displacement’ method. Results: The least mean error was found with the ‘tetrahedron formation’ method followed by the ‘projection’ method and the ‘back-plane construction’ method. The error with the ‘tetrahedron’ method was 0.071 cm3 (95% CI: -0.074 – 0.2161 cm3) and 0.314 cm3 (95% CI: -0.080 - 0.708 cm3) using the in vitro and the in vivo models, respectively. The increased volumetric assessment error observed in vivo was attributed to the registration procedure and possible changes in facial expression. Conclusions: These results encourage the use of this method in the 3D assessment of orthognathic surgical outcome, provided a standardised facial expression is used for image acquisition. </ABSTRACT></RECORD></RECORDS></XML>