Maggie K Grissom1, Jaime Gateno2, Jeryl D English3, Helder B Jacob4, Tianshu Kuang5, Carla E Gonzalez6, Peng Yuan7, Hannah H Deng8, Caleb J Frick9, Daeseung Kim8, Abdullahi Hassan10, James J Xia11. 1. Former Resident, Department of Orthodontics, The University of Texas Health Science Center at Houston School of Dentistry, Houston, TX. 2. Chairman and Professor, Department of Oral and Maxillofacial Surgery, Houston Methodist, Houston, TX; Professor of Clinical Surgery (Oral and Maxillofacial Surgery), Weill Medical College, Cornell University, New York, NY. 3. Chairman and Professor, Department of Orthodontics, The University of Texas Health Science Center at Houston School of Dentistry, Houston, TX. 4. Assistant Professor, Department of Orthodontics, The University of Texas Health Science Center at Houston School of Dentistry, Houston, TX. 5. Research Assistant, Department of Oral and Maxillofacial Surgery, Houston Methodist Research Institute, Houston, TX. 6. Former Research Assistant, Department of Oral and Maxillofacial Surgery, Houston Methodist Research Institute, Houston, TX. 7. Former Research Associate, Department of Oral and Maxillofacial Surgery, Houston Methodist Research Institute, Houston, TX. 8. Research Associate, Department of Oral and Maxillofacial Surgery, Houston Methodist Research Institute, Houston, TX. 9. Former Resident, Department of Orthodontics, The University of Texas Health Science Center at Houston School of Dentistry, Houston, TX; Major and Staff Orthodontist, The United States Air Force. 10. Former Fellow, Department of Oral and Maxillofacial Surgery, Houston Methodist Hospital, Houston, TX. 11. Professor of Oral and Maxillofacial Surgery, and Director of Surgical Planning Laboratory, Houston Methodist, Houston, TX; Professor of Surgery (Oral and Maxillofacial Surgery), Weill Medical College, Cornell University, New York, NY. Electronic address: JXia@HoustonMethodist.org.
Abstract
PURPOSE: A facial reference frame is a 3-dimensional Cartesian coordinate system that includes 3 perpendicular planes: midsagittal, axial, and coronal. The order in which one defines the planes matters. The purposes of this study are to determine the following: 1) what sequence (axial-midsagittal-coronal vs midsagittal-axial-coronal) produced more appropriate reference frames and 2) whether orbital or auricular dystopia influenced the outcomes. METHODS: This study is an ambispective cross-sectional study. Fifty-four subjects with facial asymmetry were included. The facial reference frames of each subject (outcome variable) were constructed using 2 methods (independent variable): axial plane first and midsagittal plane first. Two board-certified orthodontists together blindly evaluated the results using a 3-point categorical scale based on their careful inspection and expert intuition. The covariant for stratification was the existence of orbital or auricular dystopia. Finally, Wilcoxon signed rank tests were performed. RESULTS: The facial reference frames defined by the midsagittal plane first method was statistically significantly different from ones defined by the axial plane first method (P = .001). Using the midsagittal plane first method, the reference frames were more appropriately defined in 22 (40.7%) subjects, equivalent in 26 (48.1%) and less appropriately defined in 6 (11.1%). After stratified by orbital or auricular dystopia, the results also showed that the reference frame computed using midsagittal plane first method was statistically significantly more appropriate in both subject groups regardless of the existence of orbital or auricular dystopia (27 with orbital or auricular dystopia and 27 without, both P < .05). CONCLUSIONS: The midsagittal plane first sequence improves the facial reference frames compared with the traditional axial plane first approach. However, regardless of the sequence used, clinicians need to judge the correctness of the reference frame before diagnosis or surgical planning.
PURPOSE: A facial reference frame is a 3-dimensional Cartesian coordinate system that includes 3 perpendicular planes: midsagittal, axial, and coronal. The order in which one defines the planes matters. The purposes of this study are to determine the following: 1) what sequence (axial-midsagittal-coronal vs midsagittal-axial-coronal) produced more appropriate reference frames and 2) whether orbital or auricular dystopia influenced the outcomes. METHODS: This study is an ambispective cross-sectional study. Fifty-four subjects with facial asymmetry were included. The facial reference frames of each subject (outcome variable) were constructed using 2 methods (independent variable): axial plane first and midsagittal plane first. Two board-certified orthodontists together blindly evaluated the results using a 3-point categorical scale based on their careful inspection and expert intuition. The covariant for stratification was the existence of orbital or auricular dystopia. Finally, Wilcoxon signed rank tests were performed. RESULTS: The facial reference frames defined by the midsagittal plane first method was statistically significantly different from ones defined by the axial plane first method (P = .001). Using the midsagittal plane first method, the reference frames were more appropriately defined in 22 (40.7%) subjects, equivalent in 26 (48.1%) and less appropriately defined in 6 (11.1%). After stratified by orbital or auricular dystopia, the results also showed that the reference frame computed using midsagittal plane first method was statistically significantly more appropriate in both subject groups regardless of the existence of orbital or auricular dystopia (27 with orbital or auricular dystopia and 27 without, both P < .05). CONCLUSIONS: The midsagittal plane first sequence improves the facial reference frames compared with the traditional axial plane first approach. However, regardless of the sequence used, clinicians need to judge the correctness of the reference frame before diagnosis or surgical planning.
Authors: J J Xia; J Gateno; J F Teichgraeber; P Yuan; K-C Chen; J Li; X Zhang; Z Tang; D M Alfi Journal: Int J Oral Maxillofac Surg Date: 2015-12 Impact factor: 2.789
Authors: J J Xia; J Gateno; J F Teichgraeber; P Yuan; J Li; K-C Chen; A Jajoo; M Nicol; D M Alfi Journal: Int J Oral Maxillofac Surg Date: 2015-12 Impact factor: 2.789