Zizelmann Christoph, Hammer Beat, Gellrich Nils-Claudius, Schwestka-Polly Rainer, Rana Majeed, Bucher Peter
Department of Oral and Maxillofacial Surgery, Hannover Medical University, Hannover, Germany.
J Oral Maxillofac Surg. 2012 Aug;70(8):1944-50. doi: 10.1016/j.joms.2011.08.025. Epub 2011 Nov 12.
The purpose of this study was to evaluate the error magnitude in the clinical application of face-bow devices. Technical and methodologic inaccuracies, as well as deviations from reference planes, were determined.
The presented method is part of a 3-dimensional virtual planning procedure for orthognathic surgery and included 15 patients with dentoskeletal deformities. Cone beam computed tomography datasets obtained from patients with a referenced face-bow plane and a centric registration splint were matched with cone beam computed tomography datasets of the registered plaster model of the maxilla mounted in an articulator. To assess potential sources of methodologic errors, angulations were measured between the virtual face-bow plane and the horizontal cross bar of the virtual articulator. To evaluate the reproducibility of the anatomic reference plane, angulations between the Frankfort plane and the horizontal cross bar of the articulator were measured. Statistical significance was set at P < .05 and tested by univariate analysis of variance.
Technical and methodologic errors showed a mean deviation of 3.5°, with a median of 3.6° and SD of 2.7°. The values did not reach statistical significance (P = .1). However, there was a significant error (P < .05) in determining the position of the anatomic reference plane by face-bow transfer. The mean deviation was 7.7° (values ranged between 1.2° and 18.9°), with a median of 6.7° and SD of 5.3°.
In this study the traditional use of face-bow devices showed inaccuracies in model mounting as well as in assignment of anatomic reference planes. Three-dimensional virtual computer-assisted planning seems to be more accurate than conventional methods.
本研究旨在评估面弓装置在临床应用中的误差大小。确定技术和方法上的不准确之处，以及与参考平面的偏差。
所提出的方法是正颌外科三维虚拟规划程序的一部分，纳入了15例牙颌面畸形患者。从具有参考面弓平面和正中记录夹板的患者获取的锥形束计算机断层扫描数据集，与安装在咬合架上的上颌石膏模型的注册锥形束计算机断层扫描数据集进行匹配。为了评估方法误差的潜在来源，测量虚拟面弓平面与虚拟咬合架水平横杆之间的角度。为了评估解剖参考平面的可重复性，测量法兰克福平面与咬合架水平横杆之间的角度。统计学显著性设定为P < 0.05，并通过单因素方差分析进行检验。
技术和方法误差的平均偏差为3.5°，中位数为3.6°，标准差为2.7°。这些值未达到统计学显著性（P = 0.1）。然而，通过面弓转移确定解剖参考平面的位置存在显著误差（P < 0.05）。平均偏差为7.7°（值范围在1.2°至18.9°之间），中位数为6.7°，标准差为5.3°。
在本研究中，传统的面弓装置在模型安装以及解剖参考平面的确定方面显示出不准确。三维虚拟计算机辅助规划似乎比传统方法更准确。
