Abstract：
BACKGROUND: Accurate bracket positioning remains challenging. To avoid angulation errors, some recommend examining the panoramic radiograph during bonding. However, it can cause distortions. Cone-beam computed tomography (CBCT) provides a more precise panoramic reconstruction but with higher radiation doses. The main objective of this study is to compare the accuracy of axial positioning between direct bonding without radiography, with conventional panoramic radiograph, and with panoramic reconstruction from CBCT. The secondary objectives are to evaluate positioning accuracy of each tooth and to assess the influence of practitioner level of experience.
METHODS: Thirty practitioners, divided into two groups based on their experience performed direct bonding on a model thrice: without radiography, then with the conventional panoramic radiograph, then with the panoramic reconstruction from CBCT. Models were scanned, and angulation errors were measured using OrthoAnalyzer. Values were compared using the Friedman\'s test followed by the Bonferroni correction for multiple comparisons (P-value = 0.05).
RESULTS: For the low level of experience group, angulation errors were significantly greater than the accepted limit without radiographic reference, and significantly lower with CBCT reconstruction. For the high level of experience group, angulation errors were significantly lower than the accepted limit for the three bonding methods. For every tooth, using the panoramic reconstruction from CBCT as a reference, was the most accurate method, regardless of the level of experience. More experienced practitioners made fewer errors for the three methods.
CONCLUSIONS: Panoramic reconstruction from CBCT is the most accurate method to limit angulation errors during direct bonding. Conventional panoramic radiography remains a reliable tool if used with caution. Bonding without any radiographic reference should be avoided especially for less experienced practitioners.
METHODS: Thirty practitioners, divided into two groups based on their experience performed direct bonding on a model thrice: without radiography, then with the conventional panoramic radiograph, then with the panoramic reconstruction from CBCT. Models were scanned, and angulation errors were measured using OrthoAnalyzer. Values were compared using the Friedman\'s test followed by the Bonferroni correction for multiple comparisons (P-value = 0.05).
RESULTS: For the low level of experience group, angulation errors were significantly greater than the accepted limit without radiographic reference, and significantly lower with CBCT reconstruction. For the high level of experience group, angulation errors were significantly lower than the accepted limit for the three bonding methods. For every tooth, using the panoramic reconstruction from CBCT as a reference, was the most accurate method, regardless of the level of experience. More experienced practitioners made fewer errors for the three methods.
CONCLUSIONS: Panoramic reconstruction from CBCT is the most accurate method to limit angulation errors during direct bonding. Conventional panoramic radiography remains a reliable tool if used with caution. Bonding without any radiographic reference should be avoided especially for less experienced practitioners.
摘要：
背景：准确的支架定位仍然具有挑战性。为避免角度误差,有些人建议在粘合期间检查全景射线照片。然而,它会导致扭曲。锥形束计算机断层扫描（CBCT）提供了更精确的全景重建，但辐射剂量更高。这项研究的主要目的是比较没有射线照相术的直接结合之间的轴向定位精度，用传统的全景射线照片，并从CBCT进行全景重建。次要目标是评估每颗牙齿的定位精度并评估从业者经验水平的影响。
方法：30名从业者，根据他们的经验分为两组，三次在模型上进行直接结合：没有射线照相术，然后用传统的全景射线照片，然后用CBCT进行全景重建。模型被扫描，使用OrthoAnalyzer测量角度误差。使用Friedman检验和Bonferroni校正进行多重比较（P值=0.05）。
结果：对于低经验组，角度误差显著大于没有射线照相参考的公认极限，与CBCT重建显著降低。对于高水平的经验组，成角误差明显低于三种粘接方法的公认极限。对于每一颗牙齿，使用CBCT的全景重建作为参考，是最准确的方法，无论经验水平如何。更有经验的从业者对这三种方法的错误较少。
结论：CBCT的全景重建是限制直接结合过程中角度误差的最准确方法。如果谨慎使用，传统的全景射线照相术仍然是可靠的工具。特别是对于经验不足的从业者，应避免没有任何射线照相参考的粘合。
方法：30名从业者，根据他们的经验分为两组，三次在模型上进行直接结合：没有射线照相术，然后用传统的全景射线照片，然后用CBCT进行全景重建。模型被扫描，使用OrthoAnalyzer测量角度误差。使用Friedman检验和Bonferroni校正进行多重比较（P值=0.05）。
结果：对于低经验组，角度误差显著大于没有射线照相参考的公认极限，与CBCT重建显著降低。对于高水平的经验组，成角误差明显低于三种粘接方法的公认极限。对于每一颗牙齿，使用CBCT的全景重建作为参考，是最准确的方法，无论经验水平如何。更有经验的从业者对这三种方法的错误较少。
结论：CBCT的全景重建是限制直接结合过程中角度误差的最准确方法。如果谨慎使用，传统的全景射线照相术仍然是可靠的工具。特别是对于经验不足的从业者，应避免没有任何射线照相参考的粘合。
