Study Centre for Multidisciplinary Regenerative Research, University of Rome "G. Marconi", Via Vittoria Colonna, 11, 00193, Rome, Italy.
San Rossore Dental Unit, San Rossore Private Hospital, Viale delle Cascine, 152/f, 56122, Pisa, Italy.
Oral Radiol. 2020 Jul;36(3):288-306. doi: 10.1007/s11282-019-00374-5. Epub 2019 Feb 4.
We sought to validate a new method to detect the degree of correlation between simulated and real tilted blade implants as they appear on a single two-dimensional radiograph.
The angular correction factor (CF^) was defined as the coupling of two subsequent angle transformations, a set of five angular values describing the theoretical radiographic appearance of the blade implant: (1) three consecutive rotations about the axes of the blade ([Formula: see text], θ, and ψ, standing for pitch, roll, and yaw, respectively) to represent the polarization directions; (2) a two-dimensional projection defined by two angles (λ and [Formula: see text], respectively, longitude and latitude) to represent the vector of the X-ray beam intersecting the detector plate. Data of patients who received fixed prostheses supported by blade-form implants were employed to calculate a dimensional correction factor (CF°), a specific length through the major axis. The simulation of a distorted radiograph of a blade positioned in space was compared with the real radiograph. Differences in the angular measurements served as an initial test to assess the effectiveness of the method.
In the acquired sets of periapical radiographs, mean misalignments of + 3.58° in longitude and - 0.04° in latitude were registered. The following variations were detected during the accuracy testing: the absolute error was 0.1 ± 7.5° for angle [Formula: see text]; 2.4 ± 6.7° for angle θ; - 1.0 ± 3.7° for angle ψ; 4.5 ± 8.6° for angle λ; and 2.0 ± 9.3° for angle [Formula: see text]. The linear dependence between CF° and CF^ was estimated by a robust linear regression: slope + 0.991, intercept + 0.007, and adjusted R 0.992.
This a posteriori analysis introduces the explicit trigonometric equations of the theoretical standard (CF^) used to describe the blade implant radiographic position and misalignment on two-dimensional radiographs.
我们旨在验证一种新方法，以检测在单个二维射线照片上模拟和真实倾斜叶片植入物之间相关性的程度。
角度校正因子（CF^）定义为两个连续角度变换的耦合，一组五个角度值描述了叶片植入物的理论射线照相外观：（1）围绕叶片轴的三个连续旋转（[公式：见文本]，θ和ψ，分别代表俯仰、滚动和偏航），以表示极化方向；（2）通过两个角度（λ和[公式：见文本]，分别代表射线束与探测器板相交的矢量的经度和纬度）定义的二维投影。使用接受叶片形式植入物固定修复体的患者的数据来计算尺寸校正因子（CF°），这是穿过主轴的特定长度。比较空间中定位的叶片的失真射线照片的模拟与真实射线照片。角度测量的差异作为评估该方法有效性的初步测试。
在获得的根尖射线照片集中，记录到经度的平均偏差为+3.58°，纬度的平均偏差为-0.04°。在准确性测试期间检测到以下变化：角度[公式：见文本]的绝对误差为 0.1±7.5°；角度θ的绝对误差为 2.4±6.7°；角度 ψ 的绝对误差为-1.0±3.7°；角度 λ 的绝对误差为 4.5±8.6°；角度 [公式：见文本]的绝对误差为 2.0±9.3°。通过稳健线性回归估计 CF°和 CF^之间的线性关系：斜率+0.991，截距+0.007，调整后的 R 值为 0.992。
这项事后分析介绍了用于描述二维射线照片上叶片植入物射线照相位置和错位的理论标准（CF^）的明确三角函数方程。
