Department of Dentistry, State University of Paraíba, Campina Grande, PB, Brazil.
Department of Clinical and Social Dentistry, Federal University of Paraíba, João Pessoa, Brazil.
Int Endod J. 2019 Feb;52(2):223-236. doi: 10.1111/iej.12999. Epub 2018 Sep 14.
To evaluate artefact intensity in cone beam computed tomography (CBCT) images of two alloys used in metal posts scanned using different exposure parameters.
The sample consisted of 20 single-rooted teeth divided into two groups for use with either a NiCr post or AgPd post. All teeth were scanned with and without their corresponding metal posts and with and without the presence of an extra restored tooth in the arch. The samples were scanned using CS 9000 3D scanner with two exposure protocols: 85 kV 6.3 mA and 85 kV 10 mA. Voxel size and FOV were fixed at 0.100 mm and 5 cm × 3.75 cm. The presence of artefacts was assessed qualitatively by two calibrated observers using the CBCT volume and paired 2D images, and quantitatively by one trained observer, using ImageJ software. Wilcoxon's signed rank, Mann-Whitney, kappa and chi-square tests were used for qualitative analyses. Two-way anova and Tukey's tests were used for quantitative analyses. All analyses were conducted considering the 95% confidence level (α < 0.05).
For the CBCT volume qualitative analysis, significant differences were observed between the metal alloys in the presence of an extra restored tooth, with higher artefact intensity for AgPd when assessing hypodense halos and lines (P = 0.006). Images with two restored teeth had significantly more hypodense and hyperdense lines (P = 0.033). When evaluating exposure parameters and number of restored teeth, the paired image quality analysis revealed significant disagreement between observers for diagnostic image quality (P = 0.001). Quantitative artefact analysis revealed higher artefact intensity for the AgPd posts in the presence of two restored teeth.
Although the exposure parameters tested did not interfere with artefact intensity, post alloys with a higher atomic number and the presence of another metal structure in the arch increased artefact intensity and impaired the diagnostic quality of CBCT images.
评估两种用于金属桩的合金在使用不同曝光参数的锥形束计算机断层扫描（CBCT）图像中的伪影强度。
样本由 20 颗单根牙齿组成，分为使用 NiCr 桩或 AgPd 桩的两组。所有牙齿均在无金属桩和有金属桩的情况下进行扫描，并且在弓中有额外修复牙齿的情况下进行扫描。样本使用 CS 9000 3D 扫描仪进行扫描，使用两种曝光方案：85kV 6.3mA 和 85kV 10mA。体素大小和 FOV 固定在 0.100mm 和 5cm×3.75cm。两名经过校准的观察者使用 CBCT 体积和配对的 2D 图像对伪影的存在进行定性评估，并使用 ImageJ 软件由一名受过训练的观察者进行定量评估。Wilcoxon 符号秩检验、Mann-Whitney 检验、kappa 检验和卡方检验用于定性分析。两因素方差分析和 Tukey 检验用于定量分析。所有分析均在 95%置信水平（α<0.05）下进行。
对于 CBCT 体积的定性分析，在存在额外修复牙齿的情况下，两种金属合金之间观察到显著差异，在评估低密度晕环和线时，AgPd 的伪影强度更高（P=0.006）。有两颗修复牙齿的图像有明显更多的低密度和高密度线（P=0.033）。在评估曝光参数和修复牙齿数量时，配对图像质量分析显示观察者对诊断图像质量的评估存在显著分歧（P=0.001）。定量伪影分析显示，在存在两颗修复牙齿的情况下，AgPd 桩的伪影强度更高。
尽管测试的曝光参数并未干扰伪影强度，但原子序数较高的合金和弓中存在另一种金属结构会增加伪影强度，并降低 CBCT 图像的诊断质量。
