Abstract：
OBJECTIVE: To investigate artefacts produced by different orthodontic brackets and wires in cone-beam computed tomography (CBCT) scans.
METHODS: Two dental arches were made using extracted human teeth and plaster. Three pairs of acetate plates containing different brackets - metallic, ceramic, and self-ligating ceramic with NiTi clip - along with a control plate (i.e., without brackets) were prepared. Wire changes (NiTi and steel) were made during CBCT acquisitions, performed with a fixed exposure protocol. Axial slices were selected for mean gray values and standard deviation measurement in three regions of interest (buccal, lingual, and tooth). Noise and contrast-to-noise ratio (CNR) were calculated and compared among the different brackets and wires by ANOVA with a significance level of 5%.
RESULTS: Overall, the buccal and tooth region were mostly affected by the metallic and self-ligating brackets, showing higher noise, and lower CNR (p < 0.05). On the other hand, less impact of ceramic brackets in the image quality was observed (p ≥ 0.05). The lingual region did not show expressive differences among the brackets and wire combinations (p ≥ 0.05). The presence of wire associated with the brackets did not worsen image quality (p ≥ 0.05).
CONCLUSIONS: In conclusion, metallic and self-ligating brackets have greater artefact expression than ceramic brackets. The wire did not influence image quality.
CONCLUSIONS: One should pay attention to the type of brackets when requesting a CBCT scan during treatment, as metallic and self-ligating brackets may express greater artefacts than ceramic brackets.
METHODS: Two dental arches were made using extracted human teeth and plaster. Three pairs of acetate plates containing different brackets - metallic, ceramic, and self-ligating ceramic with NiTi clip - along with a control plate (i.e., without brackets) were prepared. Wire changes (NiTi and steel) were made during CBCT acquisitions, performed with a fixed exposure protocol. Axial slices were selected for mean gray values and standard deviation measurement in three regions of interest (buccal, lingual, and tooth). Noise and contrast-to-noise ratio (CNR) were calculated and compared among the different brackets and wires by ANOVA with a significance level of 5%.
RESULTS: Overall, the buccal and tooth region were mostly affected by the metallic and self-ligating brackets, showing higher noise, and lower CNR (p < 0.05). On the other hand, less impact of ceramic brackets in the image quality was observed (p ≥ 0.05). The lingual region did not show expressive differences among the brackets and wire combinations (p ≥ 0.05). The presence of wire associated with the brackets did not worsen image quality (p ≥ 0.05).
CONCLUSIONS: In conclusion, metallic and self-ligating brackets have greater artefact expression than ceramic brackets. The wire did not influence image quality.
CONCLUSIONS: One should pay attention to the type of brackets when requesting a CBCT scan during treatment, as metallic and self-ligating brackets may express greater artefacts than ceramic brackets.
摘要：
目的：研究锥形束计算机断层扫描（CBCT）扫描中不同正畸托槽和导线产生的伪影。
方法：使用拔除的人牙和石膏制作两个牙弓。三对包含不同支架的醋酸盐板-金属，陶瓷,和带NiTi夹子的自锁陶瓷-以及控制板(即，没有括号)是准备好的。在CBCT采集期间进行了导线更换(NiTi和钢)，用固定的暴露方案进行。选择轴向切片进行三个感兴趣区域的平均灰度值和标准偏差测量（口腔，语言,和牙齿）。通过ANOVA计算并比较不同支架和导线之间的噪声和对比噪声比（CNR），显著性水平为5％。
结果：总体而言，口腔和牙齿区域主要受到金属和自锁托槽的影响，显示更高的噪音，和较低的CNR(p<0.05)。另一方面,观察到陶瓷支架对图像质量的影响较小(p≥0.05)。舌侧区域在托槽和钢丝组合之间没有表现出表达差异（p≥0.05）。与支架相关的导线的存在并未使图像质量恶化（p≥0.05）。
结论：结论：金属托槽和自锁托槽比陶瓷托槽有更大的假象表现。该线不影响图像质量。
结论：在治疗期间要求CBCT扫描时应注意支架的类型，因为金属和自锁托槽可能比陶瓷托槽表现出更大的伪影。
方法：使用拔除的人牙和石膏制作两个牙弓。三对包含不同支架的醋酸盐板-金属，陶瓷,和带NiTi夹子的自锁陶瓷-以及控制板(即，没有括号)是准备好的。在CBCT采集期间进行了导线更换(NiTi和钢)，用固定的暴露方案进行。选择轴向切片进行三个感兴趣区域的平均灰度值和标准偏差测量（口腔，语言,和牙齿）。通过ANOVA计算并比较不同支架和导线之间的噪声和对比噪声比（CNR），显著性水平为5％。
结果：总体而言，口腔和牙齿区域主要受到金属和自锁托槽的影响，显示更高的噪音，和较低的CNR(p<0.05)。另一方面,观察到陶瓷支架对图像质量的影响较小(p≥0.05)。舌侧区域在托槽和钢丝组合之间没有表现出表达差异（p≥0.05）。与支架相关的导线的存在并未使图像质量恶化（p≥0.05）。
结论：结论：金属托槽和自锁托槽比陶瓷托槽有更大的假象表现。该线不影响图像质量。
结论：在治疗期间要求CBCT扫描时应注意支架的类型，因为金属和自锁托槽可能比陶瓷托槽表现出更大的伪影。
