口腔修复材料在锥形束CT影像中伪影的定量评价

Quantitative assessment on artifacts of dental restorative materials in cone beam computed tomography

目的：定量评价氧化锆等8种常见口腔修复材料在锥形束CT影像中产生伪影的程度。方法： 针对下颌第一磨牙全冠预备体，分别制作氧化锆、玻璃陶瓷、聚合瓷、金铂合金、纯钛、金钯合金、钴铬合金和镍铬合金共8种全冠，用离体牙作对照，固定在光固化树脂固定板上。用锥形束CT扫描全冠及离体牙，将DICOM数据导入MIMICS10.0软件，在二维断层图像中，定量评价全冠周围伪影的条纹数量和最大径。结果： 在二维断层图像中，天然牙、玻璃陶瓷和聚合瓷无伪影，氧化锆和金属均产生条状伪影，条数为5~9条/全冠，左右和上下最大径分别为2.4~2.6 cm和2.2~2.7 cm。结论： 在锥形束CT二维断层图像中，氧化锆和金属全冠周围均会产生伪影，玻璃陶瓷、聚合瓷全冠和天然牙齿不产生伪影。

To quantitatively evaluate the artifacts appearance of eight kinds of common dental restorative materials, such as zirconia. Methods： For the full-crown tooth preparation of mandibular first molar, eight kinds of full-crowns, such as zirconia all-ceramic crown, glass ceramic crown, ceramage crown, Au-Pt based porcelain-fused-metal （PFM） crown, Pure Titanium PFM crown, Co-Cr PFM crown, Ni-Cr PFM crown, and Au-Pd metal crown were fabricated. And natural teeth in vitro were used as controls. These full-crown and natural teeth in vitro were mounted an ultraviolet-curable resin fixed plate. High resolution cone beam computed tomography （CBCT） was used to scan all of the crowns and natural teeth in vitro, and their DICOM data were imported into software MIMICS 10.0. Then, the number of stripes and the maximum diameters of artifacts around the full-crowns were evaluated quantitatively in two-dimensional tomography images. Results： In the two-dimensional tomography images,the artifacts did not appear around the natural teeth in vitro, glass ceramic crown, and ceramage crown. But thr artifacts appeared around the zirconia all-ceramic and metal crown. The number of stripes of artifacts was five to nine per one crown. The maximum diameters of the artifacts were 2.4 to 2.6 cm and 2.2 to 2.7 cm. Conclusion： In the two-dimensional tomography images of CBCT, stripe-like and radical artifacts were caused around the zirconia all-ceramic crown and metal based porcelain-fused-metal crowns. These artifacts could lower the imaging quality of the full crown shape greatly. The artifact was not caused around the natural teeth in vitro, glass ceramic crown, and ceramage crown.