目的 对口腔环境中金合金烤瓷冠与镍铬合金烤瓷冠引起的磁共振伪影进行对比研究。方法 将6个样本分镍铬合金烤瓷冠桥组和86.2%金合金烤瓷冠桥组（n=3），分别置于受试者（口腔内无缺牙和修复体）的口腔内实施磁共振扫描，观察磁共振图像，判别伪影的类型、程度和范围，计算伪影面积的像素值。采用SAS 8.2软件进行统计学分析。结果 镍铬合金磁共振伪影面积累积4层至6层图像，金合金磁共振伪影面积累积3层图像。统计学分析结果显示，与86.2%金合金烤瓷冠桥组比较，镍铬合金烤瓷冠桥组的6-烤瓷单冠产生的磁共振矢状位图像的伪影面积较大，差异有统计学意义（P<0.05），且该组引起的磁共振伪影累积层数较多（P<0.05）。结论 金合金烤瓷冠桥与镍铬合金烤瓷冠桥均会产生磁共振伪影，金合金烤瓷冠桥所产生的磁共振伪影面积较小且累积层数较少。

Objective To compare the magnetic resonance imaging (MRI) artifacts caused by porcelain-fused-to-metal crowns made of Ni-Cr alloy and Au alloy in oral cavity. Methods Six samples were divided into Ni-Cr porcelain-fused-to-metal crowns group and 86.2% Au alloy porcelain-fused-to-metal crowns group (n=3), and were placed into the oral cavity of subjects (with no prosthetics or absence of teeth) for MRI examinations. The images were observed, the types, degree and sizes of artifacts were determined, and the pixel values of area of artifacts were calculated. SAS 8.2 software was employed for statistical analysis. Results The artifacts of Ni-Cr crowns involved images of 4 to 6 layers, those of Au alloy crowns involved images of 3 layers. Statistical analysis indicated that compared with 86.2% Au alloy porcelain-fused-to-metal crowns group, the area of artifacts of sagittal images on MIR from 6-crown was significantly larger (P<0.05), and the number of layers on involved images was much bigger in Ni-Cr porcelain-fused-to-metal crowns group (P<0.05). Conclusion Both Ni-Cr porcelain-fused-to-metal crowns and Au porcelain-fused-to-metal crowns would produce artifacts in oral cavity, and the artifacts caused by Au alloy crowns are smaller in area and number of layers involved.