Abstract:

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.

Key words: crown, magnetic resonance, artifact, in vivo study