两种金属烤瓷冠引起MRI伪影的研究

The study of the MRI artifacts caused by two alloys of porcelain-fused-to-metal crown

目的观察两种金属引起MRI伪影的程度。方法实验选择两种金属烤瓷冠,即■镍铬合金烤瓷冠及■金合金烤瓷冠,并以■烤瓷冠蜡型作为对照组,每组各3个样本,在1.5Tesla磁共振成像仪(GE Signa Twinspeed)上进行,对MRI伪影进行测量和分析。结果两种金属烤瓷冠所引起MRI伪影的大小之间存在统计学差异(P<0.01)。镍铬合金烤瓷冠所产生的MRI伪影明显大于金合金烤瓷冠所产生的MRI伪影。对照组不产生伪影。结论 86.2%的金合金烤瓷冠仅产生少量伪影,基本不会影响MRI检查时对周围解剖结构的观察。

Objective To observe the extension of MRI artifacts caused by two alloys of porcelain-fused-to-metal crowns. Methods We divided samples into two groups. One group consisted of 61 Ni-Cr alloy crowns and the other concisted of gold alloy crowns. The wax pattern of crowns was the control group. Each group had three samples. The samples were placed in the center of the water phantom subjected by 1.5 Tesla magnetic resonance devices. The maximum diameters of artifact are measured and analyzed. Results The results indicated significant difference among different dental materials （P〈0.01）. The artifacts caused by Ni-Cr alloy porcelain-fused-to-metal crowns and bridges are bigger than those of the gold alloy. The control group did not produce artifacts. Conclusions The gold alloy porcelain -fused-to-metal crowns produced only a small amount of artifacts, which did not affect the observation of MRI examination.