From the Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Akdeniz University, P.K. 10 Dumlupinar Bulvari Kampus, 07058 Konyaalti/Antalya, Turkey (S.Y.); and Department of Oral and Maxillofacial Radiology, Faculty of Dentistry, Kirikkale University, Kirikkale, Turkey (M.Z.A.).
Radiology. 2018 Sep;288(3):799-803. doi: 10.1148/radiol.2018172597. Epub 2018 Jun 26.
Purpose To evaluate ex vivo mercury release from dental amalgam after 7.0-T and 1.5-T MRI. Materials and Methods The authors evaluated 60 caries-free molar or premolar teeth that had been extracted for clinical indications. Two-sided cavities were opened in each tooth and amalgam fillings applied. After 9 days, two groups of 20 randomly selected teeth were placed in 20 mL of artificial saliva immediately followed by 20 minutes of MRI exposure at 1.5 or 7.0 T. A control group of teeth was placed in artificial saliva without undergoing MRI exposure. The teeth were removed from the artificial saliva 24 hours later, and the saliva was analyzed for mercury content by using inductively coupled plasma mass spectrometry. One-way analysis of variance was used to compare the mean mercury values among the three independent groups, and the Tukey test was used for multiple comparisons of the mean values. Results The mean mercury content of the artificial saliva was 673 μg/L ± 179 in the 7.0-T MRI group, 172 μg/L ± 60 in the 1.5-T MRI group, and 141 μg/L ± 152 in the control group. The mercury content in the 7.0-T group was greater than that in both the 1.5-T group (P < .001; 95% confidence interval: 368 μg/L, 633 μg/L) and the control group (P < .001; 95% confidence interval: 416 μg/L, 648 μg/L). There was no statistically significant difference in mercury content between the 1.5-T and control groups (P = .84; 95% confidence interval: -164 μg/L, 110 μg/L). Conclusion In an ex vivo setting, mercury was released from amalgam fillings after exposure to 7.0-T MRI but not 1.5-T MRI.
评估 7.0-T 和 1.5-T MRI 后牙科汞合金的体外汞释放。
作者评估了 60 颗因临床原因拔除的无龋磨牙或前磨牙。在每颗牙齿上打开双侧窝洞，并应用汞合金填充物。9 天后，将随机选择的 20 颗牙齿分为两组，每组 20 颗，分别置于 20mL 人工唾液中，随后立即在 1.5 或 7.0T 下进行 20 分钟的 MRI 暴露。一组牙齿置于人工唾液中，不进行 MRI 暴露，作为对照组。24 小时后，将牙齿从人工唾液中取出，并用电感耦合等离子体质谱法分析唾液中的汞含量。采用单因素方差分析比较三组独立组间的平均汞值，采用 Tukey 检验进行均值间的多重比较。
7.0-T MRI 组人工唾液的平均汞含量为 673μg/L±179，1.5-T MRI 组为 172μg/L±60，对照组为 141μg/L±152。7.0-T 组的汞含量明显高于 1.5-T 组（P<0.001；95%置信区间：368μg/L，633μg/L）和对照组（P<0.001；95%置信区间：416μg/L，648μg/L）。1.5-T 组与对照组之间的汞含量无统计学差异（P=0.84；95%置信区间：-164μg/L，110μg/L）。
在体外环境中，汞合金填充物在暴露于 7.0-T MRI 后会释放汞，但在暴露于 1.5-T MRI 后不会释放。
