Department of Radiology, Mayo Clinic, Rochester, Minnesota, USA.
Division of Orthodontics and Dentofacial Orthopedics, Department of Dental Specialties, Mayo Clinic, Rochester, Minnesota, USA.
Magn Reson Med. 2024 Feb;91(2):660-669. doi: 10.1002/mrm.29872. Epub 2023 Sep 27.
Dental amalgam contains mercury and is commonly used in dental restorations. The impact of MRI on mercury excretion from dental amalgam is not well understood across clinical field strengths, especially 7T. We investigated the effects of MRI exposure on mercury excretion using fresh, lab-created dental amalgam restorations and in extracted teeth with old, pre-existing restorations.
Donated, unfilled human teeth (n = 120) were restored with amalgam before being stored in saline, artificial saliva, or a dry box prior to MRI scanning. The teeth were placed in individual tubes of fresh artificial saliva and scanned at 1.5T, 3T, or 7T or left unscanned as controls. Mercury concentrations were measured 24-30 h later. Donated teeth with pre-existing restorations (n = 40) were stored in artificial saliva, scanned at 7T or left unscanned as controls, and mercury concentration tested.
For teeth extracted and restored in a laboratory, no significant difference was found (F = 2.42, P = 0.072) between mean mercury concentrations of unscanned teeth (13.72 μg/L) and teeth scanned at 1.5T (10.88 μg/L), 3T (12.65 μg/L), or 7T (8.88 μg/L). For teeth extracted with previously placed restorations, no significant difference (P = 0.288) was found between unscanned controls (4.28 μg/L) and teeth scanned at 7T (6.63 μg/L).
MRI of dental amalgam does not significantly increase mercury excretion at 1.5T, 3T, or 7T compared to unscanned teeth. This holds true for controlled laboratory restorations as well as for those placed and lived with prior to extraction and scanning, demonstrating no added risk to the clinical patient or research subject.
汞合金含有汞，常用于牙科修复。磁共振成像（MRI）对不同临床场强下，尤其是 7T 场强下汞合金中汞的排泄的影响尚未完全明确。我们使用新鲜的实验室制作的汞合金修复体以及具有旧有修复体的拔除牙齿来研究 MRI 暴露对汞排泄的影响。
在将捐赠的未填充人牙（n=120）用汞合金修复之前，将其储存在盐水中、人工唾液中或干燥箱中，然后再进行 MRI 扫描。将牙齿放入新鲜人工唾液的单独管中，并在 1.5T、3T 或 7T 下进行扫描，或作为对照不进行扫描。24-30 小时后测量汞浓度。具有旧有修复体的捐赠牙齿（n=40）储存在人工唾液中，在 7T 下扫描或作为对照不进行扫描，并测试汞浓度。
对于在实验室中拔除并修复的牙齿，未扫描牙齿（13.72μg/L）和在 1.5T（10.88μg/L）、3T（12.65μg/L）或 7T（8.88μg/L）下扫描的牙齿之间的汞浓度平均值无显著差异（F=2.42，P=0.072）。对于拔除时带有先前放置的修复体的牙齿，未扫描对照组（4.28μg/L）和在 7T 下扫描的牙齿（6.63μg/L）之间无显著差异（P=0.288）。
与未扫描牙齿相比，1.5T、3T 或 7T 的 MRI 检查不会显著增加汞合金中的汞排泄。这对于实验室控制的修复体以及在拔除和扫描之前放置和使用的修复体都是如此，这表明对临床患者或研究对象没有增加风险。
