No Increased Mercury Release from Dental Restorations at 1.5T, 3T, or 7T MRI

Purpose: Dental amalgam contains mercury and is commonly used in dental restorations. The impact of MRI on mercury excretion from dental amalgam is notwell understood across clinical field strengths, especially 7T. We investigated the effects ofMRI exposure onmercury excretion using fresh, lab-created dental amalgam restorations and in extracted teeth with old, pre- existing restorations. Methods: 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. Results: 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 mu g/L) and teeth scanned at 1.5T (10.88 mu g/L), 3T (12.65 mu g/L), or 7T (8.88 mu g/L). For teeth extracted with previously placed restorations, no significant difference (P = 0.288) was found between unscanned controls (4.28 mu g/L) and teeth scanned at 7T (6.63 mu g/L). Conclusion: 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.

Automated summary

The study found that MRI does not significantly increase mercury excretion from dental amalgam at 1.5T, 3T, or 7T field strengths, both for laboratory restorations and for those placed and lived with prior to extraction and scanning, demonstrating no added risk to the clinical patient or research subject.