Radiofrequency heating of metallic dental devices during 3.0 T MRI

Abstract

Objectives: To estimate the risk of injury from radiofrequency (RF) heating of metallic dental devices in use during 3.0 T MRI. Methods: The whole-body specific absorption rate (WB-SAR) was calculated on the basis of saline temperature elevation under the maximum RF irradiation for 15 min to determine the operation parameters for the heating test. The temperature changes of three types of threeunit bridges, a full-arch fixed dental prosthesis and an orthodontic appliance in use during MRI with a 3.0 T MR system (Magnetom Ò Verio; Siemens AG, Erlangen, Germany) were then tested in accordance with the American Society for Testing and Materials F2182-09 standardized procedure under the maximum RF heating during 15 min RF irradiation. Results: The system console-predicted WB-SAR was approximately 1.4 W kg 21 and that measured with a saline phantom was 2.1 W kg 21. In the assessment of RF heating, the highest temperature increase was 11.80°C in the bridges, 11.59°C in the full-arch fixed dental prosthesis and 12.61°C in the orthodontic appliance. Conclusions: The relatively minor RF heating of dental casting material-based prostheses in Magnetom Verio systems in the normal operating mode should not pose a risk to patients. However, orthodontic appliances may exhibit RF heating above the industrial standard (CENELEC standard prEN45502-2-3); therefore, the wire should be removed from the bracket or a spacer should be used between the appliance and the oral mucosa during MRI.

Influence of Metal Artifact by Orthodontic Appliances on Brain MRI

“…0 T. Most previous ex vivo tests performed to assess objects for MR safety used units with a static magnetic field of 1.5 T or lower (6). MRI at 3 Tesla or higher has become common in daily practice (7)(8)(9), and some clinical MRI operate at up to 9.4T (10).…”

Evaluation of magnetic resonance imaging issues of titanium and stainless steel brackets

“…In our trial, no bracket temperature increase exceeding 0.1°C has been found, which corresponds with other studies 30,31 . Contrarily, Görgülü et al 29 reported a stainless steel bracket set heating up to 3.04°, while Hasegawa et al 41 noted a temperature rise of 2.61°. Such heterogeneity was probably caused by different exposition time, significant variation of tested appliance design and dissimilar heat transfer conditions.…”

Effect of orthodontic brackets and different wires on radiofrequency heating and magnetic field interactions during 3-T MRI

“…In the previous studies, which aimed to measure RF heating during MRI, artificial teeth were used 18 or the orthodontic appliances were inserted directly into gelled phantom models. 19,20 In the present study, to simulate actual clinical conditions, 40 human teeth were used for the application of brackets and wires.…”