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A potential MRI hazard: forces on dental magnet keepers
A G Gegauff1, K A Laurell, A Thavendrarajah
1College of Dentistry, Ohio State University, Columbus 43210.
Journal of Oral Rehabilitation
|September 1, 1990
Summary
This study assessed magnetic forces on dental prosthetic keepers during MRI scans. Results show minimal risk of patient injury from displacement if keepers are securely attached.
Area of Science:
- Biomaterials Science
- Medical Physics
- Dental Prosthetics
Background:
- Dental prosthetic magnetic keepers are used for retention.
- Magnetic Resonance Imaging (MRI) utilizes strong magnetic fields.
- Potential patient injury during MRI due to magnetic forces on implants is a concern.
Purpose of the Study:
- To quantify the forces exerted on dental prosthetic magnetic keepers within MRI environments.
- To evaluate the risk of patient injury from the displacement of these keepers during MRI procedures.
Main Methods:
- Five dental prosthetic keepers (four pre-formed, one castable alloy) were tested.
- Magnetizations and high-field susceptibilities were measured using a vibrating sample magnetometer.
- Magnetic field intensity data from a 1-5 tesla MRI system was used to calculate forces.
Main Results:
- Maximum forces on pre-formed keepers ranged from 0.12-0.24 N.
- The castable alloy experienced a maximum force of 3.67 MNm-3.
- Force calculations were plotted against distance from the main magnetic coil.
Conclusions:
- The forces on dental prosthetic magnetic keepers are generally low.
- Patient injury risk from keeper displacement during MRI is minimal when properly secured.
- Proper attachment to supporting structures is crucial for patient safety during MRI.