ABSTRACT
In dental field, the effect of the Magnetic Resonance Imaging (MRI) artifact generated by the magnetic metal is a significant problem. The MRI metal artifact occurs when using magnetic attachment and the keeper of the ferromagnetic substance remains implanted in the mouth as the MR image is taken. In this study, we theoretically evaluated and analyzed the artifact of MR images caused by the keeper based on the actual principle of MRI by means of simulation. As a result we were able to recognize the changes and distortion in the signal strength of the output image. We found that our results of output images and previously reported results of actual measurement are very similar. MRI artifact caused by dental magnetic metal showed that it can be reported by theoretical simulation.
Subject(s)
Artifacts , Magnetic Resonance Imaging/methods , Metals/analysis , Models, Theoretical , Evaluation Studies as Topic , Imaging, Three-Dimensional , Phantoms, Imaging , Spin LabelsABSTRACT
Toward realizing the performance of functional and versatile dental magnetic attachments in the third generation required for individual prosthesis, it is important to control retentive characteristics of the attachments. For this purpose, three new types of magnetic attachment, i.e., split-pole type with a slant magnetization, modified split-pole type, and cylinder type, have been developed and evaluated in terms of the restoring force as well as the retentive force. The new attachments are designed to have high corrosion resistance, combining magnetic and nonmagnetic stainless steels and microlaser welding similar to the usual cup-yoke and sandwich-yoke types. It has been found that the two split-pole types have stronger restoring force and the cylinder type has weaker restoring force in comparison with the usual magnetic attachments. The attachments can be used properly and selectively according to individual requirement on abutment state and denture retention. As a result, the newly developed attachments may provide flexible retention performance useful for more effective and extensive applications of a magnetic attachment.
