TY - JOUR T1 - Dental bur fragments causing metal artifacts on MR images. JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 317 LP - 319 VL - 19 IS - 2 AU - T Kaneda AU - M Minami AU - H D Curtin AU - T Utsunomiya AU - I Shirouzu AU - M Yamashiro AU - H Kiba AU - H Yamamoto AU - S Ohba Y1 - 1998/02/01 UR - http://www.ajnr.org/content/19/2/317.abstract N2 - PURPOSE Our purpose was to define the role of dental bur fragments in producing metal artifacts on MR images.METHODS Dental prosthetic reconstructions were made for two dogs. The two lower second premolars were prepared for full-cast crowns by using a diamond bur. The crown margin was placed subgingivally on the right side (1 mm below the free gingival margin) and at the same level as the free gingival margin on the left side. After 1 week, full-cast crowns were cemented in place. MR imaging was performed 7 days later.RESULTS Metal artifacts appeared in both second premolar regions of the mandible on MR images, with the right side, in which the crown margin was positioned subgingivally, displaying a larger signal distortion than the left side. After removal of the crown, the artifact remained on the right. On histopathologic examination, bur fragments were detected in the gingiva, more on the right than on the left. X-ray fluorescent element analysis showed iron in the gingival tissue containing bur fragments.CONCLUSION Distortion of MR images was considered to be attributable in part to the damage of the gingiva and in part to the presence of dental bur fragments. ER -