Objectives: To establish the source of metallic artifacts on postoperative MRI of the temporomandibular joint after arthroplasty.
Methods: An experiment was carried out to evaluate MR artifacts which were thought to have been caused by minute metallic particles deposited at surgery. Four types of cutting instruments were used to cut an extracted tooth: a diamond bur attached to a dental air turbine handpiece, a steel bur and bone bur attached to a dental micromotor handpiece and a bone file. The tooth fragments were collected in plastic centrifuge tubes in water. These samples were evaluated with six MR sequences.
Results: MR artifacts were clearly demonstrated in samples using the bone bur and the bone file but not the diamond and steel burs.
Conclusions: The artifacts seen on postoperative MRI were derived from minute metal particles from the bone bur or file used for condylar arthroplasty. Metal artifacts should be considered when interpreting postoperative MR images.