INTRODUCTION: Magnetic resonance imaging (MRI) has the potential to aid in determining the presence and extent of cracks/fractures in teeth because of better contrast without ionizing radiation. The objectives were to develop MRI criteria for root crack/fracture identification and to establish reliability and accuracy in their detection.
METHODS: MRI-based criteria for crack/fracture appearance was developed by an MRI physicist and a panel of 6 dentists. Twenty-nine human adult teeth previously extracted after a clinical diagnosis of a root crack/fracture were frequency matched to 29 controls. Samples were scanned using an in vivo MRI protocol and the reference standard (ie, ex vivo limited field of view cone-beam computed tomographic [CBCT] imaging). A blinded, 4-member panel evaluated the images with a proportion randomly retested to establish intrarater reliability. Overall observer agreement, sensitivity, and specificity were computed for each imaging modality.
RESULTS: Subjectively, MRI has increased crack/fracture contrast and is less prone to artifacts from radiodense materials relative to CBCT imaging. Intrarater reliability for MRI was fair to excellent (κ = 0.38-1.00), and for CBCT imaging, it was moderate to excellent (κ = 0.66-1.00). Sensitivity for MRI was 0.59 (95% confidence interval [CI], 0.39-0.76; P = .46), and for CBCT imaging, it was 0.59 (95% CI, 0.59-0.76; P = .46). Specificity for MRI was 0.83 (95% CI, 0.64-0.94; P < .01), and for CBCT imaging, it was 0.90 (95% CI, 0.73-0.98; P < .01).
CONCLUSIONS: Despite advantages of increased contrast and the absence of artifacts from radiodense materials in MRI, comparable measures of sensitivity and specificity (to limited field of view CBCT imaging) suggest MRI quality improvements are needed, specifically in image acquisition and postprocessing parameters. Given the early stage of technology development, there may be a use for MRI in detecting cracks/fractures in teeth.
Bibliographical noteFunding Information:
Supported by the National Institutes of Health (grant nos. P41-RR008079 , K12-RR023247 , and S10-RR023730 ), the Keck Foundation , and in part by the American Association of Endodontists Foundation .
Supported by the National Institutes of Health (grant nos. P41-RR008079, K12-RR023247, and S10-RR023730), the Keck Foundation, and in part by the American Association of Endodontists Foundation. Dr Idiyatullin is entitled to sales royalty through the University of Minnesota for products related to the research described in this article. Dr Nixdorf owns equity in and serves as CEO of MinnScan, the company that owns Intellectual Property used in this research. These relationships have been reviewed and managed by the University of Minnesota in accordance with its conflict of interest policies. Opinions and assertions contained herein are those of the authors and are not to be construed as necessarily representing the views of the respective organizations or the National Institutes of Health.
- Cone-beam computed tomography
- magnetic resonance imaging
- sweep imaging with Fourier transformation