Mri Detection Of Vertical Root Fractures In Endodontically Treated Teeth

Abstract

INTRODUCTION: Vertical root fracture (VRF) is known to occur in root canal treated (RCT) teeth and results in tooth loss. VRFs are difficult to diagnose. Magnetic Resonance Imaging (MRI) has the potential to identify VRF due to beneficial partial volume averaging, without using ionizing radiation. This investigation aims to compare the sensitivity and specificity of MRI versus cone-beam computed tomography (CBCT) in detecting VRF, using micro-computed tomography (microCT) as the reference standard. It also will describe the limits of MRI for detecting VRF. METHODS: 115 extracted human tooth roots were RCT using common techniques. VRFs were induced in a proportion that resulted in 62 VRF samples and 53 non-fractured control samples. All samples were imaged in a phantom using MRI and CBCT. Axial images for MRI and CBCT were presented to three board-certified endodontists. Evaluators determined VRF status and a confidence assessment for that decision. 30% of images were resampled to calculate intra- and inter-rater reliability. For MRI, the most coronal slice with discernible VRF was measured on correlated microCT to determine the minimum VRF width (µm). RESULTS: Sensitivity for MRI and CBCT were 0.66 (95%CI:0.53-0.78) and 0.58 (95%CI:0.45-0.70). Specificity was 0.72 (95%CI:0.58-0.83) and 0.87 (95%CI:0.75-0.95). Intra-rater reliability ranged from k=0.29-0.48 for MRI and k=0.30-0.44 for CBCT. Inter-rater reliability for MRI was k=0.37 and CBCT k=0.49. Median VRF width detected using MRI was 39µm (first quartile:20µm, third quartile: 58µm). CONCLUSION: MRI demonstrated ability to repeatedly detect VRF as small as 20 µm. There was no significant difference between sensitivity nor specificity for MRI versus CBCT in detecting VRF, despite the early stage of MRI development.