Comparison of dental-dedicated MRI to 2D radiographic images and cone beam CT in the assessment of lower third molars: a prospective study

OBJECTIVES: The aim of this study is to show that the use of 0.55 T MRI combined with a "dental-dedicated" coil produces images of sufficient diagnostic value to assess lower third molars (LTMs), that are not inferior to currently utilized dental-oriented radiographic images. METHODS: Dental-dedicated MRI (ddMRI) scans were acquired using a Magnetom Free.Max 0.55 T scanner combined with a dedicated dental coil. Three observers assessed all images according to predefined criteria. Twenty percent of images were assessed twice by all observers. Kappa statistics were performed to assess intra- and inter-observer agreement as well as inter-modality agreement. RESULTS: Dental-dedicated MRI was acquired on 67 patients (89 LTMs) in addition to initial radiographic exams (intraoral, panoramic, and/or CBCT). Inter-observer agreement for each modality ranged from low to perfect (intraoral/panoramic 0.480-0.942 [average 0.74], CBCT 0.218-1.000 [average 0.69], ddMRI -0.038 to 0.889 [average 0.53]). Intra-observer agreement ranged from low to perfect (intraoral/panoramic -0.047 to 1.000 [average 0.76], CBCT 0.389-1.000 [average 0.83], ddMRI -0.025 to 1.000 [average 0.61]). Inter-modality agreement ranged from low to high (intraoral/panoramic vs CBCT -0.078 to 0.743 [average 0.32], intraoral/panoramic vs ddMRI -0.078 to 0.752 [average 0.30], CBCT vs ddMRI 0.074-0.886 [average 0.49]). CONCLUSION: Dental-dedicated MRI could be a feasible diagnostic modality for LTM imaging. The modality shows promise for radiation-free imaging in the future. ADVANCES IN KNOWLEDGE: This article is the first to demonstrate the use of ddMRI in LTM imaging and to compare the modality to existing modalities. The added value of this radiation-free modality can be beneficial to dentists and patients in the future.