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Aim: To compare measurements on images obtained by magnetic resonance imaging (MRI) and cone beam CT (CBCT) for height, width, and area in alveolar bone sites in human jaw specimens. Material and Methods: Forty edentulous alveolar posterior sites in human cadaver specimens were imaged using CBCT scanners, and with zero‐echo‐time MRI (ZTE‐MRI). Semi‐automatic volume registration was performed to generate representative coronal sections of the sites related to implant planning. ZTE‐MRI sections were also presented after grayscale inversion (INV MRI). Three observers measured bone height, bone width 5 mm from the alveolar crest, and bone area stretching from the width measurement to the top of the alveolar crest in the images. Interobserver agreement was assessed by intra‐class correlation coefficients (ICC). The measurements were analyzed using two‐way repeated measures ANOVA factoring observer and image type. Results: ICC was >0.95 for bone height, width, and bone area. No significant differences among observers (p = 0.14) or image type (p = 0.60) were found for bone height. For bone width, observer (p = 0.14) was not a significant factor, while ZTE‐MRI produced width estimates that were significantly different and systematically smaller than CBCT‐based estimates (p ≤ 0.001). Observer (p = 0.06) was not a significant factor regarding the bone area measurements, contrary to the imaging type where ZTE‐MRI led to significantly smaller area estimates than CBCT (p ≤ 0.001). Conclusion: Bone height measurements were essentially equivalent using CBCT and MRI. This was found regardless of grayscale choice for the MRI. However, ZTE‐MRI resulted in smaller estimates of bone width and area. [ABSTRACT FROM AUTHOR]

To undertake a systematic literature review of magnetic resonance imaging (MRI) employed in the three phases of implant-based oral rehabilitation: planning, execution, and follow-up. Materials and Methods: MEDLINE (PubMed) and EMBASE bibliographic databases were searched up to January 2020 for studies assessing the use of MRI alone or in connection with CT and/or CBCT in the planning, execution, or follow-up of dental implant placement and/or bone grafting procedures in the maxilla or the mandible. Included studies were also assessed according to the diagnostic imaging efficacy scale presented by Fryback and Thornbury (F&T). Results: The search strategy yielded 10 studies, which were included in the systematic review. Six studies focused on the implant planning phase, one on the immediate followup phase, and three on both planning and follow-up. No studies acquired signal from the bone. There was no consensus on the gold standard, MRI sequence, or field strength (T). One study reached F&T level 1, eight reached level 2, and one reached level 3. Conclusion: The possible transition from radiography to ionizing-radiation–free imaging through MRI is still a novelty in dentistry and has yet to establish itself as a viable imaging modality suitable for replacing CT and CBCT. More studies are needed on the accuracy of the diverse MRI possibilities when applied for implant planning, execution, and follow-up before this diagnostic method can be considered as a reality for the clinician. [ABSTRACT FROM AUTHOR]

To compare alveolar bone height and width measurements from zero-echo-time MRI (ZTE-MRI) and cone beam CT (CBCT), in human specimens. Twenty posterior edentulous sites in human cadaver specimens were imaged with CBCT and ZTE-MRI. Bone height and width at 1, 3, 5, 7 and 9 mm from the top of the alveolar ridge was measured by two trained observers in cross-sections of a site where an implant was to be planned. Twenty percent of the sample was measured in duplicate to assess method error and intra-observer reproducibility (ICC). The differences between CBCT and ZTE-MRI measurements were compared (t-test). Inter- and intra-observer reproducibility was >0.90. The method error (average between observers) for bone height was 0.45 mm and 0.39 mm, and for bone width (average) was 0.52 mm and 0.80 mm (CBCT and ZTE-MRI, respectively). The majority of the bone measurement differences were statistically insignificant, except bone width measurements at 5 mm (p ≤.05 for both observers). Mean measurement differences were not larger than the method error. ZTE-MRI is not significantly different from CBCT when comparing measurements of alveolar bone height and width. [ABSTRACT FROM AUTHOR]