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Introduction: Cone-beam computed tomography (CBCT) is the standard imaging technique for three-dimensional evaluation of bone anatomy, but it exposes patients to ionizing radiation and lacks soft tissue contrast. Magnetic resonance imaging (MRI) offers a non-ionizing alternative capable of visualizing hard and soft tissues. This study evaluated the effect of low-resolution (LR) and high-resolution (HR) MRI on diagnostic accuracy and image quality for digital dental implant planning in the edentulous mandible, compared with CBCT.
Method: Three edentulous mandibular phantoms were scanned using CBCT, LR-MRI, and HR-MRI protocols. Two calibrated examiners digitally planned four implants per sample (n = 8 per modality). Diagnostic accuracy was assessed using angular deviation (long axis implant vs. occlusal prosthetic plane) and linear bone measurements (ridge height, ridge width, ridge-to-mandibular canal distance). Reliability was assessed using the intraclass correlation coefficient (ICC). Differences among imaging modalities were evaluated using the Friedman and Wilcoxon tests. Image quality was rated using a 5-point scale (≤2 clinically invalid; ≥3 clinically valid), with agreement assessed by percentage agreement and differences analyzed via chi-square test.
Results: A total of 96 implants were digitally planned (32 per modality). For angular deviation, anterior ICC values ranged from moderate for HR (0.584) to very good for LR (0.866) and CBCT (0.948), while posterior ICC decreased to reasonable for CBCT (0.295) and poor for both MRI protocols (LR = –0.154; HR = –0.304). No significant differences were found between imaging modalities (anterior p > 0.197; posterior p > 0.417). Linear bone measurement reliability was very good (ICC>0.827), except for ridge width in the posterior region with LR (0.780) and ridge–canal distance with HR (0.783), with no significant differences among modalities (p > 0.305). CBCT showed >85% agreement for image quality, versus 50-100% for LR and 50-75% for HR, with no significant differences (p > 0.132).
Conclusion: MRI resolution did not influence diagnostic accuracy or image quality for digital implant planning in edentulous mandibles when compared with CBCT. However, interexaminer disagreement was observed in image quality assessment. Clinical studies with larger samples are required to validate these findings.