Use of dental MRI for radiation-free guided dental implant planning: a prospective, in vivo study of accuracy and reliability

Objectives To evaluate the accuracy and reliability of dental MRI for static guided implant surgery planning. Materials and methods In this prospective study, a 0.4-mm isotropic, artifact-suppressed, 3T MRI protocol was used for implant planning and surgical guide production in participants in need of dental implants. Two dentists decided on treatment plan. Surgical guides were placed intraorally during a subsequent reference cone beam computed tomography (CBCT) scan. Inter-rater and inter-modality agreement were assessed by Cohen's kappa. For each participant, dental MRI and CBCT datasets were co-registered to determine three-dimensional and angular deviations between planned and surgically guided implant positions. Results Forty-five implants among 30 study participants were planned and evaluated (17 women, 13 men, mean age 56.9 +/- 13.1 years). Inter-rater agreement (mean kappa 0.814; range 0.704-0.927) and inter-modality agreement (mean kappa 0.879; range 0.782-0.901) were both excellent for the dental MRI-based treatment plans. Mean three-dimensional deviations were 1.1 +/- 0.7 (entry point) and 1.3 +/- 0.7 mm (apex). Mean angular deviation was 2.4 +/- 1.5 degrees. CBCT-based adjustments of MRI plans were necessary for implant position in 29.5% and for implant axis in 6.8% of all implant sites. Changes were larger in the group with shortened dental arches compared with those for tooth gaps. Except for one implant site, all guides were suitable for clinical use. Conclusion This feasibility study indicates that dental MRI is reliable and sufficiently accurate for surgical guide production. Nevertheless, more studies are needed to increase its accuracy before it can be used for implant planning outside clinical trials.