Follow-up of periapical inflammation after root canal retreatment and surgical endodontic treatment using dental-dedicated magnetic resonance imaging: a case report

The aim is to present a dental-dedicated magnetic resonance imaging (ddMRI)-based diagnosis and follow-up in a clinical case of apical periodontitis (AP) on a root canal treated (RCT) tooth. Persistent AP in RCT teeth can be difficult to distinguish from scar tissue or incomplete healing. In the absence of symptoms, no currently known imaging method can verify the presence of inflammation. ddMRI is a novel imaging modality proposed for dentistry, that has the potential to reveal inflammation. A 50-year-old male presented with mild symptoms from a previously RCT 36. ddMRI suggested mild inflammation, and an intraoral image revealed a periapical radiolucency. The tooth was non-surgically endodontically retreated. During follow-up, no exacerbation of the inflammation was detected on ddMRI. However, one year after retreatment, a periapical radiolucency persisted, and the ddMRI indicated that the inflammation had not resolved. Surgical endodontic retreatment was performed, and a tissue sample was retrieved from the periapical area. A histopathological analysis revealed inflammation as suspected from the hyperintense signal seen on ddMRI. Despite treatment, the inflammation did not resolve, and after development of a fistula, the tooth was extracted.