Assessment of the root filling volume in C-shaped root canal on cone-beam CT and micro-CT in relation to nano-CT

Aim To assess the observed volume of filled C-shaped root canals from different CBCT and micro-CT having nano-CT as a reference. Materials and methods Twelve extracted mandibular molars with C-shaped root canals were endodontically treated using Reciproc Blue R25 (VDW GMBH, Munich, Germany) in a reciprocating system and filled with gutta-percha (Dentsply Maillefer) and AH Plus sealer (Dentsply DeTrey, Konstanz, Germany). CBCT scans were performed using 3 units—3D Accuitomo 170 (J. Morita, Kyoto, Japan), ProMax 3D Max (Planmeca, Helsinki, Finland), and NewTom VGi EVO (Cefla QR, Verona, Italy)—at two resolution modes: standard and high. Micro-CT and nano-CT scans were also obtained. The volume of all filled C-shaped root canals was obtained using CTAn software (Bruker, Kontich, Belgium), and the blooming artifact, in relation to nano-CT volume, was calculated. The data were evaluated by the Bland–Altman plots and ANOVA two-way for repeated measures (α = 0.05). Results All CBCT units and micro-CT showed significantly larger observed volume of root canal filling when compared to nano-CT. The blooming artifact of root canal filling in standard resolution was significantly larger than that in high resolution ( p < 0.05) in all CBCT units. Conclusions Endodontic filling material with AH Plus sealer causes blooming artifacts in CBCT units and micro-CT. Clinical relevance Considering the anatomical complexity of C-shaped root canals and the challenges associated with endodontic treatment, CBCT is frequently recommended for follow-up evaluations. However, the presence of endodontic filling material can result in blooming artifacts that may potentially impact the accurate diagnosis of endodontic complications.