Diagnostic accuracy of cone beam computed tomography in the detection of furcation perforations: an in vitro comparison with periapical radiography and micro-computed tomography

Abstract

The furcation area is an anatomically complex region where the roots of multirooted teeth diverge. Visualizing pathologies and iatrogenic errors in this region is particularly challenging with conventional radiographic techniques due to factors such as superposition, root morphology, and surrounding anatomical structures. This study aimed to evaluate the detectability of artificially created furcation perforations in maxillary and mandibular molars, to compare the diagnostic accuracy of different imaging modalities, and to assess the reliability of CBCT linear measurements using micro-computed tomography (micro-CT) as the gold standard reference method. This in vitro study included 56 maxillary and mandibular molar teeth with artificially created furcation perforations, evaluated in two stages: before and after root canal treatment. Cone beam computed tomography (CBCT) images were acquired using a NewTom 7G device at Ankara University Faculty of Dentistry, with three scan modes (Low Dose, Regular, and Best Quality) and six voxel sizes (0.09, 0.12, 0.15, 0.18, 0.24, and 0.30 mm). Digital periapical radiographs obtained with the paralleling technique were also included. Three observers with different specialties and experience levels evaluated the images using five diagnostic categories. Intraobserver and interobserver agreement were analyzed using the kappa coefficient. To objectively validate the accuracy of CBCT linear measurements, perforation dimensions obtained from sagittal CBCT sections were compared against micro-CT measurements — which served as the gold standard due to its superior spatial resolution and three-dimensional precision — using the intraclass correlation coefficient (ICC). CBCT, particularly at lower voxel sizes providing higher resolution, offered significantly greater diagnostic accuracy than periapical radiography in the detection of furcation perforations. The presence of root canal filling material reduced detectability in some scan mode and voxel size combinations. CBCT linear measurements demonstrated a high level of agreement with micro-CT gold standard measurements (ICC, p < 0.05), confirming the metrological reliability of CBCT in quantifying perforation dimensions. The highest diagnostic accuracy and observer agreement were achieved using the Best Quality scan mode. Under the conditions of this in vitro study, CBCT provides a significant diagnostic advantage over periapical radiography in detecting furcation perforations. The high agreement between CBCT measurements and micro-CT – being accepted as the gold standard- supports the reliability of CBCT for dimensional assessment of furcation perforations. High-resolution modes with small voxel sizes are recommended, particularly in maxillary molars and cases involving root canal treatment. However, these findings were obtained under controlled laboratory conditions using artificially created perforations and clinical validation is warranted. These findings highlight the importance of using CBCT judiciously and within appropriate indications for the early detection and accurate characterization of furcation perforations. Clinical studies are needed to validate these results in vivo.