Assessment of the Quality of Root Canal Fillings-An Ex-Vivo Comparison of CBCT Scans, Conventional Intraoral Sensors, and a Novel Photon-Counting Sensor.

Abstract

Objectives: To compare a novel photon-counting sensor, two CBCT protocols and two CMOS sensors on the detection of gaps between a gutta-percha cone and root canal walls.

Methods: Twenty-five mandibular incisors were prepared to 45/.04 (size/taper) at working length. Teeth were placed in a partially dentate mandible and single gutta-percha cones of seven sizes were placed at length, one at a time, for image acquisition with a photon-counting sensor, two CBCT protocols (90µm3, 120µm3) and two CMOS sensors. Three calibrated observers assessed images for gap presence. Sensitivity, specificity, accuracy, AUC, and agreement with gold standard were determined using ANOVA and Tukey test (p ≤ 0.05).

Results: Photon-counting sensor showed superior sensitivity and accuracy (88.47%, 81.57%), significantly higher than the CBCT protocols (50.70-56.33%, 45.87-53.17%). Contrarily, the photon-counting sensor showed the lowest specificity (40.27%), significantly lower than the CBCT protocols (90.27%, 97.23%). CMOS sensors showed sensitivity, specificity, and accuracy between 72.23-74.53%, not differing from other modalities. All intraoral sensors showed AUC around 82.87-84.03%, significantly higher than CBCT protocol 120µm3 (74.07%). The file size was inversely related to gap size and percentual agreement with gold standard.

Conclusions: CMOS sensors showed consistent results, while the photon-counting sensor had the highest sensitivity but lacked specificity. CBCT protocols excelled in specificity but had lower sensitivity.

Advances in knowledge: Novel photon-counting sensors and CBCT imaging provided no significant advantage over conventional sensors in assessing gaps as an indicator of quality of root canal filling. Furthermore, smaller gaps were more difficult to detect, regardless of the imaging technique used.