Objective To compare and analyze the performances of radio visio graphy (RVG), cone-beam computed to-mography (CBCT), and transparent teeth in diagnosing the first molar root canal system in vitro; to provide an anatomical image of the first molar root canal therapy and analyze the relationship between the first molar root canal image and root canal anatomy.Methods A total of 269 extracted first molars were examined by RVG and CBCT in the mesiodistal and buccolin-gual sections. Transparent teeth were then constructed using dying root canals. The root canal system and the communicating branches between the pipes of the coronal 2/3 and apical 1/3 areas of each root canal were displayed using RVG, CBCT, and transparent teeth. The performance of CBCT in the diagnosis was evaluated.Results The display rate of the first molar root (coronal 2/3) was 96.55% in CBCT. A significant difference was found between CBCT and the transparent teeth in the apical 1/3 area of the first molars (PConclusion CBCT and transparent teeth exhibit nearly equal performance in displaying the coronal 2/3 area of the root canal system. However, the performance of transparent teeth in displaying the apical 1/3 area is higher than that of CBCT. Meanwhile, the RVG-provided display of the multiroot canal and bifurcate root canals is limited. The incidence rates of double or multiroot canals and pipe transport in the mesial roots of the mandibular and maxillary first molars are high. CBCT has numerous advantages in dis-playing the root canal; it is also the most reliable method for diagnosing root diseases without trauma.
