title: Identification of a C-shaped canal system in mandibular second molars-part II: the effect of bone image superimposition and intraradicular contrast medium on radiograph interpretation.
abstract: The purpose of this study was to investigate the effect of image superimposition from surrounding alveolar bone and intraradicular contrast medium on radiographic interpretation of a C-shaped canal system in mandibular second molars. Thirty mandibular second molars with fused roots were collected and stored in 10% formalin solution. After being scanned by microcomputed tomography and reconstructed, the buccal-lingual radiographs of each tooth were taken with or without intraradicular contrast medium and mandibular bony plates. The number of mesial and distal canals in the coronal-to-middle canal portion and the canal number in the apical 4-mm area were recorded. The buccal-lingual and three-dimensional view of reconstructed canal images were used to evaluate the accuracy of radiograph reading. The results were subjected to the Friedman and chi-square test. The results showed that without intraradicular contrast medium, the bone superimposition could decrease the accuracy of canal recognition significantly (p < 0.001), especially in the apical area. When contrast medium was in canals, the canal reading seemed not to be affected by the bone superimposition (p > 0.05). Based on these findings, the intraradicular contrast medium could increase the accuracy of canal recognition of a C-shaped canal system in mandibular second molars despite the bone image superimposition, especially in the detection of continuous C-shaped canals and the canals in the apical area.
authors.affiliation: Key Laboratory of Oral Biomedical Engineering of Ministry of Education, Endodontic Center, School and Hospital of Stomatology, Wuhan University, Wuhan, China. bingfan8@hotmail.com
authors.forename: Bing
authors.initials: B
authors.lastname: Fan
authors.forename: Yuan
authors.initials: Y
authors.lastname: Gao
authors.forename: Wei
authors.initials: W
authors.lastname: Fan
authors.forename: James L
authors.initials: JL
authors.lastname: Gutmann
mesh_terms: D000539:Alveolar Process / Q000000981:diagnostic imaging*; D019412:Anatomy, Cross-Sectional; D003287:Contrast Media; D003786:Dental Pulp Cavity / Q000002:abnormalities* / Q000000981:diagnostic imaging; D005671:Fused Teeth / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008334:Mandible / Q000000981:diagnostic imaging; D008963:Molar / Q000002:abnormalities* / Q000000981:diagnostic imaging; D011856:Radiographic Image Enhancement / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods; D014092:Tooth Root / Q000002:abnormalities* / Q000000981:diagnostic imaging
chemical_list: D003287:Contrast Media