PMC4751210_01
Root canal treatment of the C-shaped left mandibular second premolar with four canals and three apical foramina. (a) A preoperative periapical radiograph; (b) Master cone fit; (c, d) Postoperative periapical radiographs showing mesial and mesiobuccal canals joining in the coronal third of the root.
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F1
Clinical and radiographic examination revealed occlusal caries approaching the pulp horn in tooth #35 and no periapical radiolucency around the root apex of tooth #35 (Figure 1a). AH26 sealer (Dentsply Maillefer) using a warm vertical compaction technique (Figures 1b and 1c). A cotton pellet was placed in the pulp chamber, and the tooth was temporized with TERM (Dentsply Maillefer) (Figure 1d).
A CBCT scan and access cavity of the C-shaped left mandibular second premolar. (a) Axial view showing four canals in the C-shaped left mandibular second premolar; (b) Occlusal view of access cavity showing a C-shaped root canal configuration; (c) Axial view showing bilateral C-shaped mandibular first and second premolars; (d) Axial, panoramic, and sagittal views showing a fused root configuration of the left mandibular second premolar; (e) Axial view showing a measurement of root thicknesses around canals. The root thicknesses were measured individually at all levels with 0.3 mm interval from each canal to the outer surface of the root, and from the apical foramina to the canal orifices.
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F2
A long pulp chamber with a C-shaped canal configuration was identified under a dental operating microscope (Carl Zeiss Meditec Inc., Dublin, CA, USA, Figure 2b). The scan confirmed a C-shaped canal morphology with four canals (Figure 2a) and a fused root configuration (Figure 2d). The root thicknesses around all canals were measured at all levels, from the apical foramina to the canal orifices, in 0.3 mm interval from the outer surface of the root (Figure 2e). The presence of C-shaped canal morphology in teeth #34, 44, and 45 was incidentally identified in the scan images (Figure 2c).