PMC5379825_01
Radiographic features of the mandibular right first molar. (a) Diagnostic radiograph before treatment. (b) Postoperative radiograph. Symptoms were relieved after root canal treatment
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F1
No specific problem could be seen on the diagnostic radiograph [Figure 1a]. After irrigation with NaOCl and 17% ethylenediaminetetraacetic acid (Endo-prep Gel, Mediclus, Cheongju, Korea), all canals were dried and filled with gutta-percha and resin-based sealer (AHplus; Dentsply-Caulk, Konstanz, Germany) using the warm vertical compaction technique (Endo-Apex; EPdent, Seoul, Korea) [Figure 1b].
Radiograph at revisit after 6 months. Note the J-shaped periradicular radiolucency around the entire mesial root (white triangle)
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F2
Radiographic examination revealed extensive J-shaped periodontal bone loss around the mesial root [Figure 2].
Clinical photographs of extracted tooth. (a) The extracted tooth showing a definite fracture line on the mesial root (white triangle). (b) The fracture line became more obvious after methylene blue staining (black triangle)
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F3
We found a fracture line on the mesial root [Figure 3a]. The fracture line appeared more clearly when we stained it with 1% methylene blue solution [Figure 3b].
Stereomicroscopic view of the sectioned mesial root. Note the definite crack line containing gutta-percha (white triangles) (x20)
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F4
Notably, we found gutta-percha in the fracture line [Figure 4].