Abstract
The purpose of this study was to analyze various characteristics and classification of C-shaped root canals and evaluate the causes of endodontic failure of C-shaped root canals by examining the resected root surface with an endodontic microscope and a scanning electron microscope (SEM). Forty-two teeth with C-shaped root canals were included in this study and had undergone intentional replantation surgery. Before surgery, periapical radiography and cone-beam computed tomography were taken. The root canal configuration was analyzed and classified according to Melton's classification at coronal and apical level. After injection of 1 : 100,000 epinephrine with 2% lidocaine, the tooth was carefully extracted. After the root-end resection, the resected root surface was examined using an operating microscope and SEM. Mandibular second molars were most frequently involved teeth (90.4%). The most frequently observed root canal configurations were C1 at the coronal level (45.2%) and C3 at the apical 3 mm level (45.2%). The most common cause of failure for a C-shaped root canal treatment was a leaky canal (45.2%), followed by an isthmus (23.8%), missing canal, overfilling, and iatrogenic problems. In conclusion, C-shaped root canals were most frequently found in mandibular second molars. The most common cause of failure was a leaky canal and isthmus.
Highlights
The C-shaped root canal system is an anatomical variant of the root canal structure, whose characteristic feature is the connection of the root canals by a fin or web-like structure to form a C shape at the root canal orifice [1]
They can be found in maxillary first molars [7,8,9], maxillary second molars [10, 11], and mandibular first molars [12, 13]
The most common cause of endodontic failure of C-shaped root canals was a leaky canal (45.2%), followed by an isthmus (23.8%), missing canal (9.5%), overfilling (7.1%), and iatrogenic problems (7.1%) (Figure 3, p < 0 05)
Summary
The C-shaped root canal system is an anatomical variant of the root canal structure, whose characteristic feature is the connection of the root canals by a fin or web-like structure to form a C shape at the root canal orifice [1]. A high prevalence of C-shaped root canals has been reported in mandibular second molars in the Asian population [3,4,5,6]. They can be found in maxillary first molars [7,8,9], maxillary second molars [10, 11], and mandibular first molars [12, 13]. Failures can be caused by procedural errors such as root perforation, separated instruments, or missed canals. The thin dentinal wall of the buccal or lingual groove may lead to strip perforation, which poses a considerable threat to tooth prognosis [4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
