Clinical diagnosis and treatment of C-shaped root canals in mandibular second molars

Objective To discuss the incidence,diagnosis,and treatment of C-shaped root canals in mandibular second molars.Methods The C-shaped root canals in 130 cases of mandibular second molars were diagnosed by X-ray films and canal exploration using Melton's method.The root canals were shaped by using Ni-Ti rotary instruments and using the so-called drawing-fish-net'root canal preparation technique,cleaned by using ultrasonic irrigation with sodium hypochorite,and obturated with vertical condensation technique for C-shaped root canals.The efficiency of preparation and obturation was analyzed with radiographs before,during and afer operation.The prognosis was evaluated by patients'signs,clnical examination,and recall radiographs.Results The frequency of C-shaped canals in mandibular second molars was 26.9%.According to the X-ray films,79.6% of teech with C-shaped canals had fused roots,and 20.4% of C-shaped canals teech revealed the distinct mesial and distal roots.There was no any complication in all cases.The result of treatment was good.Conclusion The C-shaped canal system in mandibular second molars has the radiograph image showing a fused root or distinct mesial and distal roots,which could be diagnosed by X-ray films and canals exploration.The C-shaped mandibular second molars can be treated very well with rotary instrumentation,the so-called drawing-fishnet's root canal preparation technique,ultrasonic irrigation with sodium hypochlorite,and vertical condensation technique.