Clinical diagnosis and treatment of root canal system of mandibular second molars

AIM:To discuss the clinical diagnosis and treatment of root canal system of mandibular second molars.METHODS:The root canals of 127 mandibular second molars were determined by X-ray films and canal exploration.The root canals were instrumented by Ni-Ti rotary instruments Hero 642,and obturated with vertical condensation technique. The efficiency of preparation and obturation was analyzed with radiographs before and after treatment.RESULTS:The frequency of separate 3 root canals in mandibular second molars was 54.3%,separate 2 root canals was 11.0 %,a single canal was 3.1%,and C-shaped canals was 31.5 %.Most C-shaped canals were type Ⅰand Ⅱ.In X-ray films,the teeth having fused roots always had C-shaped canals.However,the teeth that revealed the distinct mesial and distal roots might have C-shaped canals.No complication,such as transportation,ledge and perforation,was found.Good result of treatment was achieved in almost all cases.CONCLUSION:The most of root canal system of mandibular second molars was separate 3 root canals.The C-shaped canal system made up the second.The C-shaped root canals could be diagnosed by X-ray films and canal exploration.With Ni-Ti rotary instrumentation and vertical condensation technique,the mandibular second molars can be treated very well.