Abstract:

[Abstract]   Objective   To investigate the incidence of C-shaped root canal systems in mandibular second perma?
nent molar of patients in the First People’ s Hospital of Yunnan Province, and compare the success rate between one- and two-visit root canal treatment.   Methods   Two hundred and sixty mandibular second molars were recruited from the patients in the department of endodontics of our hospital, and teeth with C-shaped root canal were categorized by using radio?graphic classification criteria and the modified Melton’ s method. Teeth with C-shaped root canal systems were then randomly divided into two groups to receive one- or two-visit root canal treatment, and success rates of 6-month post-operation were compared between two groups.   Results   Eighty out of 260 mandibular second molars exhibited C-shaped canals (30.77%). Radiographic examination showed that 25 teeth belonged to type Ⅰ (31.25%), 32 teeth type Ⅱ (40.00%) and 23 teeth type Ⅲ (28.75%) in two groups. As for modified Melton’ s method, the incidence rates were 21.25%, 48.75%, 16.25% and 13.75% for C1,C2,C3a and C3b, respectively, while C4 was not found. The success rates were 78.94% (30/38) and 81.08% (30/37) for A group and B group, respectively, with no statistically significant difference between two groups (78.94 vs 81.08, P > 0.05).   Conclusion   Results indicate a frequent incidence of C-shaped root canal system of mandibular permanent second molars in our hospital. One-visit root canal treatment is an effective way for treating C-shaped canals in mandibular permanent second molar.

Key words: Mandibular second permanent molars, C-shaped root canal system, one-visit root canal treatment