title: Healing outcomes of root canal treatment for C-shaped mandibular second molars: a retrospective analysis.
abstract: OBJECTIVE
  This study aimed to evaluate the healing rate of non-surgical endodontic treatment between C-shaped and non-C-shaped mandibular second molars.
  
  
  METHODS
  Clinical records and radiological images of patients who had undergone endodontic treatment on mandibular second molars between 2007 and 2014 were screened. The periapical index scoring system was applied to compare healing outcomes. Information about preoperative and postoperative factors as well as the demographic data of the patients was acquired and evaluated using chi-square and multinomial logistic regression tests.
  
  
  RESULTS
  The total healing rate was 68.4%. Healing rates for the mandibular second molar were 70.9% in C-shaped canals (n= 79) and 66.6% in non-C-shaped ones (n= 117). The difference was not statistically significant.
  
  
  CONCLUSIONS
  The presence of a C-shaped canal in the mandibular second molar did not have a significantly negative effect on healing after treatment. Instead, proper pulpal diagnosis and final restoration were indicated as having significantly greater influence on the healing outcomes of C-shaped and non-C-shaped canals, respectively.
authors.affiliation: Department of Conservative Dentistry, Wonkwang University Daejeon Dental Hospital, Daejeon, Korea.
authors.forename: Hye-Ra
authors.initials: HR
authors.lastname: Ahn
authors.affiliation: Department of Conservative Dentistry, Wonkwang University Daejeon Dental Hospital, Daejeon, Korea.
authors.forename: Young-Mi
authors.initials: YM
authors.lastname: Moon
authors.affiliation: Department of Conservative Dentistry, Wonkwang University Sanbon Dental Hospital, Gunpo, Korea.
authors.forename: Sung-Ok
authors.initials: SO
authors.lastname: Hong
authors.affiliation: Department of Conservative Dentistry, Wonkwang University Daejeon Dental Hospital, Daejeon, Korea.
authors.forename: Min-Seock
authors.initials: MS
authors.lastname: Seo
keywords: C-shaped canal; Endodontic treatment; Healing rate; Mandibular second molar; Periapical index