title: Survival Rate of Teeth with a C-shaped Canal after Intentional Replantation: A Study of 41 Cases for up to 11 Years.
abstract: BACKGROUND
  Teeth with a C-shaped canal have been regarded as a challenge for nonsurgical root canal treatment (RCT) and apical microsurgery because of their anatomic variations and low accessibility. For such teeth, intentional replantation might be a treatment option. The purpose of this study was to investigate the prognostic factors for the clinical outcome of intentionally replanted teeth with a C-shaped canal.
  
  
  METHODS
  We retrospectively investigated patients who had undergone intentional tooth replantation at the Department of Conservative Dentistry, Yonsei University Dental Hospital, Seoul, Korea, from June 2002 to November 2015. Consequently, 41 intentionally replanted teeth with C-shaped canals were identified. The cumulative survival rate and related prognostic factors were assessed based on clinical and radiographic examination using survival analysis.
  
  
  RESULTS
  The cumulative survival rate of intentionally replanted teeth with a C-shaped canal was 83.4% at 4 years and 73.0% at 11 years postoperatively. Based on Cox proportional hazard regression analysis, extraoral time (≤15 minutes vs >15 minutes) and retrofilling material (ProRoot MTA [Dentsply, Tulsa, OK] vs others) were significantly associated with tooth survival (P < .05).
  
  
  CONCLUSIONS
  Extraoral time exceeding 15 minutes and the use of ProRoot MTA as a retrofilling material were significantly associated with a lower survival of intentionally replanted teeth with C-shaped canals. With improved clinical procedures based on an understanding of the prognostic factors, intentional replantation would be a favorable treatment option for treating teeth with a C-shaped canal.
authors.affiliation: Microscope Center, Department of Conservative Dentistry and Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Korea.
authors.forename: Youngjune
authors.initials: Y
authors.lastname: Jang
authors.affiliation: Microscope Center, Department of Conservative Dentistry and Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Korea.
authors.forename: Seung-Jong
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Deptartment of Conservative Dentistry and Endodontics, National Health Insurance Service Ilsan Hospital, Goyang, Korea.
authors.forename: Tai-Cheol
authors.initials: TC
authors.lastname: Yoon
authors.affiliation: Microscope Center, Department of Conservative Dentistry and Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Korea.
authors.forename: Byoung-Duck
authors.initials: BD
authors.lastname: Roh
authors.affiliation: Microscope Center, Department of Conservative Dentistry and Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Korea. Electronic address: andyendo@yuhs.ac.
authors.forename: Euiseong
authors.initials: E
authors.lastname: Kim
mesh_terms: D000328:Adult; D003786:Dental Pulp Cavity / Q000002:abnormalities* / Q000601:surgery; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D014090:Tooth Replantation / Q000009:adverse effects / Q000379:methods*; D016896:Treatment Outcome
keywords: Extraoral time; mineral trioxide aggregate; root canal anatomy; survival analysis; tooth replantation