title: Decision Making for Retention of Endodontically Treated Posterior Cracked Teeth: A 5-year Follow-up Study.
abstract: BACKGROUND
  The study aimed to investigate the 5-year survival of root-filled posterior cracked teeth and its related factors.
  
  
  METHODS
  Two hundred patients who had root canal-treated posterior cracked teeth at the National Dental Centre were recalled for a 5-year review. Eighty-four patients who met the inclusion criteria were included in this study. The cases were managed following the treatment protocol for cracked teeth at the center. The data for analyses were obtained from the patients' clinical records. Statistical analyses were performed using SPSS 21.0 (SPSS Inc, Chicago, IL). The outcome measure was the presence of tooth at the time of the review.
  
  
  RESULTS
  At 5 years, 77 teeth "survived" (92%), and 7 teeth (8 %) were extracted. Patient demographics, tooth type and location, existing restoration, number and location of cracks, presence of pretreatment signs and symptoms, and initial pulpal and periapical diagnosis did not significantly affect the survival of the teeth. Univariate analysis showed that teeth with extension of the cracks onto the pulpal floor were more often extracted (odds ratio = 4.5, P = .07). Multivariable analyses found that extension of cracks onto the pulpal floor independently increased the odds of tooth loss by 11-fold (odds ratio = 11, P = .033), with other factors being held constant. The 5-year survival estimate in the absence and presence of crack extension onto the pulpal floor was 99% and 88%, respectively.
  
  
  CONCLUSIONS
  Coronal cracks may be predictably treated, whereas radicular cracks increased the odds of the tooth being extracted.
authors.affiliation: Department of Restorative Dentistry, National Dental Centre, Singapore. Electronic address: irene.sim.g.b@ndcs.com.sg.
authors.forename: Irene G B
authors.initials: IG
authors.lastname: Sim
authors.affiliation: Private Practice, Singapore.
authors.forename: Toh-Seong
authors.initials: TS
authors.lastname: Lim
authors.affiliation: Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, Singapore.
authors.forename: Gita
authors.initials: G
authors.lastname: Krishnaswamy
authors.affiliation: Department of Restorative Dentistry, National Dental Centre, Singapore.
authors.forename: Nah-Nah
authors.initials: NN
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001641:Bicuspid / Q000293:injuries*; D003387:Cracked Tooth Syndrome / Q000175:diagnosis / Q000628:therapy*; D003657:Decision Making; D003793:Dental Restoration, Permanent; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D008963:Molar / Q000293:injuries*; D012390:Root Canal Therapy / Q000379:methods* / Q000706:statistics & numerical data; D014092:Tooth Root / Q000293:injuries; D016896:Treatment Outcome; D055815:Young Adult
keywords: Cracked tooth; endodontic; failure rate; long-term survival