title: The effect of rubber dam usage on the survival rate of teeth receiving initial root canal treatment: a nationwide population-based study.
abstract: BACKGROUND
  It is well-known that the usage of rubber dams during root canal treatment (RCT) improves infection control and treatment efficacy and protects patients. However, the effect of rubber dam usage on endodontic outcomes remain uncertain. The aim of the present study was to investigate whether rubber dam usage affects the survival rate of initial RCT using a nationwide population-based database.
  
  
  METHODS
  A total of 517,234 teeth that received initial RCT between 2005 and 2011 met the inclusion criteria and were followed until the end of 2011. Univariate and multivariate Cox proportional hazards models were used to estimate the effects of rubber dam usage on the risk of tooth extraction after initial RCT.
  
  
  RESULTS
  Of the 517,234 teeth, 29,219 were extracted, yielding a survival rate of 94.4%. The survival probability of initial RCT using rubber dams after 3.43 years (the mean observed time) was 90.3%, which was significantly greater than the 88.8% observed without the use of rubber dams (P < .0001). After adjusting for age, sex, tooth type, hospital level, tooth scaling frequency per year after RCT, and systemic diseases, including diabetes and hypertension, the tooth extraction hazard ratio for the RCT with rubber dams was significantly lower than that observed for RCT without rubber dams (hazard ratio = 0.81; 95% confidence interval, 0.79-0.84).
  
  
  CONCLUSIONS
  The use of a rubber dam during RCT could provide a significantly higher survival rate after initial RCT. This result supports that rubber dam usage improves the outcomes of endodontic treatments.
authors.affiliation: Department of Dentistry, School of Dentistry, National Yang-Ming University, Taipei, Taiwan; Department of Dentistry, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
authors.forename: Po-Yen
authors.initials: PY
authors.lastname: Lin
authors.affiliation: Department of Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan.
authors.forename: Shih-Hao
authors.initials: SH
authors.lastname: Huang
authors.affiliation: Department of Dentistry, Cheng Hsin General Hospital, Taipei, Taiwan. Electronic address: ch9350@chgh.org.tw.
authors.forename: Hong-Ji
authors.initials: HJ
authors.lastname: Chang
authors.affiliation: Department of Dentistry, School of Dentistry, National Yang-Ming University, Taipei, Taiwan. Electronic address: chily@ym.edu.tw.
authors.forename: Lin-Yang
authors.initials: LY
authors.lastname: Chi
mesh_terms: D000328:Adult; D000367:Age Factors; D003324:Coronary Artery Disease / Q000453:epidemiology; D012534:Dental Scaling / Q000706:statistics & numerical data; D003922:Diabetes Mellitus, Type 1 / Q000453:epidemiology; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006949:Hyperlipidemias / Q000453:epidemiology; D006973:Hypertension / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D016016:Proportional Hazards Models; D019233:Retreatment; D012390:Root Canal Therapy / Q000706:statistics & numerical data*; D016733:Rubber Dams / Q000706:statistics & numerical data*; D016019:Survival Analysis; D013624:Taiwan / Q000453:epidemiology; D014081:Tooth Extraction / Q000706:statistics & numerical data; D016896:Treatment Outcome; D055815:Young Adult
keywords: Initial root canal treatment; rubber dam; survival analysis; survival rate