title: Treatment outcomes of single-visit versus multiple-visit non-surgical endodontic therapy: a randomised clinical trial.
abstract: BACKGROUND
  Clincians have been providing single-visit and multiple-visit endodontic treatments for their patients. This study aims to compare the success rate, prevalence of postoperative pain and chairside time of single-visit and multiple-visit endodontic treatments.
  
  
  METHODS
  Patients who required primary endodontic treatment in a university dental clinic were randomly allocated to two general dentists for single-visit or multiple-visit treatments using the same materials and procedures. Ni-Ti rotary files were used to prepare the root canals, which were subsequently obturated with a core-carrier technique. The chairside time was recorded. The treated teeth were followed up every 6 months on clinically signs and symptoms including pain, tenderness to percussion, sinus tract, mobility and abscess. Periapical radiographs were taken to assess periapical pathology. Successful treatments were neither clinical signs/symptoms noted nor radiographic periapical pathology found postoperatively.
  
  
  RESULTS
  A total of 220 teeth from patients aged 46.4 ± 14.1 were followed up for at least 18 months. The mean (±SD) follow-up period was 29.4 ± 9.3 months. The success rates of single-visit and multiple-visit treatments were 88.9 and 87.4 %, respectively (p = 0.729, effect size odds ratio = 1.156). Maxillary teeth had odds ratios of 3.16 (95 % CI: 1.33 to 7.46; p = 0.009) and absence of preoperative apical periodontitis had odds ratios of 4.35 (95 % CI: 1.43 to 13.24; p = 0.010) were identified from logistic regression as having a higher success rate. The average chairside times of single-visit and multiple-visit treatments were 62.0 and 92.9 min, respectively (mean difference = -30.9, 95 % CI: -39.4 to -22.4, p < 0.001, effect size odds ratio = -0.996). Single-visit and multiple-visit treatment had no significant difference in the prevalence of postoperative pain within 7 days (21 and 12 %, p = 0.055, effect size odds ratio = 2.061) and after at least 18 months (0.9 and 1.0 %, p > 0.999, effect size odds ratio = 0.879).
  
  
  CONCLUSIONS
  The success rate and prevalence of postoperative pain of single-visit or multiple-visit treatment had no significant difference. The chairside time for single-visit treatment was shorter than multiple-visit treatment.
  
  
  BACKGROUND
  Clinical Trials (WHO) ChiCTR-IOR-15006117 registered on 20 March 2015.
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Hong Kong, China. drawong@hku.hk.|University Health Service, The University of Hong Kong, Hong Kong, China. drawong@hku.hk.
authors.forename: Amy Wai-Yee
authors.initials: AW
authors.lastname: Wong
authors.affiliation: University Health Service, The University of Hong Kong, Hong Kong, China. cissytsang@yahoo.com.
authors.forename: Cissy Sung-Chi
authors.initials: CS
authors.lastname: Tsang
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Hong Kong, China. zhangsn2000@gmail.com.
authors.forename: Shinan
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Hong Kong, China. skyli@hku.hk.
authors.forename: Kar-Yan
authors.initials: KY
authors.lastname: Li
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Hong Kong, China. zhangcf@hku.hk.
authors.forename: Chengfei
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Faculty of Dentistry, The University of Hong Kong, Hong Kong, China. chchu@hku.hk.
authors.forename: Chun-Hung
authors.initials: CH
authors.lastname: Chu
mesh_terms: D000328:Adult; D006801:Humans; D008875:Middle Aged; D010146:Pain / Q000453:epidemiology*; D010147:Pain Measurement; D010485:Periapical Periodontitis / Q000517:prevention & control*; D012390:Root Canal Therapy / Q000379:methods*; D016896:Treatment Outcome