title: Pain after single-visit root canal treatment with two single-file systems based on different kinematics--a prospective randomized multicenter clinical study.
abstract: OBJECTIVE
  The aim of this study is to evaluate the posttreatment pain after instrumentation of root canals with a single-file reciprocating (RECIPROC, VDW, Germany) or rotary (One Shape, MicroMega, France) file system.
  
  
  METHODS
  Six hundred forty patients were assessed for eligibility, and 624 patients were included in this study. The teeth were randomly allocated to one of the instrumentation protocols. The teeth underwent routine root canal treatment after which patients were discharged with a questionnaire to gather data about the incidence (yes/no), nature (mild, moderate, or severe), and duration of pain (days). The data were analyzed using statistical analyses (preoperative pain scores by Mann-Whitney U test, incidence and intensity of pain by chi-squared test, intake of analgesics, and duration of pain by Student's t test) with P = 0.05.
  
  
  RESULTS
  Pain analysis was performed for 605 patients (311 males and 294 females) as 5 patients were excluded due to sealer extrusion and 14 were lost to follow-up. The mean age of the patients was 31 ± 2 years. There was significant difference in the incidence of postoperative pain (P < 0.001). There was significant difference in the number of patients who had mild (P = 0.001), moderate (P = 0.002), and severe (P = 0.001) pain between the two groups. Intensity of pain showed significant difference, with patients in the One Shape group (40.5 %) reporting more values of severe pain (P = 0.002); the percentage of patients who took analgesics was significantly higher in the One Shape group (40.5 %) than in the Reciproc group (19.3 %) (P = 0.002). There was no significant difference in the duration of postoperative pain between the two groups when the pain was mild (P = 0.301), but One shape showed significantly longer duration of moderate (P = 0.001) and severe pain (P = 0.002).
  
  
  CONCLUSIONS
  Reciproc showed significantly less intensity and duration of posttreatment pain compared to One Shape.
  
  
  CONCLUSIONS
  Reciprocation movement offers a more predictable and safer approach of root canal preparation, in addition to producing less postoperative pain. The need for patients to take analgesics may reduce following this approach.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Saveetha Dental College and Hospitals, Saveetha University, Chennai, India. prasanna_neelakantan@yahoo.com.
authors.forename: Prasanna
authors.initials: P
authors.lastname: Neelakantan
authors.affiliation: Department of Conservative Dentistry and Endodontics, Saveetha Dental College and Hospitals, Saveetha University, Chennai, India.
authors.forename: Subash
authors.initials: S
authors.lastname: Sharma
mesh_terms: D000328:Adult; D003762:Dental Instruments; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D010147:Pain Measurement; D010149:Postoperative Pain / Q000209:etiology*; D011446:Prospective Studies; D012307:Risk Factors; D012390:Root Canal Therapy / Q000295:instrumentation*; D011795:Surveys and Questionnaires
keywords: Nickel-titanium; One Shape; Pain; RECIPROC; Randomized clinical trial; Reciprocation; Root canal preparation; Rotary