title: Influence of operator's experience level on lifespan of the WaveOne Primary file in extracted teeth.
abstract: OBJECTIVE
  The aim of this study was to assess the influence of operator experience level on the lifespan of the WaveOne Primary file (Dentsply Maillefer, Ballaigues, Switzerland) in extracted teeth.
  
  
  METHODS
  Moderately curved canals of extracted maxillary and mandibular molars were randomly distributed into 2 groups: experienced and inexperienced operators. Ten files were allocated to each group (n = 10). Each canal was prepared until the working length was reached, and the same file was used to prepare additional canals until it separated. The number of canals prepared before file separation was recorded. The fragment length of each file was measured, and the location of the fragment in the canal was determined. Data were statistically analysed using the independent 2-sample t-test.
  
  
  RESULTS
  The 2 operators prepared a total of 324 moderately curved canals of maxillary and mandibular molars. There was no significant intergroup difference in the mean number of canals prepared (p = 0.27). The average lifespan of the WaveOne Primary file was 17.1 and 15.3 canals, and the longest lifespan was 25 and 20 canals, when used by experienced and inexperienced operators, respectively. There were no statistically significant intergroup differences in separated fragment length and location.
  
  
  CONCLUSIONS
  Within the limitations of this study, operator experience level appears to have no effect on the lifespan of the WaveOne Primary file in preparation of moderately curved canals. Single teeth with multiple canals can be prepared safely even by a novice operator by using a single file.
authors.affiliation: Department of Restorative Dentistry, Ajman University of Science and Technology, Ajman, United Arab Emirates.
authors.forename: Abdulrahman Mohammed
authors.initials: AM
authors.lastname: Saleh
authors.forename: Saeid
authors.initials: S
authors.lastname: Tavanafar
authors.forename: Pouyan
authors.initials: P
authors.lastname: Vakili-Gilani
authors.forename: Noor Jamal
authors.initials: NJ
authors.lastname: Al Sammerraie
authors.forename: Faahim
authors.initials: F
authors.lastname: Rashid
keywords: Lifespan; Operator experience; Reciprocating; Separation; WaveOne