title: Cyclic fatigue of Reciproc and WaveOne reciprocating instruments.
abstract: OBJECTIVE
  To evaluate the cyclic fatigue resistance of Reciproc(®) and WaveOne(®) instruments in simulated root canals.
  
  
  METHODS
  Two groups of 15 NiTi endodontic instruments of identical tip size of 0.25 mm were tested, group A; Reciproc(®) R25 and group B: WaveOne(®) primary. Cyclic fatigue testing was performed in a stainless steel artificial canal manufactured by reproducing the instrument's size and taper. A simulated root canal with a 60° angle of curvature and 5-mm radius of curvature was constructed for both the instruments tested. The centre of the curvature was 5 mm from the tip of the instrument and the curved segment of the canal was approximately 5 mm in length. The Reciproc(®) instruments were activated using the preset programme specific for the Reciproc(®) instruments, whilst the WaveOne(®) instruments were activated using the preset programme specific for the WaveOne(®) instruments. All instruments were rotated until fracture occurred and the time to fracture (TtF) and the length of the fractured tip were recorded and registered. Means and standard deviations of TtF and fragment length were calculated for each system and data were subjected to Student's t-test (P < 0.05).
  
  
  RESULTS
  A statistically significant difference (P < 0.05) was noted between Reciproc(®) and WaveOne(®) instruments. Reciproc(®) R25 instruments were associated with a significant increase in the mean time to fracture when compared with primary WaveOne(®) instruments (130.8 ± 18.4 vs. 97.8 ± 15.9 s). There was no significant difference (P > 0.05) in the mean length of the fractured fragments between the instruments.
  
  
  CONCLUSIONS
  Reciproc(®) instruments were associated with a significantly higher cyclic fatigue resistance than WaveOne(®) instruments.
authors.affiliation: Department of Endodontics, Sapienza University of Rome, Via Tommaso Salvini 57, Rome, Italy. endo@gianlucaplotino.com
authors.forename: G
authors.initials: G
authors.lastname: Plotino
authors.forename: N M
authors.initials: NM
authors.lastname: Grande
authors.forename: L
authors.initials: L
authors.lastname: Testarelli
authors.forename: G
authors.initials: G
authors.lastname: Gambarini
mesh_terms: D003722:Dental Alloys; D003762:Dental Instruments; D003799:Dental Stress Analysis; D004867:Equipment Design; D004868:Equipment Failure; D006801:Humans; D009532:Nickel; D018915:Root Canal Preparation / Q000295:instrumentation*; D014025:Titanium
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium