Bending Resistance and Dynamic and Static Cyclic Fatigue Life of Reciproc and WaveOne Large Instruments

By De-Deus G, Leal Vieira VT, Nogueira da Silva EJ, Lopes H, Elias CN, Moreira EJ

Date: 08/2014
Journal: JOE

Summary:

Purpose: To evaluate the bending resistance and the dynamic and static cyclic fatigue life of Reciproc R40 and WaveOne large instruments.

N=  68 NiTi instruments for use under reciprocation movement (Reciproc and WaveOne)

Materials/Methods:

  • Reciproc R40( 0.06 taper) and WaveOne (0.08 taper), both had a tip  of 0.40 mm were selected.

  • Bending resistance was performed in 10 instruments of each system by using a universal testing machine

  •  In 4 experimental groups (n = 12), Dynamic and static models for cyclic fatigue testing were performed by using a custom-made device on an artificial canal measuring

  • Time was recorded as a fracture was detected visually or audibly. A video recording was performed.

     

Most highlighted Results:

  • WaveOne instruments presented significantly higher bending resistance than Reciproc
  • Reciproc revealed a significantly longer cyclic fatigue life in both static and dynamic tests that of the WaveOne.
  • The dynamic cyclic fatigue average time of Reciproc showed an increase of 31% compared with static test, whereas WaveOne instruments showed 22% improvement in time.
  • The average fatigue time of Reciproc instrument was 69% (static) and 73% (dynamic) greater than WaveOne.
  • SEM indicated that all instruments showed morphologic characteristics of ductile fracture.

Clinical Significance:

  • Instrument should not be static inside the root canal to reduce the risk of fracture. WaveOne larger instruments are less flexible than Reciproc R40 ones.