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:
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Reciproc R40( 0.06 taper) and WaveOne (0.08 taper), both had a tip of 0.40 mm were selected.
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Bending resistance was performed in 10 instruments of each system by using a universal testing machine
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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
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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.
