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Safe pseudoelastic limit range under torsional loading with Reciproc Blue
J-H Ha1, G De-Deus2, A Versluis3
1Department of Conservative Dentistry, School of Dentistry, Kyungpook National University, Daegu, Korea.
International Endodontic Journal
|July 25, 2018
Summary
Reciproc Blue instruments exhibit a higher distortional angle at their pseudoelastic limit compared to original Reciproc files. However, the 170° pre-set angle of dedicated endodontic motors is safe for Reciproc Blue instruments during single or time-restricted use.
Area of Science:
- Endodontics
- Materials Science
- Biomedical Engineering
Background:
- Reciproc instruments are widely used in endodontic treatments.
- Reciproc Blue instruments offer enhanced flexibility and cyclic fatigue resistance.
- Understanding the mechanical properties of endodontic files under torsional load is crucial for clinical safety.
Purpose of the Study:
- To determine the distortional angle and torsional load at the pseudoelastic limit of Reciproc Blue instruments.
- To evaluate the safety of using pre-set dedicated motors (170°) with Reciproc Blue instruments.
- To compare the torsional properties of Reciproc Blue and original Reciproc instruments.
Main Methods:
- Testing of Reciproc R25 and Reciproc Blue R25 instruments under two torsional conditions: repetitive loading and single continuous rotation until fracture.
- Determination of pseudoelastic limits from torque-rotation curves.
- Statistical analysis using two-way ANOVA and t-tests.
- Examination of instrument surfaces using field-emission scanning electron microscopy (FE-SEM).
Main Results:
- Reciproc Blue instruments demonstrated a significantly greater angle at the pseudoelastic limit than original Reciproc instruments (P < 0.05).
- Repetitive torsional loading resulted in significantly lower torsional resistance compared to single continuous rotation (P < 0.05).
- Under all tested conditions, the pseudoelastic limit remained below the 170° pre-set angle of the dedicated motor.
- FE-SEM revealed microcracks and distorted machining grooves on Reciproc Blue instruments after torsional testing.
Conclusions:
- The 170° pre-set angle of dedicated endodontic motors is safe for Reciproc Blue instruments in single or time-restricted applications.
- Reciproc Blue instruments possess superior torsional properties compared to original Reciproc files.
- While Reciproc Blue instruments show resilience, microstructural analysis indicates potential for damage under prolonged or repetitive torsional stress exceeding their limit.
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