Cyclic fatigue using severely curved canals and torsional resistance of thermally treated reciprocating instruments
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To evaluate the cyclic fatigue using severely curved canals and torsional resistance of ProDesign R (Easy Equipamentos Odontológicos, Belo Horizonte, MG, Brazil), Reciproc Blue (VDW, Munich, Germany), and WaveOne Gold (Dentsply Maillefer, Ballaigues, Switzerland) reciprocating instruments
Materials and methods
Twenty instruments of the ProDesign R (25/0.06) system, 20 instruments of the Reciproc Blue (25/0.08v) system, and 20 instrument of the WaveOne Gold (25/0.07v) system were used. Cyclic fatigue resistance was tested measuring the time to fracture and the number of cycles to fracture in an artificial stainless steel severely curved canal with 80° angle and a 3-mm radius of curvature (n = 10). Torque and angle of rotation at failure of new instruments (n = 10) were measured according to ISO 3630-1. The fracture surfaces of all fragments were examined with a scanning electron microscope. Results were statistically analyzed using one-way ANOVA and Tukey’s test at a significance level of p < 0.05.
ProDesign R instruments showed a significantly longer cyclic fatigue life than the other tested instruments (p < 0.05). Reciproc Blue showed longer cyclic life than WaveOne Gold (p < 0.05). Reciproc Blue showed the higher torsional strength, followed by WaveOne Gold and ProDesign R instruments (p < 0.05). Moreover, Reciproc Blue showed significantly higher angular rotation to fracture than ProDesign R (p < 0.05). WaveOne Gold showed intermediary results regarding angular rotation to fracture with no differences when compared to Reciproc Blue or ProDesign R instruments (p < 0.05).
ProDesign R presented the highest cyclic fatigue resistance in severely curved canals when compared with Reciproc Blue and WaveOne Gold. However, Reciproc Blue showed the higher torsional strength overall and higher angular rotation to fracture when compared to ProDesign R.
Despite the numerous advantages of reciprocating instruments, these instruments still have some risk of fracture during its use, especially in severely curved canals. The present study evaluated the cyclic fatigue and torsional resistance of thermally treated reciprocating instruments.
KeywordsCyclic fatigue Torsional resistance Thermal treatment Reciprocating instruments
This study was partially funded by FAPERJ.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
For this type of study, formal consent is not required.
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