1. Cyclic fatigue resistance of rotary NiTi instruments after simulated clinical use in curved root canals.
- Author
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Pessoa OF, da Silva JM, and Gavini G
- Subjects
- Equipment Design, Equipment Failure, Humans, Models, Anatomic, Rotation, Stress, Mechanical, Time Factors, Dental Alloys chemistry, Dental Pulp Cavity anatomy & histology, Nickel chemistry, Root Canal Preparation instrumentation, Titanium chemistry
- Abstract
The aim of this study was to assess cyclic fatigue resistance in rotary nickel-titanium instruments after simulated clinical use in curved root canals (40-degree, 5-mm radius curve). Thirty-six RaCe rotary NiTi files, size #5, taper 0.04, were divided into 3 groups: Groups A, B and C with one, three and five cycles of use, respectively. Time to failure was recorded with a stopwatch in seconds and subsequently converted to number of cycles to fracture. The data were analyzed statistically by ANOVA and Tukey's test (α=0.05). Five sets of clinically used files (group C) reached significantly lower cycle-numbers before fracture (mean=197.5 cycles) when compared with one set of clinically used files (mean=309.2) and three sets (mean=287.5). Results showed that the number of simulated clinical uses of RaCe instruments for shaping curved canals affects adversely the fatigue resistance of these instruments after five uses.
- Published
- 2013
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