1. Cyclic fatigue resistance of rotary NiTi instruments after simulated clinical use in curved root canals
- Author
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Giulio Gavini, Oscar Faciola Pessoa, and Juliana Melo da Silva
- Subjects
Models, Anatomic ,Cyclic stress ,medicine.medical_specialty ,Time Factors ,Rotation ,Root canal ,Root (chord) ,Entodontia ,root canal ,Cavidade pulpar ,Endodontics ,Fatigue resistance ,Nickel ,medicine ,Humans ,CANAL RADICULAR ,General Dentistry ,Mathematics ,rotary files ,Orthodontics ,Titanium ,nickel-titanium ,Instrumentos odontológicos ,Equipment Design ,cyclic fatigue ,Níquel-titânio ,Surgery ,Instrumentos rotatórios ,Equipment failure ,medicine.anatomical_structure ,Nickel titanium ,Equipment Failure ,Stress, Mechanical ,Dental Pulp Cavity ,Fadiga cíclica ,Root Canal Preparation ,Dental Alloys - 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. Resumo O objetivo deste estudo foi avaliar a resistência à fadiga cíclica de instrumentos rotatórios de níquel-titânio após simulação de uso clinico em canais curvos (curvatura de 40° e raio de 5 mm). Trinta e seis instrumentos, calibre n° 25 conicidade 0,04, foram divididos em três grupos: o Grupo A com um ciclo de uso; Grupo B, três ciclos de uso e grupo C, cinco ciclos de uso. Um cronômetro digital aferiu em segundos o tempo até a fratura do instrumento que, posteriormente, foi convertido em número de ciclos para fratura. Os dados foram analisados por ANOVA e teste de Tukey (p
- Published
- 2013