Comparative evaluation of cutting efficiency, cyclic fatigue, corrosion resistance, and autoclave cycle effects of three different file systems: An in-vitro micro-CT and metallurgy analysis

Aim: To compare the cutting efficiency, cyclic fatigue, corrosion resistance, and autoclave cycle effects of ProTaper Gold, TruNatomy, and WaveOne Gold file systems. Materials and Methods: Thirty mesiobuccal roots of extracted maxillary first molars were randomly divided into three groups (10 specimens each) for testing cutting efficiency: Groups A, B, and C: ProTaper Gold, TruNatomy-Prime, and WaveOne Gold-Primary, respectively. Root canal instrumentation was carried out in each root accordingly. Specimens’ weights were measured and micro-computed tomography was used to scan the samples before and after root canal preparation. For cyclic-fatigue, corrosion-resistance, and autoclave-cycle-effects testing, 30 files were allocated into three groups at random, Groups A, B, and C: ProTaper Gold-F2, TruNatomy-Prime, and WaveOne Gold-Primary (10 specimens each). For cyclic-fatigue testing, the instruments were firmly held in a stainless steel block with an artificial canal without pressure. The time (s) was calculated until fracture. For the corrosion-resistance test, SEM surface-topographical analysis was carried out in response to 5.25% NaOCl, 2% CHX, and 17% EDTA. For evaluation of autoclave cycle effects, SEM surface-topographical analysis was carried out for 1, 5, and 10 autoclave cycles. Data were analyzed statistically using one-way analysis of variance followed by multiple comparisons with Bonferroni’s test at P<0.05. Results: TruNatomy was the most resistant to cyclic fatigue and ProTaper Gold the least. WaveOne Gold removed significantly more dentin and had the least corrosion resistance and highest autoclave cycle effects. Conclusion: TruNatomy can be considered as a better file system compared with WaveOne Gold and has comparable efficiency with that of ProTaper Gold.