AbstractAim: To assess resistance to cyclic fatigue of three brands of NiTi files after immersion in NaOCl solutions in conditions similar to those used in clinical practice.Methodology: A total of 150 new Twisted File (SybronEndo, Orange, California), Revo S SU (Micro Mega, Besançon, France) and Mtwo (Sweden&Martina, Due Carrare - Padova, Italy) endodontic NiTi rotary files size 25.06 taper were used. The fifty files of the same brand were randomly assigned to five different groups of 10 each. Group 1 (control group) was composed of new instruments not immersed in solution. Instruments of groups 2, 3, 4 and 5 were immersed in 5% NaOCl (Niclor, OGNA laboratory, Muggiò - Milano, Italy) at 37 °C for 16 mm. Files of Group 2 and 3 were statically immersed in NaOCl solution for 5 and 1 minutes respectively; instruments of Group 4 and 5 were dynamically (300 rpm/min) immersed in solution for 5 and 1 minutes respectively. All files were submitted to cyclic fatigue test and numbers of cycles to failure (NCF) were recorded. Data were analysed by Two way ANOVA (P < 0.05).Results: There's not statistical differences between the five groups of the same brand but Post-hoc analysis revealed a signiﬁcantly higher resistance to cyclic fatigue in all groups of Twisted File when compared to respective groups of Revo S SU (P < 0.001 for each comparison). The comparison between the same groups of Twisted File and Mtwo or Mtwo and Revo S did not show statistically significant differeces (P>0.05) Conclusions: In our experimental conditions immersion in sodium hypochlorite as in clinical practice not significatively reduce the cyclic fatigue resistance of nickel-titanium instruments. However, the cyclic fatigue changes with the type of instruments. In particular, Twisted File were more resistant. Furthermore static or dynamic immersion did not reduce significatively the cyclic fatigue resistance of the same endodontic file.
|Titolo:||Cyclic Fatigue resistance of three different nickel - titanium instruments after immersion in sodium hypochlorite|
|Data di pubblicazione:||2011|
|Appare nelle tipologie:||4.3 Poster|