Effect of A Clinical-Replicable Cooling Protocol on the Cyclic Fatigue Resistance of Heat-Treated Nickel-Titanium Instruments.

Autor:	Heck L; Department of Conservative Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil., Weissheimer T; Department of Conservative Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil., Souza Calefi PH; Department of Restorative Dentistry, Dental Materials and Endodontics, University of São Paulo, Bauru, São Paulo, Brazil., Alcalde MP; Health Science Center, Sacred Heart University, Bauru, São Paulo., Vivan RR; Department of Restorative Dentistry, Dental Materials and Endodontics, University of São Paulo, Bauru, São Paulo, Brazil., da Rosa RA; Department of Conservative Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil., Hungaro Duarte MA; Department of Restorative Dentistry, Dental Materials and Endodontics, University of São Paulo, Bauru, São Paulo, Brazil., Reis Só MV; Department of Conservative Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
Jazyk:	angličtina
Zdroj:	Iranian endodontic journal [Iran Endod J] 2022 Summer; Vol. 17 (3), pp. 132-137.
DOI:	10.22037/iej.v17i3.37210
Abstrakt:	Introduction: The aim of this study was to evaluate the bending and cyclic fatigue resistance of Wave One Gold (WOG) and X1 Blue (X1B) instruments when tested at body temperature (36°C ± 1°C) with and without subjected to an alloy cooling protocol. Materials and Methods: A total of sixty instruments (n=30) were tested. Forty instruments (n=20) were randomly selected and divided into two groups: body temperature (BT; n=20) and body temperature with cooling protocol (CP; n=20). Cyclic fatigue test was performed until fracture in a conventional stainless-steel device with water bath equipment to simulate body temperature. CP group instruments were subjected to 5 seconds of spray cooling every 30 seconds. Time to fracture was recorded in seconds. Resistance to bending at an angle of 45 degrees was evaluated using twenty instruments (n=10). Fractured surfaces were examined under scanning electron microscopy (SEM). Statistical analysis was performed at a 5% significance level. Results: There was no difference in the cyclic fatigue resistance between instruments in BT groups ( P >0.05). Cooling protocol significantly increased the cyclic fatigue resistance of X1B instruments ( P =0.0003) and WOG instruments ( P =0.0003). Results: WOG instruments had a significantly lower cyclic fatigue resistance compared to X1B instruments in CP group ( P =0.0001). There were no significant differences between the values of resistance increase presented by the instruments after cooling ( P >0.05). Bending test presented no statistically significant differences between the tested instruments ( P >0.05). Both instruments in both groups showed typical features of cyclic fatigue behavior under SEM. Conclusions: X1 Blue #25.06 and WaveOne Gold #25.07 instruments presented similar cyclic fatigue resistance. The investigated clinical-replicable cooling protocol improved the cyclic fatigue resistance of the tested instruments, with X1 Blue #25.06 presenting a greater cyclic fatigue resistance after cooling. Both instruments presented a similar bending capacity. Competing Interests: ‘None declared’.
Databáze:	MEDLINE
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