The aim of this study was to evaluate the effect of different irrigation solutions used during root canal irrigation in root canal treatment on the microhardness of nickel-titanium (NiTi) files subjected to different heat treated. The pre-preparation microhardness levels of EndoArt Smart Blue and EndoArt Smart Gold (İnci Dental Productions Co, Istanbul, Turkey) file systems were measured at five different points using a microhardness testing device (HMV-2000; Shimadzu, Tokyo, Japan). Microhardness evaluation was performed on thirty-two 30.04 files from each file system. A total of 64 single-rooted and single-canaled mandibular incisor teeth were prepared up to size 30.04 using file systems. The preparation was completed with the irrigation solutions (5.25% NaOCl, 17% EDTA, ozonated water, and distilled water) for an average of 3 min with a 30.04 file. After preparation, the microhardness levels of the 30.04 files were again measured. The differences between the microhardness values were statistically compared. According to the obtained data, the pre-preparation measurement values were higher than the post-preparation values (p < 0.05). No statistically significant differences were found between the microhardness measurement values (p > 0.05). The highest and lowest microhardness changes were observed in the EndoArt Smart Blue file system, in the ozonated water (195.63 ± 71.04 VHN (Vickers Hardness Number)) and distilled water (152.88 ± 51.10 VHN) groups, respectively. In this study, different irrigation solutions did not have a statistically significant effect on the microhardness of heat-treated NiTi files.
PintoJCPivoto-JoãoMMBEspirCG, et al. Micro-CT evaluation of apical enlargement of molar root canals using rotary or reciprocating heat-treated NiTi instruments. J Appl Oral Sci2019; 27: e20180689.
2.
RadwańskiMŁęskiMPuszkarzAK, et al. Shaping ability of ProTaper next, HyFlex CM, and V-taper 2H nickel-titanium files in mandibular molars: a micro-computed tomographic study. Iran Endod J2021; 16: 103–108.
3.
SchäferEBürkleinS. Impact of nickel-titanium instrumentation of the root canal on clinical outcomes: a focused review. Odontology2012; 100: 130–136.
4.
SjogrenUHagglundBSundqvistG, et al. Factors affecting the long-term results of endodontic treatment. J Endod1990; 16: 498–504.
5.
SiqueiraJFJr.Aetiology of root canal treatment failure: why well-treated teeth can fail. Int Endod J2001; 34(1): 1–10.
6.
ChanWSGulatiKPetersOA. Advancing nitinol: from heat treatment to surface functionalization for nickel-titanium (NiTi) instruments in endodontics. Bioact Mater2023; 22: 91–111.
7.
KalyoncuoğluEKeskinCKeleşA, et al. Metallurgical characterisation and torsional resistance of blue thermomechanically treated nickel titanium instruments after simulated ex vivo retreatment procedure. Aust Endod J2022; 48: 121–130.
8.
GaoYGutmannJLWilkinsonK, et al. Evaluation of the impact of raw materials on the fatigue and mechanical properties of ProFile Vortex rotary instruments. J Endod2012; 38: 398–401.
9.
ShenYQianWAbtinH, et al. Effect of environment on fatigue failure of controlled memory wire nickel-titanium rotary instruments. J Endod2012; 38: 376–380.
10.
SridharMRYovanovichMM. Empirical methods to predict Vickers microhardness. Wear1996; 193: 91–98.
11.
ElnaghyAMElsakaSE. Assessment of the mechanical properties of ProTaper next nickel-titanium rotary files. J Endod2014; 40: 1830–1834.
12.
YeJGaoY. Metallurgical characterization of M-wire nickel-titanium shape memory alloy used for endodontic rotary instruments during low-cycle fatigue. J Endod2012; 38: 105–107.
13.
UsluGÖzyürekTYılmazK, et al. Effect of dynamic immersion in sodium hypochlorite and EDTA solutions on cyclic fatigue resistance of waveone and waveone gold reciprocating nickel-titanium files. J Endod2018; 44: 834–837.
14.
O’HoyPYMesserHHPalamaraJE. The effect of cleaning procedures on fracture properties and corrosion of NiTi files. Int Endod J2003; 36: 724–732.
15.
Al-AshouW. The effects of two root canal irrigants and different instruments on dentin microhardness: an in vitro study. Al-Rafidain Dent J2011; 11: 63–70.
16.
VeeraiyanMKumarYPChandharCY, et al. Evaluation of smear layer removal and micro hardness alteration of radicular dentin after using various chelating agents - an atomic force microscopic study. J Pharm Bioallied Sci2023; 15: S582–S587.
17.
PallewarAMGarlapatiRNageshB, et al. Effect of NaOCl and EDTA solutions on topography of ESX, TruShape and ProTaper Gold NiTi rotary instruments: an atomic force microscopic study. J Conserv Dent2019; 22: 459–463.
18.
ShaikIDasariBAlapatiS, et al. Effect of sterilization and irrigating solutions on nanostructure alteration of Ni-Ti rotary instruments in endodontics: an atomic force microscopic study. J Pharm Bioallied Sci2024; 16: S613–S618.
19.
MartinsJNRSilvaEJNLMarquesD, et al. Evaluation of design, metallurgy, microhardness, and mechanical properties of glide path instruments: a multimethod approach. J Endod2021; 47: 1917–1923.
20.
TürkyılmazAÇetinE. Endodontide blue-wire ve gold-wire teknolojisi ile üretilen yeni nesil nikel-titanyum eğeler. Necmettin Erbakan Univ Dis Hekim Derg2019; 4: 30–37.
21.
AriHErdemirABelliS. Evaluation of the effect of endodontic irrigation solutions on the microhardness and the roughness of root canal dentin. J Endod2004; 30: 792–795.
22.
ShenYCoilJMZhouHM, et al. ProFile Vortex instruments after clinical use: a metallurgical properties study. J Endod2012; 38: 1613–1617.
23.
NazsızNDumaniAYoldaşO, et al. EDTA-jel’in Reciproc eğenin döngüsel yorgunluk direnci üzerindeki etkisinin değerlendirilmesi: metodolojik çalışma. Turk Klin J Dent Sci2024; 30: 1–7.
24.
SilvaEJNLPradoMCSoaresDN, et al. The effect of ozone therapy in root canal disinfection: a systematic review. Int Endod J2020; 53: 317–332.
25.
AzarpazhoohALimebackH. The application of ozone in dentistry: a systematic review of literature. J Dent2008; 36: 104–116.
26.
FaulFErdfelderEBuchnerA, et al. Statistical power analyses using G*Power 3.1: tests for correlation and regression analyses. Behav Res Methods2009; 41: 1149–1160.
27.
TürkTKeskinCÇetinD, et al. Multimethod assessment of design, mechanical and metallurgical characteristics of ProTaper ultimate, TruNatomy glider, ProGlider, HyFlex EDM and WaveOne Gold Glider glide path instruments. Odontology2025; 113: 1–12.
28.
ASTM International. ASTM E384-17: Standard test method for microindentation hardness of materials. WestConshohocken, PA: ASTM International, 2017.
29.
LuoQKitchenM. Microhardness, indentation size effect and real hardness of plastically deformed austenitic Hadfield steel. Materials2023; 16: 1117.
30.
MartinsJNRSilvaEJNLMarquesD, et al. Design, metallurgical features, and mechanical behaviour of NiTi endodontic instruments from five different heat-treated rotary systems. Materials2022; 15: 1009.
31.
AslantasEEBuzogluHDAltundasarE, et al. Effect of EDTA, sodium hypochlorite, and chlorhexidine gluconate with or without surface modifiers on dentin microhardness. J Endod2014; 40: 876–879.
32.
ZinelisSEliadesTEliadesG. A metallurgical characterization of ten endodontic Ni-Ti instruments: assessing the clinical relevance of shape memory and superelastic properties of Ni-Ti endodontic instruments. Int Endod J2010; 43: 125–134.
33.
HaJHKimSKCohencaN, et al. Effect of R-phase heat treatment on torsional resistance and cyclic fatigue fracture. J Endod2013; 39: 389–393.
34.
UstaSNEymirliA. Comparison of the cyclic fatigue resistance of four different file systems at body temperature. Turk Endod J2022; 7: 69–73.
35.
SurmeKAkmanHÖzkanHB, et al. Comparison of cyclic fatigue resistance of four pediatric rotary file systems at body temperature: an in vitro study. BMC Oral Health2024; 24: 992.
36.
KeskinCInanUDemiralM, et al. Cyclic fatigue resistance of reciproc blue, reciproc, and WaveOne gold reciprocating instruments. J Endod2017; 43: 1360–1363.
37.
KlymusMEAlcaldeMPVivanRR, et al. Effect of temperature on the cyclic fatigue resistance of thermally treated reciprocating instruments. Clin Oral Investig2019; 23: 3047–3052.
38.
HouXMYangYJQianJ. Phase transformation behaviors and mechanical properties of NiTi endodontic files after gold heat treatment and blue heat treatment. J Oral Sci2020; 63: 8–13.
39.
TokerSMOrhanEOBeklenA. Nickel ion release and surface analyses on instrument fragments fractured beyond the apex: a laboratory investigation. BMC Oral Health2023; 23: 703.
40.
GüneçHGKeskinNBHaznedaroğluF. Comparison of cyclic fatigue resistance of different and novel heat-treated nickel-titanium rotary file systems at the intracanal temperature. Int Dent Res2021; 11: 158–164.
41.
AydınUÖzdemirMÇulhaE, et al. Evaluation of cyclic fatigue resistance of novel replica-like instruments in static test model. Appl Bionics Biomech2024; 2024: 8842478.
42.
ArmaganSHaznedarogluF. Scanning electron microscopy analysis of conventional and controlled-memory nickel titanium files before and after multi-uses in root canals. Microsc Res Tech2021; 84: 1321–1327.
43.
AhmedRChoudhryZQaziFUR, et al. Influence of 17% EDTA and Sapindus mukorossi on the surface property of ProTaper Gold rotary endodontic instruments. Appl Sci2022; 12: 7208.
44.
SilvaEJNLMartinsJNRAlcaldeMP, et al. Assessing the fatigue resistance of NiTi instruments: a DSC-based approach to understanding temperature effects. Int Endod J2025; 58: 1267–1276.
45.
AmetranoGD’AntòVDi CaprioMP, et al. Effects of sodium hypochlorite and ethylenediaminetetraacetic acid on rotary nickel-titanium instruments evaluated using atomic force microscopy. Int Endod J2011; 44: 203–209.
46.
ErikCEÖzyürekT. Effects of etidronate, NaOCl, EDTA irrigation solutions and their combinations on cyclic fatigue resistance of nickel-titanium single-file rotary and reciprocating instruments at body temperature. Odontology2019; 107: 190–195.
47.
AlfawazHAlqedairiAAlhamdanM, et al. Effect of NaOCl and EDTA irrigating solutions on the cyclic fatigue resistance of EdgeTaper platinum instruments. BMC Oral Health2022; 22: 195.
48.
LinJKarabucakBLeeS. Effect of sodium hypochlorite on conventional and heat-treated nickel-titanium endodontic rotary instruments: an in vitro study. J Dent Sci2021; 16: 738–743.
49.
RamosMArangurenJMalviciniG, et al. Temperature-dependent effects on cyclic fatigue resistance in three reciprocating endodontic systems: an in vitro study. Materials2025; 18: 952.
50.
ErkalDErK. Causes and prevention of endodontic file fractures: a review of the literature. Acta Stomatol Marisiensis2024; 7: 33–52.
51.
BeruttiEAngeliniERigoloneM, et al. Influence of sodium hypochlorite on fracture properties and corrosion of ProTaper rotary instruments. Int Endod J2006; 39: 693–699.
52.
PetersOABarbakowF. Dynamic torque and apical forces of ProFile.04 rotary instruments during preparation of curved canals. Int Endod J2002; 35: 379–389.
53.
De OliveiraESouzaJOliveiraG. Effect of ozone and 10% sodium ascorbate on human dentin microhardness. RSBO2021; 17: 92–96.
54.
CelibertiPPazeraPLussiA. The impact of ozone treatment on enamel physical properties. Am J Dent2006; 19: 67–72.
55.
FloareADFochtDHajduAI, et al. Ozone and microstructural morphological changes of tooth enamel. Rom J Morphol Embryol2022; 63: 539–544.
56.
El MeligyOAElemamNMTalaatIM. Ozone therapy in medicine and dentistry: a review of the literature. Dent J2023; 11: 187.
