Cleaning and Shaping Ability of Gentlefile, HyFlex EDM, and ProTaper Next Instruments: A Combined Micro–computed Tomographic and Scanning Electron Microscopic Study

Htun, Pyae Hein; Ebihara, Arata; Maki, Keiichiro; Kimura, Shunsuke; Nishijo, Miki; Okiji, Takashi

doi:10.1016/j.joen.2020.03.027

Cited by 15 publications

(11 citation statements)

References 32 publications

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“…To overcome morphological variations and establish a reliable baseline and comparability of the groups, the teeth used in this study were anatomically matched in terms of pre‐operative geometric parameters (Bürklein et al ., 2014). The canal morphology was determined by micro‐CT imaging, a nondestructive and reproducible method for three‐dimensional assessment of the root canal preparation (De‐Deus et al ., 2019, Htun et al ., 2020a).…”

Section: Discussionmentioning

confidence: 99%

Influence of rotational speed on torque/force generation and shaping ability during root canal instrumentation of extracted teeth with continuous rotation and optimum torque reverse motion

et al. 2021

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Aim To evaluate how different rotational speeds affect the torque/force generation and shaping ability of rotary root canal instrumentation using JIZAI (MANI, Utsunomiya, Japan) nickel‐titanium instruments in continuous rotation and optimum torque reverse (OTR) motion. Methodology Mesial root canals of extracted mandibular molars were instrumented up to size 25, 0.04 taper using JIZAI instruments, and anatomically matched canals were selected based on geometric features of the canal [canal volume (mm3), surface area (mm2), length, 15°–20° curvature and radius of curvature (4–8 mm)] after micro‐computed tomographic scanning. An automated root canal instrumentation and torque/force analysing device was programmed to permit a simulated pecking motion (2 s downward and 1 s upward at 50 mm min−1). The selected canals were prepared with size 25, 0.06 taper JIZAI instruments using continuous rotation or OTR motion and further subdivided according to the rotational speed (300 or 500 rpm, n = 10 each). Real‐time clockwise/counterclockwise torque and downward/upward force were recorded using a custom‐made torque/force analysing device. Then, the registered pre‐ and post‐operative micro‐computed tomographic datasets were examined to evaluate the canal volume changes and centring ratios at 1, 3, 5 and 7 mm from the apical foramen. Data were analysed using two‐way analysis of variance or the Kruskal–Wallis test and Mann–Whitney U test with Bonferroni correction (α = 5%). Results Maximum upward force and clockwise torque were significantly smaller in 500 rpm groups than in 300 rpm groups (P < .05); however, no significant difference was found between continuous rotation and OTR motion (P > .05). OTR motion developed higher maximum counterclockwise torque than continuous rotation (P < .05). Maximum downward force, canal volume changes and centring ratios were not significantly different among all groups (P > .05). There was no file fracture in any of the groups. Conclusions Under laboratory conditions using JIZAI instruments, a rotational speed of 500 rpm generated significantly lower maximum screw‐in forces and torque values than rotational speed of 300 rpm. Continuous rotation and OTR motion performed similarly in shaping the canals.

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Section: Discussionmentioning

confidence: 99%

Influence of rotational speed on torque/force generation and shaping ability during root canal instrumentation of extracted teeth with continuous rotation and optimum torque reverse motion

et al. 2021

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“…In fact, during the evaluation of the performance of NiTi rotary instruments the shaping ability should be considered. As stated by several Authors, the shaping ability could be considered as a macro-group of characteristics that comprises centering ability, canal transportation, difference between canal volume before and after therapy and the ratio between touched an untouched dentinal area [ 90 , 91 , 92 , 93 , 94 , 95 ].…”

Section: Introductionmentioning

confidence: 99%

“…The two main popular and thoroughly validated methods used to evaluate these factors are the Micro-Computed Tomography (CT) and the SEM analysis, singularly used or in combination, that allow a precise calculation of the interested measurement trough the aid of digital software [ 90 , 92 ]. In our opinion Micro-CT imaging should be preferred because it is non-destructive 3-dimensional analysis and gives high-resolution images to precisely evaluate the untouched area, volume changes, and transportation in comparison to SEM analysis that requires the split of the teeth [ 90 ].…”

Section: Introductionmentioning

confidence: 99%

An Update on Nickel-Titanium Rotary Instruments in Endodontics: Mechanical Characteristics, Testing and Future Perspective—An Overview

et al. 2021

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Since the introduction of Nickel-Titanium alloy as the material of choice for the manufacturing of endodontic rotary instruments, the success rate of the root canal therapies has been significantly increased. This success mainly arises from the properties of the Nickel-Titanium alloy: the biocompatibility, the superelasticity and the shape memory effect. Those characteristics have led to a reduction in time of endodontic treatments, a simplification of instrumentation procedures and an increase of predictability and effectiveness of endodontic treatments. Nevertheless, the intracanal separation of Nickel-Titanium rotary instruments is still a major concern of endodontists, with a consequent possible reduction in the outcome rate. As thoroughly demonstrated, the two main causes of intracanal separation of endodontic instruments are the cyclic fatigue and the torsional loads. As results, in order to reduce the percentage of intracanal separation research and manufacturers have been focused on the parameters that directly or indirectly influence mechanical properties of endodontic rotary instruments. This review describes the current state of the art regarding the Nickel-Titanium alloy in endodontics, the mechanical behavior of endodontic rotary instruments and the relative stresses acting on them during intracanal instrumentation, highlighting the limitation of the current literature.

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“…However, several of the recent studies [9,12] indicated that, as a unique rotary system made from SS, GF was more exible and prepared better for oval root canals than some of the NiTi instruments, and our study showed the GF system was also more centered and less transported than PT in the middle and apical sections of the narrow and curved root canals. This nding is consistent with that of Moreinos [9] who reported that GF les created less vertical force on bent canals.…”

Section: Discussionmentioning

confidence: 51%

“…High-speed rotation in uences the intracanal uid dynamics and increases effective irrigation [11]. GF instruments have been reported [12] to have great shaping and cleaning ability in oval canals, but that in the severely curved simulated canals is still lacking.…”

Section: Introductionmentioning

confidence: 99%

Gentlefile Versus Protaper in the Shaping Ability in Simulated J-shaped Root Canals

Chen

2021

Preprint

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Background: The aim of this study was to compare the shaping ability of Gentlefile (GF), a unique stainless-steel (SS) rotary system, and ProTaper (PT), a popular mechanical nickel-titanium (NiTi) system, in J-shaped simulated canals. Methods: Thirty-three resin blocks with a J-shaped canal were selected and randomly divided into 3 groups according to tip diameters: GF red (#23); PT F2(#25); GF blue (#26). They were prepared in one training model which imitated human dentition. Specimens were photographed by a dental operating microscope before and after preparation. The images were processed and measured using professional software. Centering ability and canal transportation were calculated, canal aberration and instrument separation were also recorded. Results: The GF system was significantly less transported than PT F2 in the apical and middle section. What’s more, better centering ability of GF was shown in all sections, including the coronal level. However, there was no difference between GF red and GF blue based on above criteria. Two cases of instrument separation of GF were noted.Conclusion: Under the conditions of this study, the two GF files showed better shaping ability, but were more easily separated than PT F2. As a novel SS rotary system, Gentlefile is more flexible to prepare narrow and curved root canals by scraping dentin with high-speed rotation, which might help remove smear layer much thoroughly and cause less dentin microcracks.

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Cleaning and Shaping Ability of Gentlefile, HyFlex EDM, and ProTaper Next Instruments: A Combined Micro–computed Tomographic and Scanning Electron Microscopic Study

Cited by 15 publications

References 32 publications

Influence of rotational speed on torque/force generation and shaping ability during root canal instrumentation of extracted teeth with continuous rotation and optimum torque reverse motion

Influence of rotational speed on torque/force generation and shaping ability during root canal instrumentation of extracted teeth with continuous rotation and optimum torque reverse motion

An Update on Nickel-Titanium Rotary Instruments in Endodontics: Mechanical Characteristics, Testing and Future Perspective—An Overview

Gentlefile Versus Protaper in the Shaping Ability in Simulated J-shaped Root Canals

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