Dynamic Torsional and Cyclic Fracture Behavior of ProFile Rotary Instruments at Continuous or Reciprocating Rotation as Visualized with High-speed Digital Video Imaging

Tokita, Daisuke; Ebihara, Arata; Miyara, Kana; Okiji, Takashi

doi:10.1016/j.joen.2017.03.024

Cited by 30 publications

(31 citation statements)

References 31 publications

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“…5). This is consistent with previous studies showing that reciprocation induces slower crack propagation than continuous rotation 34) , and that cyclic fatigue resistance of CM wire instruments increases with reciprocation 35) .…”

Section: Discussionsupporting

confidence: 93%

Evaluation of selected mechanical properties of NiTi rotary glide path files manufactured from controlled memory wires

Nishijo

Ebihara

Tokita

et al. 2018

Dental Materials Journal

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This study aimed to investigate mechanical properties related to flexibility and fracture resistance of controlled memory wiremanufactured nickel-titanium rotary glide path files [HyFlex EDM Glide Path File (EDM) and HyFlex GPF (GPF)]. Scout RaCe (RaCe) served as control. Bending loads, torsional/cyclic fatigue resistance, and screw-in forces were measured. EDM showed a significantly larger torque at fracture, a longer time to cyclic fracture in reciprocation and a larger screw-in force compared with GPF and RaCe. GPF showed significantly lower bending loads and higher angular deflection values than EDM and RaCe, and a significantly longer time to cyclic fracture than RaCe. The time to cyclic fracture was significantly longer in reciprocation compared with continuous rotation in EDM and GPF. It can be concluded that EDM and/or GPF showed higher flexibility and cyclic/torsional fatigue resistance compared with RaCe; and that reciprocation conferred better cyclic fatigue resistance to EDM and GPF.

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Section: Discussionsupporting

confidence: 93%

Evaluation of selected mechanical properties of NiTi rotary glide path files manufactured from controlled memory wires

Nishijo

Ebihara

Tokita

et al. 2018

Dental Materials Journal

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“…Regarding instrument distortions, surface wear and fracture, no statistical differences were found between PT F2 and F3 instruments after 1, 3 and 6 uses, regardless the protocol used. Nevertheless, for some instruments, the number of uses increased spiral distortion and surface wear, agreeing with other studies that investigated the occurrence of defects on NiTi rotary instruments after use 10,34,35,36,37,38 .…”

Section: Discussionsupporting

confidence: 89%

Centering ability, canal transportation and surface modifications of ProTaper F2 and F3 used in continuous rotation and reciprocating motion in curved root canals

Andreazza¹,

Santos²,

Pinheiro

et al. 2019

R. Fac. Odontol. Porto Alegre

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Aims: To evaluate the centering ability, canal transportation and surface modifications of F2 and F3 ProTaper Universal (PT) instruments used in continuous rotation (CR) and reciprocating motion (RM) for the preparation of curved root canals. Material and methods: sixty mesiobuccal root canals of upper molars with curvatures between 25º and 35° were divided into three groups: I - PT in CR up to F3; II - PT in RM up to F3; III - F2 and F3 PT instruments in RM. Cone Beam Computed Tomography images were obtained before and after instrumentation. The scans were superimposed to determine the centering ability and canal transportation in apical, medium and cervical thirds. The apical 6 mm of the F2 and F3 files were evaluated under Scanning Electron Microscope before and after 1, 3 and 6 uses to assess distortion, surface wear and fracture. The statistical analysis of centering ability and canal transportation were performed by Kruskal–Wallis and ANOVA, respectively. The scores for deformation and surface wear were compared using ANOVA. Fisher’s exact test was used for the evaluation of instrument fracture. Results: there were no significant differences between groups regarding centering ability and canal transportation, as well as, for distortion, surface wear and fracture (p>.05). Conclusion: F2 and F3 instruments can be used for curved canals instrumentation. However, when used for entire canal preparation, F2 and F3 should be discarded after single use.

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“…Such studies mainly are performed in metal tubes with defined curvatures (angle, length and radius of curvature), filled with a lubricant, thus preventing torsional load, although different study designs also have been developed such as rotation against a plane, three‐point bending tests or block‐and‐rod assemblies (Plotino et al , Shen & Cheung ). In some studies, a 3‐pin model has been used instead of the tube model (Cheung & Darvell ,b, Tokita et al ). A survey on study designs is presented in Table .…”

Section: Modes Of Fracturementioning

confidence: 99%

A critical appraisal of studies on cyclic fatigue resistance of engine‐driven endodontic instruments

Hülsmann

Donnermeyer

Schäfer³

2019

Int Endodontic J

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The endodontic literature contains a plethora of studies on static and dynamic cyclic fatigue resistance tests performed on a large array of rotary or reciprocating nickel–titanium endodontic instruments. It was the aim of this review to summarize the currently available evidence to point out the different outcomes from static versus dynamic tests and to assess whether cyclic fatigue tests provide useful data and information for clinical practice. An electronic literature research in the database PubMed was performed using appropriate search terms, and the titles and abstract were screened for relevance. Language was restricted to English. The review reveals marked differences between the results obtained in static and dynamic tests, and also, the results for the same instruments assessed either under static or dynamic experimental conditions are widely inconsistent. Between the lowest and the highest value for one and the same pathfinding instrument was a factor of about 123 when cyclic fatigue was assessed either under static or dynamic experimental conditions. Moreover, standard deviations of up to 30% have been reported. Environmental temperature has a 500% impact on the lifetime of instruments. In conclusion, fatigue resistance tests conducted under room temperature should be regarded as having little meaning and the scientific and clinical benefits of fatigue resistance tests are very limited. These data should be provided by the manufacturer of the instruments.

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Dynamic Torsional and Cyclic Fracture Behavior of ProFile Rotary Instruments at Continuous or Reciprocating Rotation as Visualized with High-speed Digital Video Imaging

Cited by 30 publications

References 31 publications

Evaluation of selected mechanical properties of NiTi rotary glide path files manufactured from controlled memory wires

Evaluation of selected mechanical properties of NiTi rotary glide path files manufactured from controlled memory wires

Centering ability, canal transportation and surface modifications of ProTaper F2 and F3 used in continuous rotation and reciprocating motion in curved root canals

A critical appraisal of studies on cyclic fatigue resistance of engine‐driven endodontic instruments

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