Article: Dynamic torsional resistance of nickel-titanium rotary instruments

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TitleDynamic torsional resistance of nickel-titanium rotary instruments
AuthorsPark, SY2
Cheung, GSP1
Yum, J2
Hur, B2
Park, JK2
Kim, HC2
KeywordsMachining groove
nickel-titanium rotary file
repetitive load
shear fracture
torsional resistance
Twisted File
Issue Date2010
PublisherElsevier Inc. The Journal's web site is located at http://www.jendodon.com
CitationJournal Of Endodontics, 2010, v. 36 n. 7, p. 1200-1204 [How to Cite?]
DOI: http://dx.doi.org/10.1016/j.joen.2010.02.016
AbstractIntroduction: The cyclic fatigue of nickel-titanium (NiTi) rotary instruments has been studied extensively, but there is little information available on torsional fracture. Moreover, a clinical repeated locking effect was not considered in previous studies that evaluated torsional resistance of NiTi instruments. Thus, this study was aimed to compare the repetitive torsional resistance of various NiTi instruments with clinical relevance. Materials and Methods: Five brands of NiTi rotary instruments were selected: Twisted File (TF; SybronEndo, Orange, CA) and RaCe systems (FKG Dentaire, La Chaux-de-Fonds, Switzerland), both with an equilateral triangular cross-section, and the ProTaper (Dentsply Maillefer, Ballaignes, Switzerland), Helix (DiaDent, Chongju, Korea), and FlexMaster (VDW, Munchen, Germany), which had a convex triangular cross-section. Five millimeters of the tip of each file was embedded in composite resin block, and uniform torsional stresses (300 rpm, 1.0 N.cm) were applied repetitively by an endodontic motor with auto-stop mode until the file succumbed to torsional failure. The number of load applications leading to fracture was recorded. All fracture surfaces were examined under the SEM. Results were analyzed nonparametrically with α = 0.05. Results: Under the mode of load applications in this study, TF had the lowest and FlexMaster the highest torsional resistance among the groups (p < 0.05). Scanning electron microscopy examination revealed a typical pattern of torsional fracture for TF, RaCe, and ProTaper that was characterized by circular abrasion marks and skewed dimples near the center of rotation. In addition to these marks, Helix and FlexMaster presented a rough, torn-off appearance. Conclusion: It was concluded that files of same cross-sectional design may exhibit different resistance to fracture probably as a result of the manufacturing process. © 2010 American Association of Endodontists.
ISSN0099-2399
2011 Impact Factor: 2.88
2011 SCImago Journal Rankings: 0.119
DOIhttp://dx.doi.org/10.1016/j.joen.2010.02.016
ISI Accession Number IDWOS:000279802000018
ReferencesReferences in Scopus
DC Field
Value
dc.contributor.authorPark, SY
dc.contributor.authorCheung, GSP
dc.contributor.authorYum, J
dc.contributor.authorHur, B
dc.contributor.authorPark, JK
dc.contributor.authorKim, HC
dc.date.accessioned2010-12-23T08:32:05Z
dc.date.available2010-12-23T08:32:05Z
dc.date.issued2010
dc.description.abstractIntroduction: The cyclic fatigue of nickel-titanium (NiTi) rotary instruments has been studied extensively, but there is little information available on torsional fracture. Moreover, a clinical repeated locking effect was not considered in previous studies that evaluated torsional resistance of NiTi instruments. Thus, this study was aimed to compare the repetitive torsional resistance of various NiTi instruments with clinical relevance. Materials and Methods: Five brands of NiTi rotary instruments were selected: Twisted File (TF; SybronEndo, Orange, CA) and RaCe systems (FKG Dentaire, La Chaux-de-Fonds, Switzerland), both with an equilateral triangular cross-section, and the ProTaper (Dentsply Maillefer, Ballaignes, Switzerland), Helix (DiaDent, Chongju, Korea), and FlexMaster (VDW, Munchen, Germany), which had a convex triangular cross-section. Five millimeters of the tip of each file was embedded in composite resin block, and uniform torsional stresses (300 rpm, 1.0 N.cm) were applied repetitively by an endodontic motor with auto-stop mode until the file succumbed to torsional failure. The number of load applications leading to fracture was recorded. All fracture surfaces were examined under the SEM. Results were analyzed nonparametrically with α = 0.05. Results: Under the mode of load applications in this study, TF had the lowest and FlexMaster the highest torsional resistance among the groups (p < 0.05). Scanning electron microscopy examination revealed a typical pattern of torsional fracture for TF, RaCe, and ProTaper that was characterized by circular abrasion marks and skewed dimples near the center of rotation. In addition to these marks, Helix and FlexMaster presented a rough, torn-off appearance. Conclusion: It was concluded that files of same cross-sectional design may exhibit different resistance to fracture probably as a result of the manufacturing process. © 2010 American Association of Endodontists.
dc.description.natureLink_to_subscribed_fulltext
dc.identifier.citationJournal Of Endodontics, 2010, v. 36 n. 7, p. 1200-1204 [How to Cite?]
DOI: http://dx.doi.org/10.1016/j.joen.2010.02.016
dc.identifier.doihttp://dx.doi.org/10.1016/j.joen.2010.02.016
dc.identifier.epage1204
dc.identifier.hkuros177053
dc.identifier.isiWOS:000279802000018
dc.identifier.issn0099-2399
2011 Impact Factor: 2.88
2011 SCImago Journal Rankings: 0.119
dc.identifier.issue7
dc.identifier.openurl
dc.identifier.pmid20630299
dc.identifier.scopuseid_2-s2.0-78049264432
dc.identifier.spage1200
dc.identifier.urihttp://hdl.handle.net/10722/129073
dc.identifier.volume36
dc.languageeng
dc.publisherElsevier Inc. The Journal's web site is located at http://www.jendodon.com
dc.publisher.placeUnited States
dc.relation.ispartofJournal of Endodontics
dc.relation.referencesReferences in Scopus
dc.subjectMachining groove
dc.subjectnickel-titanium rotary file
dc.subjectrepetitive load
dc.subjectshear fracture
dc.subjecttorsional resistance
dc.subjectTwisted File
dc.titleDynamic torsional resistance of nickel-titanium rotary instruments
dc.typeArticle
Author Affiliations
  1. The University of Hong Kong
  2. Pusan National University