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Article: Defects in ProTaper S1 instruments after clinical use: Fractographic examination

TitleDefects in ProTaper S1 instruments after clinical use: Fractographic examination
Authors
KeywordsFatigue
Fracture
Nickel-titanium
Rotary instrument
Shear
Issue Date2005
PublisherBlackwell Publishing Ltd. The Journal's web site is located at http://www.blackwellpublishing.com/journals/IEJ
Citation
International Endodontic Journal, 2005, v. 38 n. 11, p. 802-809 How to Cite?
AbstractAim: To investigate the mode of failure of a brand of nickel-titanium instruments separated during clinical use, by detailed examination of the fracture surface. Methodology: A total of 122 ProTaper S1 instruments were discarded from an endodontic clinic at a stomatological school in China over a period of 17 months; 28 had fractured. These fractured instruments were ultrasonically cleaned, autoclaved and then examined under a scanning electron microscope. From the lateral view the fracture was classified into 'torsional' or 'flexural'. The specimens were then re-mounted and the presence of characteristics of shear failure and fatigue striations was recorded under high-power view of the fracture surface. The difference in the mean lengths of fractured segment between the shear and fatigue groups was compared using Student's t-test. Results: Twenty-seven separated instruments were available for analysis. Under low-power magnification, only two fell into the category of 'torsional' failure when examined laterally; the others appeared to be 'flexural'. Close examination of the fracture surface revealed the presence of fatigue striations in 18 specimens. Nine instruments (including the two putative 'torsional' failures above) fell into the shear fracture group, in which fatigue striations were absent or characteristics of shear failure of the material were found. The mean length of fractured segments resulting from fatigue failure (4.3 ± 1.9 mm) was significantly greater than that for shear failure (2.5 ± 0.8 mm) (P < 0.001, two-sample t-test). Conclusions: Examination of the fracture surface at high magnification is essential to reveal features that may indicate the possible origin of cracks and the mode of material failure. Macroscopic or lateral examination of separated instruments would fail to reveal the true mechanism of failure. Fatigue seems to be an important reason for the separation of rotary instruments during clinical use. © 2005 International Endodontic Journal.
Persistent Identifierhttp://hdl.handle.net/10722/65902
ISSN
2015 Impact Factor: 2.842
2015 SCImago Journal Rankings: 2.020
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorCheung, GSPen_HK
dc.contributor.authorPeng, Ben_HK
dc.contributor.authorBian, Zen_HK
dc.contributor.authorShen, Yen_HK
dc.contributor.authorDarvell, BWen_HK
dc.date.accessioned2010-09-06T05:41:57Z-
dc.date.available2010-09-06T05:41:57Z-
dc.date.issued2005en_HK
dc.identifier.citationInternational Endodontic Journal, 2005, v. 38 n. 11, p. 802-809en_HK
dc.identifier.issn0143-2885en_HK
dc.identifier.urihttp://hdl.handle.net/10722/65902-
dc.description.abstractAim: To investigate the mode of failure of a brand of nickel-titanium instruments separated during clinical use, by detailed examination of the fracture surface. Methodology: A total of 122 ProTaper S1 instruments were discarded from an endodontic clinic at a stomatological school in China over a period of 17 months; 28 had fractured. These fractured instruments were ultrasonically cleaned, autoclaved and then examined under a scanning electron microscope. From the lateral view the fracture was classified into 'torsional' or 'flexural'. The specimens were then re-mounted and the presence of characteristics of shear failure and fatigue striations was recorded under high-power view of the fracture surface. The difference in the mean lengths of fractured segment between the shear and fatigue groups was compared using Student's t-test. Results: Twenty-seven separated instruments were available for analysis. Under low-power magnification, only two fell into the category of 'torsional' failure when examined laterally; the others appeared to be 'flexural'. Close examination of the fracture surface revealed the presence of fatigue striations in 18 specimens. Nine instruments (including the two putative 'torsional' failures above) fell into the shear fracture group, in which fatigue striations were absent or characteristics of shear failure of the material were found. The mean length of fractured segments resulting from fatigue failure (4.3 ± 1.9 mm) was significantly greater than that for shear failure (2.5 ± 0.8 mm) (P < 0.001, two-sample t-test). Conclusions: Examination of the fracture surface at high magnification is essential to reveal features that may indicate the possible origin of cracks and the mode of material failure. Macroscopic or lateral examination of separated instruments would fail to reveal the true mechanism of failure. Fatigue seems to be an important reason for the separation of rotary instruments during clinical use. © 2005 International Endodontic Journal.en_HK
dc.languageengen_HK
dc.publisherBlackwell Publishing Ltd. The Journal's web site is located at http://www.blackwellpublishing.com/journals/IEJen_HK
dc.relation.ispartofInternational Endodontic Journalen_HK
dc.rightsInternational Endodontic Journal. Copyright © Blackwell Publishing Ltd.en_HK
dc.subjectFatigueen_HK
dc.subjectFractureen_HK
dc.subjectNickel-titaniumen_HK
dc.subjectRotary instrumenten_HK
dc.subjectShearen_HK
dc.subject.meshDental Alloys - chemistryen_HK
dc.subject.meshEquipment Designen_HK
dc.subject.meshEquipment Failureen_HK
dc.subject.meshHumansen_HK
dc.subject.meshMaterials Testingen_HK
dc.subject.meshMicroscopy, Electron, Scanningen_HK
dc.subject.meshNickel - chemistryen_HK
dc.subject.meshPliabilityen_HK
dc.subject.meshRoot Canal Preparation - instrumentationen_HK
dc.subject.meshRotationen_HK
dc.subject.meshStress, Mechanicalen_HK
dc.subject.meshSurface Propertiesen_HK
dc.subject.meshTitanium - chemistryen_HK
dc.titleDefects in ProTaper S1 instruments after clinical use: Fractographic examinationen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0143-2885&volume=38&spage=802&epage=809&date=2005&atitle=Defects+in+ProTaper+S1+instruments+after+clinical+use:+fractographic+examinationen_HK
dc.identifier.emailCheung, GSP: spcheung@hkucc.hku.hken_HK
dc.identifier.emailDarvell, BW: b.w.darvell@hku.hken_HK
dc.identifier.authorityCheung, GSP=rp00016en_HK
dc.identifier.authorityDarvell, BW=rp00007en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1111/j.1365-2591.2005.01020.xen_HK
dc.identifier.pmid16218972-
dc.identifier.scopuseid_2-s2.0-22544438540en_HK
dc.identifier.hkuros115931en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-22544438540&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume38en_HK
dc.identifier.issue11en_HK
dc.identifier.spage802en_HK
dc.identifier.epage809en_HK
dc.identifier.isiWOS:000232493100005-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridCheung, GSP=7005809531en_HK
dc.identifier.scopusauthoridPeng, B=7102873002en_HK
dc.identifier.scopusauthoridBian, Z=7103314705en_HK
dc.identifier.scopusauthoridShen, Y=7404767171en_HK
dc.identifier.scopusauthoridDarvell, BW=7005953926en_HK
dc.identifier.citeulike348621-

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