How Hedstrom files fail during clinical use? A retrieval study based on SEM, optical microscopy and micro-XCT analysis

Spiros Zinelis; Youssef S. Al Jabbari

doi:10.1515/bmt-2017-0182

Article

How Hedstrom files fail during clinical use? A retrieval study based on SEM, optical microscopy and micro-XCT analysis

Spiros Zinelis and Youssef S. Al Jabbari

Published/Copyright: May 1, 2018

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From the journal Biomedical Engineering / Biomedizinische Technik Volume 64 Issue 2

Abstract

This study was conducted to evaluate the failure mechanism of clinically failed Hedstrom (H)-files. Discarded H-files (n=160) from #8 to #40 ISO sizes were collected from different dental clinics. Retrieved files were classified according to their macroscopic appearance and they were investigated under scanning electron microscopy (SEM) and X-ray micro-computed tomography (mXCT). Then the files were embedded in resin along their longitudinal axis and after metallographic grinding and polishing, studied under an incident light microscope. The macroscopic evaluation showed that small ISO sizes (#08–#15) failed by extensive plastic deformation, while larger sizes (≥#20) tended to fracture. Light microscopy and mXCT results coincided showing that unused and plastically deformed files were free of internal defects, while fractured files demonstrate the presence of intense cracking in the flute region. SEM analysis revealed the presence of striations attributed to the fatigue mechanism. Secondary cracks were also identified by optical microscopy and their distribution was correlated to fatigue under bending loading. Experimental results demonstrated that while overloading of cutting instruments is the predominating failure mechanism of small file sizes (#08–#15), fatigue should be considered the fracture mechanism for larger sizes (≥#20).

Keywords: endodontic; fractography; Hedstrom; micro-XCT; retrieval analysis; SEM

Corresponding author: Spiros Zinelis, Associate Professor, Department of Biomaterials, School of Dentistry, National and Kapodistrian University of Athens, Thivon 2, Goudi, 11527 Athens, Greece; and Dental Biomaterials Research and Development Chair, King Saud University, Riyadh, Saudi Arabia, Phone: +302107461102, Fax: +302107461306

Acknowledgments

The authors extend their appreciation to the International Scientific Partnership Program (ISPP) at King Saud University for funding this research work through ISPP# 0060.

Author Statement
Research funding: Authors state no funding involved.
Conflict of interest: Authors state no conflict of interest.
Informed consent: Informed consent is not applicable.
Ethical approval: The conducted research is not related to either human or animals use.

References

[1] McGuigan MB, Louca C, Duncan HF. Clinical decision-making after endodontic instrument fracture. Br Dent J 2013;214:395–400.10.1038/sj.bdj.2013.379Search in Google Scholar

[2] McGuigan MB, Louca C, Duncan HF. Endodontic instrument fracture: causes and prevention. Br Dent J 2013;214:341–8.10.1038/sj.bdj.2013.324Search in Google Scholar

[3] Cheung GSP. Instrument fracture: mechanisms, removal of fragments, and clinical outcomes. Endod Topics 2007;16:1–26.10.1111/j.1601-1546.2009.00239.xSearch in Google Scholar

[4] Parashos P, Messer HH. Rotary NiTi instrument fracture and its consequences. J Endod 2006;32:1031–43.10.1016/j.joen.2006.06.008Search in Google Scholar

[5] Al-Fouzan KS. Incidence of rotary ProFile instrument fracture and the potential for bypassing in vivo. Int Endod J 2003;36:864–67.10.1111/j.1365-2591.2003.00733.xSearch in Google Scholar

[6] Bergenholtz G, Lekholm U, Milthon R, Heden G, Odesjo B, Engstrom B. Retreatment of endodontic fillings. Scand J Dent Res 1979;87:217–24.10.1111/j.1600-0722.1979.tb00675.xSearch in Google Scholar

[7] Crump MC, Natkin E. Relationship of broken root canal instruments to endodontic case prognosis: a clinical investigation. J Am Dent Assoc 1970;80:1341–7.10.14219/jada.archive.1970.0259Search in Google Scholar

[8] Ramirez-Salomon M, Soler-Bientz R, de la Garza-Gonzalez R, Palacios-Garza CM. Incidence of lightspeed separation and the potential for bypassing. J Endod 1997;23:586–7.10.1016/S0099-2399(06)81128-3Search in Google Scholar

[9] Schafer E, Schulz-Bongert U, Tulus G. Comparison of hand stainless steel and nickel titanium rotary instrumentation: a clinical study. J Endod 2004;30:432–5.10.1097/00004770-200406000-00014Search in Google Scholar PubMed

[10] Spili P, Parashos P, Messer HH. The impact of instrument fracture on outcome of endodontic treatment. J Endod 2005;31:845–50.10.1097/01.don.0000164127.62864.7cSearch in Google Scholar PubMed

[11] Miserendino L. Instruments, materials and devices. In: Cohens S, Burns R, editors. Pathways of the Pulp. 5th ed. St Louis, MO: Mosby-Year Book In; 1991:388–432.Search in Google Scholar

[12] Zinelis S, Margelos J. Failure mechanism of Hedstroem endodontic files in vivo. J Endod 2002;28:471–3.10.1097/00004770-200206000-00014Search in Google Scholar

[13] Darabara M, Bourithis L, Zinelis S, Papadimitriou GD. Assessment of elemental composition, microstructure, and hardness of stainless steel endodontic files and reamers. J Endod 2004;30:523–6.10.1097/00004770-200407000-00015Search in Google Scholar

[14] Iqbal MK, Kohli MR, Kim JS. A retrospective clinical study of incidence of root canal instrument separation in an endodontics graduate program: a PennEndo database study. J Endod 2006;32:1048–52.10.1016/j.joen.2006.03.001Search in Google Scholar

[15] Shen Y, Cheung GS, Bian Z, Peng B. Comparison of defects in ProFile and ProTaper systems after clinical use. J Endod 2006;32:61–5.10.1016/j.joen.2005.10.017Search in Google Scholar

[16] Yared GM, Bou Dagher FE, Machtou P. Influence of rotational speed, torque and operator’s proficiency on ProFile failures. Int Endod J 2001;34:47–53.10.1046/j.1365-2591.2001.00352.xSearch in Google Scholar

[17] Yared GM, Dagher FE, Machtou P, Kulkarni GK. Influence of rotational speed, torque and operator proficiency on failure of Greater Taper files. Int Endod J 2002;35:7–12.10.1046/j.1365-2591.2002.00443.xSearch in Google Scholar

[18] Brantley WA, Luebke NH, Luebke FL, Mitchell JC. Performance of engine-driven rotary endodontic instruments with a superimposed bending deflection: V. Gates Glidden and Peeso drills. J Endod 1994;20:241–5.10.1016/S0099-2399(06)80286-4Search in Google Scholar

[19] Luebke NH, Brantley WA. Torsional and metallurgical properties of rotary endodontic instruments. 2. Stainless steel Gates Glidden drills. J Endod 1991;17:319–23.10.1016/S0099-2399(06)81699-7Search in Google Scholar

[20] Luebke NH, Brantley WA, Sabri ZI, Luebke FL, Lausten LL. Physical dimensions, torsional performance, bending properties, and metallurgical characteristics of rotary endodontic instruments. VI. Canal Master drills. J Endod 1995;21:259–63.10.1016/S0099-2399(06)80993-3Search in Google Scholar

[21] Kosti E, Zinelis S, Lambrianidis T, Margelos J. A comparative study of crack development in stainless-steel Hedstrom files used with step-back or crown-down techniques. J Endod 2004;30:38–41.10.1097/00004770-200401000-00008Search in Google Scholar PubMed

[22] Tepel J, Schafer E. Endodontic hand instruments: cutting efficiency, instrumentation of curved canals, bending and torsional properties. Endod Dent Traumatol 1997;13:201–10.10.1111/j.1600-9657.1997.tb00041.xSearch in Google Scholar

[23] Tepel J, Schafer E, Hoppe W. Properties of endodontic hand instruments used in rotary motion. Part 3. Resistance to bending and fracture. J Endod 1997;23:141–5.10.1016/S0099-2399(97)80262-2Search in Google Scholar

Received: 2017-08-19

Accepted: 2018-03-22

Published Online: 2018-05-01

Published in Print: 2019-04-24

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Articles in the same Issue

https://doi.org/10.1515/bmt-2017-0182

Keywords for this article

endodontic; fractography; Hedstrom; micro-XCT; retrieval analysis; SEM