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Fractographic 분석을 통한 HEROShaper 니켈티타늄 전동 파일의 피로파절에 미치는 표면결함의 역할

Other Titles
 The Effect of Surface Defects on the Cyclic Fatigue Fracture of HEROShaper Ni-Ti rotary files in a Dynamic Model : A Fractographic Analysis 
Authors
 Jung-Kyu Lee  ;  Eui-Sung Kim  ;  Kee-Yeon Kum  ;  Myoung-Whai Kang 
Citation
 Journal of Korean Academy of Operative Dentistry (대한치과보존학회지), Vol.32(2) : 130-137, 2007 
Journal Title
Journal of Korean Academy of Operative Dentistry(대한치과보존학회지)
ISSN
 1225-0864 
Issue Date
2007
Abstract
This in vitro study examined the effect of surface defects on cutting blades on the extent of the cyclic fatigue fracture of HEROShaper Ni-Ti rotary files using fractographic analysis of the fractured surfaces. A total of 45 HEROShaper (MicroMega) Ni-Ti rotary flies with a #30/.04 taper were divided into three groups of 15 each. Group 1 contained new HEROShapers without any surface defects. Group 2 contained HEROShapers with manufacturing defects such as metal rollover and machining marks. Croup 3 contained HEROShapers that had been clinically used for the canal preparation of 4-6 molars A fatigue-testing device was designed to allow cyclic tension and compressive stress on the tip of the instrument whilst maintaining similar conditions to those experienced in a clinic. The level of fatigue fracture time was measured using a computer connected the system. Statistical analysis was performed using a Tukey's test. Scanning electron microscopy (SEM) was used for fractographic analysis of the fractured surfaces. The fatigue fracture time between groups 1 and 2, and between groups 1 and 3 was significantly different (p<0.05) but there was no significant difference between groups 2 and 3 (p>0.05). A low magnification SEM views show brittle fracture as the main initial failure mode At higher magnification, the brittle fracture region showed clusters of fatigue striations and a large number of secondary cracks. These fractures typically led to a central region of catastrophic ductile failure. Qualitatively, the ductile fracture region was characterized by the formation of microvoids and dimpling. The fractured surfaces of the HEROShapers in groups 2 and 3 were always associated with pre-existing surface defects.
Files in This Item:
T200701064.pdf Download
DOI
10.5395/JKACD.2007.32.2.130
Appears in Collections:
2. College of Dentistry (치과대학) > Dept. of Conservative Dentistry (보존과학교실) > 1. Journal Papers
Yonsei Authors
Kum, Kee Yeon(금기연)
Kim, Eui Seong(김의성) ORCID logo https://orcid.org/0000-0003-2126-4761
URI
https://ir.ymlib.yonsei.ac.kr/handle/22282913/96360
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