• Journal of Korean Dental Science
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• 제15권2호
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• pp.112-120
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• 2022

In this article, the contemporary root canal treatment procedure using nickel-titanium (NiTi) instruments was reviewed to understand the correlations between the properties of files and safety of the clinical usage. Literatures were reviewed according to the process of clinical procedure of the root canal preparation, mainly for shaping during orifice flaring, glide-path preparation, and main canal instrumentation. Considering the reasons for NiTi file fracture, clinically implacable issues and ideas were discussed to reduce the fracture risk and increase clinical efficiency of the NiTi file systems. Various kinds of NiTi file systems have their own characteristics and properties given from their geometries and heat treatments and so on. Proper selection and careful usage of the NiTi file systems may reduce the risk of file fracture and increase the efficiency of NiTi file systems. Understanding of the clinical implications from the mechanical properties and characteristics of the engine driven NiTi instruments may decrease the risk of NiTi file fractures and increase the success rate in root canal treatment.

• Restorative Dentistry and Endodontics
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• 제38권2호
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• pp.93-97
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• 2013

During root canal preparation procedures, the potential for instrument breakage is always present. When instrument breakage occurs, it leads to anxiety of the clinician and as well as a metallic obstruction of the canal which hinders further cleaning and shaping. Separated instruments must always be attempted for retrieval and if retrieval is not possible bypass should be tried. With the increased use of nickel-titanium (NiTi) instruments the incidence of separated instruments has increased. A considerable amount of research has been done to understand the various factors related to the fracture of NiTi instruments to minimize its occurrence. This paper presents a review of the literature regarding the fracture of NiTi instruments and also describes a case report showing the use of a modified 18-guage needle and cyanoacrylate glue to retrieve a separated NiTi instrument from the mesiolingual canal of a mandibular first molar.

• Restorative Dentistry and Endodontics
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• 제36권1호
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• pp.1-11
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• 2011

서론: 이 문헌의 목적은 Nickel-titanium (NiTi) 전동 파일의 기계적 형태적 양상과 이에 의한 임상적 연관성을 고찰하는 것이다. NiTi 전동 파일은 다양한 고유의 형태로 시장에 소개되었고 경쟁 상품에 비해서 근관 성형에 더 나은 능력을 가졌다고 주장하고 있다. 본론: 이 문헌에서는 NiTi 전동 파일의 형태(예. 팁, 테이퍼, helical angle 등)와 파일의 임상 적용 성과 사이의 가능한 상관관계를 다음과 같이 다룬다; - NiTi 전동 파일의 파절 양상 - 비활성 파일팁과 glide path - 파일 경사도와 임상 효과 - 파일 횡단면적과 임상 효과 - 열처리와 표면 특성 - Screw-in 효과와 치근 상아질의 유지 - Screw-in 효과를 줄이기 위한 고안 결론: 이상의 내용을 바탕으로, 임상가는 다양한 NiTi 전동 기구를 사용함에 있어 임상 상황에 적절한 장점을 고려하여 선택하고 사용할 수 있는 도움을 받을 수 있을 것이다.

• Restorative Dentistry and Endodontics
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• 제45권2호
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• pp.25.1-25.12
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• 2020

Objectives: This systematic review evaluated the influence of autoclave sterilization procedures on the cyclic fatigue resistance of heat-treated nickel-titanium (NiTi) instruments. Materials and Methods: A systematic search without restrictions was conducted in the following electronic databases: PubMed, Scopus, Web of Science, ScienceDirect, Cochrane, and Open Grey. The hand search was also performed in the main endodontic journals. The eligible studies were submitted to the methodological assessment and data extraction. Results: From 203 abstracts, a total of 10 articles matched the eligible criteria. After reading the full articles, 2 were excluded because of the absence of the heat-treated instruments in the experimental design and 3 due to the lack of a control group using heat-treated instruments without autoclave sterilization. From the 5 included studies, 1 presented a low risk of bias, 3 presented moderate and 1 high risk. It was observed heterogeneous findings in the included studies, with autoclave sterilization cycles increasing, decreasing or not affecting the cyclic fatigue life of heat-treated NiTi instruments. However, the retrieved studies evaluating the cyclic fatigue resistance of endodontic instruments presented different protocols and assessing outcomes, this variability makes the findings less comparable within and also between groups and preclude the establishment of an unbiased scientific evidence base. Conclusions: Considering the little scientific evidence and considerable risk of bias, it is still possible to conclude that autoclave sterilization procedures appear to influence the cyclic fatigue resistance of heat-treated NiTi instruments.

• 대한치과의사협회지
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• 제52권2호
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• pp.60-68
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• 2014

Nickel-Titanium(NiTi) rotary instruments have brought a big step toward "efficient" practice of endodontic procedure. The rotary files help clinicians to reduce their working time and also increase the clinical success rate with minimal procedural errors by stainless steel instruments. In spite of these advantages, NiTi instruments still have a few drawbacks including unpredictable fatigue fracture. Clinicians may reduce the potential risk of instruments fracture by following some clinical guidelines for rotary instruments. In some clinical cases of instruments fracture, we may try to remove the instruments' fragments or bypass the fragment to reach the apical canal. In some limited cases, the fractured instruments' fragments would not jeopardize the clinical prognosis of root canal treatment. However, it is impossible to be overemphasized that the fragment removal is more difficult than the prevention of fracture. Clinicians need to understand the fracture mechanisms and, in clinic, need to discard the used instruments timely.

• 대한치과의사협회지
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• 제54권8호
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• pp.640-650
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• 2016

Nickel-Titanium (NiTi) rotary instruments have brought a big step toward "efficient" practice of endodontic procedure. The rotary files help clinicians to reduce their working time and also increase the clinical success rate with minimal procedural errors. However, NiTi instruments still have a few drawbacks including unpredictable fatigue fracture. Clinicians may reduce the potential risk of instruments fracture by following some clinical guidelines for rotary instruments. In some clinical cases of instruments fracture, we may try to remove the instruments' fragments or bypass the fragment to reach the apical canal. In some limited cases, the fractured instruments' fragments would not jeopardize the clinical prognosis of root canal treatment. Nevertheless, it is impossible to be overemphasized that the prevention of file fracture is much easier than the removal of fracture fragment. Clinicians need to understand the fracture mechanisms and, in clinic, need to discard the used instruments timely.

• Restorative Dentistry and Endodontics
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• 제37권4호
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• pp.220-227
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• 2012

Objectives: The study was to compare the shaping ability of Reciproc (VDW) and WaveOne (Dentsply Maillefer) instruments compared with ProTaper, Profile and hand instrument during the preparation of simulated root canals. Materials and Methods: Five groups (n = 5) were established. Reciproc, WaveOne, ProTaper, Profile and K file (K-flexo file) were used to prepare the resin simulated canals. A series of preoperative and postoperative images were taken by a microscope and superimposed in 2 different layers. The amount of resin removed from both the inner and the outer sides of the canal was measured to the level of 10 mm from the apical tip, with a 1 mm increment. Results: The mean of resin removal from the inner canal wall was not different from the outer canal wall for Reciproc and WaveOne groups at apical third (1 - 3 mm level). There was no difference in the change of working length and maintenance of canal curvature. NiTi instruments are superior to stainless-steel K file in their shaping ability. Conclusions: Within the limitation of this present study, Reciproc and WaveOne instruments maintained the original canal curvature in curved canals better than ProTaper and Profile, which tend to transport towards the outer canal wall of the curve in the apical part of the canal.

• 구강회복응용과학지
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• 제27권1호
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• pp.99-107
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• 2011

비외과적 재근관치료의 주된 목표는 치근주변의 치유를 위하여 근관 공간을 완전히 멸균하는 것이며, 이 목표를 달성하기 위해서는 이전 충전물질의 완전한 제거가 요구된다. 전통적으로 근관충전물질의 제거는 스테인리스스틸 수기구를 통해서 이루어져 왔으며 이는 시간과 노력이 많이 소요되는 작업이다. 최근 보다 효율적인 근관충전물질의 제거를 위해 재치료용 회전식 NiTi 기구가 소개되었다. 이 연구에서는 만곡된 근관에서의 스테인리스스틸 수기구, ProTaper Universal Retreatment (Dentsply Maillefer, Ballaigues, Switzerland), Mtwo retreatment (Sweden & Martina, Padova, Italy)의 gutta-percha 제거 효율을 비교하였다. 재치료 후 근관 내 남겨진 gutta-percha의 양은 실험군 사이에 유의한 차이가 발견되지 않았다. 하지만 재치료에 소요된 시간은 재치료용 회전식 NiTi 기구를 이용한 실험군에서 더 적게 소요되는 것으로 나타났다.

• 구강회복응용과학지
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• 제28권4호
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• pp.371-383
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• 2012

성공적인 근관치료를 위하여 원래 근관 형태를 따르는 근관 성형 과정이 중요하다. 그러나 대부분의 근관은 만곡되어 있고, 근관 성형 기구는 직선의 금속을 기본으로 만들어지기 때문에 근관 성형 후 만곡 근관이 원래 근관 형태를 벗어나는 오류가 나타날 수 있다. 이런 오류들로 인하여 근관 치료가 실패할 수 있으므로 근관 성형시 원래 만곡형태를 유지할 수 있는 다양한 기술과 방법들이 소개되고 있다. 본 연구의 목적은 만곡 근관 형태의 레진 모형을 이용하여 기구의 형태와 사용방법이 다른 세 가지 Ni-Ti 파일을 사용하여 Ni-Ti 파일 종류에 따른 만곡 근관에 대한 성형 후 형태 유지능을 비교하는 것이다. 직경과 경사도가 ISO 15, 0.02인 30개의 레진모형을 사용하였다. 그룹 1은 Profile을 이용하여 #20/.06까지 근관 성형하였고, 그룹 2는 Mtwo를 이용하여 #35/.04까지 근관 성형하였으며, 그룹 3은 PathFile을 이용하여 glide path를 만들어준 다음 WaveOne 파일 중 Primary을 사용하여 근관 성형하였다. 기구 사용 전과 후의 레진모형을 스캔하여 디지털 이미지로 만들었다. 각 이미지를 중첩시킨 다음 Matlab r2010b 소프트웨어를 이용하여 곡률반경의 비(CRr)를 계산하였다. 이를 바탕으로 Ni-Ti file 간 성형 후 형태 유지능을 비교하기 위하여 1-way ANOVA를 이용하여 세 그룹의 CRr의 차이에 대한 유의성 검정을 시행하였다.(P<.05) 또한 continuous rotary system과 single file system간의 형태 유지능을 비교하기 위하여 independent t-test를 이용하였다.(P<.05) 곡률반경의 비(CRr)를 이용하여 Ni-Ti 파일 종류에 따른 만곡 근관의 형태 유지능을 비교한 결과 Ni-Ti file 간에는 통계적으로 유의한 차이가 있었다.(P<0.05) ProFile과 WaveOne은 Mtwo에 비해서 만곡 근관에서의 형태 유지능이 우수하게 나타났다.Ni-Ti 기구 사용 방법에 따른 만곡 근관 형태 유지능을 비교한 결과 continuous rotary system과 single file system 간에는 통계적으로 유의한 차이를 보이지 않았다.(P>0.05) 본 연구결과에 따르면, ProFile과 WaveOne은 Mtwo에 비하여 만곡 근관에서의 형태 유지능이 통계적으로 유의하게 높게 나타났으므로, ProFile과 WaveOne이 만곡근관에 대한 형태 유지능이 우수하다고 할 수 있다. 만곡근관에서의 형태 유지능에 있어서 continuous rotary system과 single file system은 만곡근관에서의 형태 유지능에 차이가 없다.

• 대한치과의사협회지
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• 제51권10호
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• pp.551-555
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• 2013

The purpose of this study was to give a guideline for selecting the nickel-titanium (NiTi) file by review from many studies. Since the early 1990s, several instrument systems manufactured from NiTi have been introduced into endodontic practice. The specific design characteristics vary, such as tip shape and size, cross sectional view, helix angle, and pitch space. Some of the early systems have been removed from the market or play only minor roles; others are still widely used. New designs continually are produced, but the extent to which clinical outcomes will depend on design characteristics is difficult to forecast. In this study, I have reviewed the different design characteristics in respect of the safety and efficiency. With the review from many studies, I concluded that the clinicians must be understand the specific design characteristics for selecting the ideal NiTi rotary instruments.