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

• 대한치과보존학회:학술대회논문집
• /
• 대한치과보존학회 2003년도 제120회 추계학술대회 제 5차 한ㆍ일 치과보존학회 공동학술대회
• /
• pp.594-594
• /
• 2003

I. Objectives The purpose of this study is to determine if propagation of pre-existing manufacturing defects results in brittle fracture of NiTi rotary files by examining the fracture surface of the instrument by SEM, and to compare the fracture time of NiTi rotary files with different flute designs under cyclic loading. II. Materials and Methods This study examined three groups of rotary NiTi instruments (K3, ProFile, Hero). Of each group, 04 taper, size 30 and 06 taper, size 25 were selected.：120 in total. Surface defects were created by simulating the machining process of NiTi rotaries.(omitted)

• 대한치과보존학회:학술대회논문집
• /
• 대한치과보존학회 2003년도 제120회 추계학술대회 제 5차 한ㆍ일 치과보존학회 공동학술대회
• /
• pp.599-599
• /
• 2003

Endodontic rotary NiTi(Nickel-Titanium) files have several advantages, but they also have some problems. Fracture of instrument is the one of the problems. Cyclic fatigue fracture may not give a previous sign(ex, bending or distortion of the files) before it happen. It is affected by various factors. This study investigated time which takes for cyclic fatigue fracture to happen and fracture patterns with regard to different NiTi files and pecking motion.(omitted)

• Restorative Dentistry and Endodontics
• /
• 제23권1호
• /
• pp.257-268
• /
• 1998

During cleaning and shaping of narrow and curved canals, it is very difficult or nearly impossible to maintain the original canal shape. Procedural accidents such as, ledge, zipping, perforation, and instrument breakage are frequently occurred and even may lead to failure of endodontic therapy. To prevent these kinds of accidents, various instrumentation techniques and materials have been introduced. Recently some nickel titanium (NiTi) files are introduced and it is reported that These NiTi files created rounder preparations with less transportation than conventional instruments in curved canals. This study compared the change of the canal curvature and procedural accidents after instrumentation produced by stainless steel K-flexo file, and NiTi rotary files (Profile 29 and Quantec 2000). Thirty narrow and curved canals (25-45 degree) of extracted human molars were randomly divided into three groups. In group 1, canals were instrumented using a step-back and watch-winding/pull motion with K-flexo files. In group 2, canals were prepared with Profile 29. Group 3, canals were prepared with Quantec 2000 files. Before and after preparation of canals, periapical radiographs were taken and scanned. The change of canal curvature were measured using Photoshop 4.0 program and the incidence of procedural accidents were also evaluated. The results were as follows: 1. All group showed some loss of canal curvature after instrumentation. 2. Average loss of canal curvature was $6.70{\pm}5.31$ degree for group 1, $3.80{\pm}2.57$ degree for group 2, and $5.40{\pm}4.83$ degree for group 3. All group There was significant change in curvature between before and after instrumentation (p<0.05). But there was no statistical difference amoung 3 groups. 3. In group I, there were no procedural accidents, such as ledging, perforation, or instrument fracture. In group 2, two cases of ledge and one case of instrument fracture were produced Goup 3, each one case of ledge, perforation and instrument fracture were occurred. Whthin the limits of above results, It seems that NiTi rotary instrumentation is not All Mighty and if we use uncarefully, it is more dangerous to produce some procedural accidents than conventional hand files. But more studies should be taken to evaluate the exact effects of NiTi rotary instrumentations.

• Restorative Dentistry and Endodontics
• /
• 제27권2호
• /
• pp.196-206
• /
• 2002

본 연구는 근관의 치관부는 GT Rotary file을 이용하여 성형하고, 근단부는 K-Flexofile, ProFile .04, Lightspeed, HERO642 file로 성형하여 근관용 file의 근관성형력을 비교하는 것이다. 실험 표본으로는 resin simulated root canal blocks(Dentsply, Swiss)를 이용하였고 4개의 군으로 분류하여 실험을 실시하였다. 모든 resin block을 GT Rotary file(Dentsply, Swiss)을 이용하여 치관부를 형성한 후 근단부는 K-Flexofile(Dentsply, Swiss), ProFile .04 taper file(Denstply. Swiss), Lightspeed file(Lightspeed Tech., USA), HERO642 file(Micromega, France)로 ISO size #35까지 형성하였다. 성형 후 preparation time과 instrument failure를 측정하였고 최종 사용한 file을 resin block 내에 재위치시켜 working length의 변화량을 0.5mm 단위로 측정하였다. Resin debris에 의한 canal blockage를 조사하였으며, 근관 내의 인상을 채득하여 canal form을 평가하였다. 성형 전과 성형 후의 사진을 촬영하고 computer software를 이용하여 중첩시킨 후 canal aberration, canal transportation을 평가하여 다음과 같은 결과를 얻었다. 1. Preparation time, working length의 변화량, canal blockage, canal aberration, canal transportation에 있어서 Ni-Ti file이 stainless steel file에 비하여 우수하였다(p<0.05). 반면에 근관성형력에 있어서 canal form과 canal transportation을 제외하고는 세 Ni-Ti file 사이에는 유의차가 없었다(p>0.05). 2. Canal form 중 taper에 있어서 Lightspeed는 적절하지 못한 taper를 보여주었다(p<0.05). 3. Canal transportation에 있어서 Lightspeed 군과 HER0642 군이 K-Flexofile 군과 ProFile .04 군에 비해 적게 나타났고(p<0.05), 특히 만곡의 끝 부분에서는 Lightspeed 군이 가장 적게 나타났다(p<0.05). 이상과 같은 연구결과로 보아 부적절한 taper를 지니고 있던 Lightspeed fie과 HERO642 file 중 HERO642 file은 GT Rotary file과 함께 사용함으로써 적절한 taper로 형성할 수 있었으나 Lightspeed file은 효과적이지 못하였으므로 적절한 taper를 형성하기 위한 file이 치근의 중간부를 형성하기 위해 필요함이 확인되었다.

• Restorative Dentistry and Endodontics
• /
• 제23권1호
• /
• pp.477-486
• /
• 1998

Recently the development of rotary instrument makes it possible that in root canal treatment operator saves much more time, maintans original curved canal shape and easily prepares continuous tapered root canal. The purpose of this experiment was to examine the smoothness of the internal surface of prepared root canal and the effectiveness of debridement in prepared root canal by SEM for the comparison of hand and Ni-Ti rotary instrument. 25 extracted human teeth were access opened and # 10 K-type file was introduced into canal until it was appeared at the apical foramen. The working length was established by subtracting 0.5mm from this measurement. Group 1. The root canal preparation was done to # 30 with working length and then step-back until # 45 with K-Flexofile (Maillefer, Swiss). Group 2. Root canal preparation was done by Naviflex Ni-Ti file (Brasseler, USA) as the same technique with group 1. Group 3. Canal was prepared by Profile .04 (Maillefer, Swiss) taper until #30. Group 4. With use of Quantec (Tycom, USA) root canal was prepared from file number 1 to 8. In group 1 and 2, the root canal irrigant was NaOCl and the other groups, NaOCl and RC-prep (Premine Dental Products, USA) was used. The prepared teeth were notched with high-speed bur as bucco-lingual direction and fractured with chisel and mallet, then examined with SEM. Group 1 showed smooth internal surface. There were scratches mainly to the axial direction. Group 2 showed similar characteristics to those in group 1. Group 3 showed more smoother and linear cutting surface with bised scratches. Group 4 has the almost same characteristics group 3 and there was no difference in the file design. Ni-Ti rotary root canal instrument prepare the dentinal wall more smoother than hand instrument. The effectiveness of debridement was not fully affected by file design. The isthmus area and accessory canals of the root canal system were not prepared in any group. According to the result, hand and rotary type instrumentation techniques were effective in removal of major amount of tissue from root canal but it was not complete. In the direction of cutting movement there was difference between them.

• Restorative Dentistry and Endodontics
• /
• 제22권1호
• /
• pp.244-253
• /
• 1997

During preparation of narrow curved canals, procedural accidents such as, ledge, zipping, and transportation are frequently encountered and may lead to failure of endodontic therapy. To reduce these procedural errors and efficiently manage curved canals, various modifications in instrumentation technique and the design and flexibility of instruments have been advocated. This study compared the maintenance of the original canal curvature, cross sectional canal shape, and preparation time during instrumentation with stainless steel hand (K-Flexo) file, and nickel-titanium rotary files (Profile and Lightspeed). Thirty resin blocks with simulated curved canals of 20~25 degrees were used and divided into three groups of 10 each. In group 1, canals were instrumented using a quarter turn/pull technique with K-Flexofiles. Group 2 canals were prepared with rotary NiTi Profiles. Group 3 was prepared with rotary NiTi Lightspeed instrument. Before and after instrumentation, all canals were scanned using stereo microcope, FlexCam camera, and Photoshop 3.0 computer program. The results were as follows : 1. All groups showed some loss of canal curvature after instrumentation. Average loss of canal curvature was 8.6 degrees for K-Flexofile, 7.7 degrees for Profile, and 5.8 degrees for Lightspeed. Lightspeed exhibited significantly less curvature loss than K-Flexofile (p<0.05). 2. At the apical 1-mm level, Profile produced significantly rounder canals than Lightspeed (p<0.05). At the 3-mm level, Profile and Lightspeed exhibited significantly rounder canals than K-Flexofile (p<0.05). 3. Preparation with Lightspeed was significantly faster than Profile and K-Flexofile, and Profile was faster than K-Flexofile (p<0.05). 4. There was no significant difference in incidence of zipping between the hand K-Flexofile and rotary NiTi (Profile and Lightspeed) instruments. Most of apical canals were slightly widened near the apical foramen. As a results of this study, rotary NiTi instruments are superior to the K-Flexofile in regard to the maintenance of original canal curvature, cross-sectional shape and preparation time. But more investigations and studies should be needed to evaluate the ideal canal instrumentation.

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

• Restorative Dentistry and Endodontics
• /
• 제22권2호
• /
• pp.659-669
• /
• 1997

The goals of root canal instrumentation are complete debridement of pulp tissue, removal of microbes and affected dentin, and proper cleaning and shaping of the root canal space before obturation. Instrumentation with stainless steel files has been shown to produce undesirable results in canals, regardless of the improved technique or modified file type used. Nickel-Titanium(Ni-Ti) alloy has been shown to be exceptionally elastic, having a lower bending moment and lower permanent set after torsion, compared with similar gauge stainless steel. The purpose of this study was to evaluate the change of root canal prepared by Ni-Ti rotary and stainless steel instruments. Thirty-four single rooted teeth of similar shape and canal size were divided into three groups. The teeth were scanned by computed tomography before instrumentation. In group 1, canals were instrumented using a step-back technique with K-file. In group 2, canals were prepared with K-flex file using the same technique as group 1. Group 3 was prepared with nickel-titanium(Ni-Ti) rotary instrument using a manufacture's instruction. Instrumented teeth were again scanned using computed tomography, and reformated images of the uninstrumented canals were compared with images of the instrumented canals. K-flex file and Ni-Ti file caused significantly less canal transportation than K-file in the 8mm root canal section from the apex(p<0.05). K-flex file and Ni-Ti file produced more centered canal preparation than K-file in the 2mm section(p<0.05). Ni-Ti file maintained more precisely the center of the canal than K-flex file in the 10mm section (p<0.05). There was no difference in the removed volume of canals among each groups.

• Restorative Dentistry and Endodontics
• /
• 제31권3호
• /
• pp.161-168
• /
• 2006

근관형성을 하는 과정에서 기구가 파절될 가능성은 언제나 존재한다. File을 비롯하여 lentulo spiral, Gates-Glidden (GG) bur 또는 여타의 이물질도 근관 내에 남겨질 수 있다. 근래에는 수동 file에 비해 많은 장점을 가지고 있는 회전식 nickel-titanium (NiTi) file의 사용이 보편화 되고 있으나 기구의 높은 파절 경향이 문제가 되고 있다. NiTi file의 파절은 매우 빠른 시간내에 일어나고 예측이 불가능하며 임상가에게 정신적 stress를 가져다. 주기 때문에 임상가로 하여금 niTi file의 사용을 주저하게 만들기도 한다. 근관 내 기구가 파절되면 제거하는 것이 가장 최선의 해결 방법이다. 초음파 기기와 미세 현미경의 사용으로 파절된 기구의 제거율이 높아지고 있지만 제거하는 것이 쉬운 일만은 아니며 항상 제거가 가능한 것도 아니다. 그러므로 예방이 최선의 방법이라 할 수 있다. 본 증례에서는 근관 내 file이 파절된 경우에 있어 여러 가지 대처 방안에 대해 보고하고자 한다.