• 대한치과교정학회지
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• 제33권6호
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• pp.465-474
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• 2003

형상기억효과 및 초탄성 특성을 가진 니켈 타이타늄 와이어는 대단히 다양한 제품들이 출시되어 있어서, 보다 적절하면서도 경제적인 재료를 선택하고자 하는 임상가에게 어려움을 주고 있다. 이때, 교정 선재의 기계적 특성에 대한 실험적 연구는 임상가에게 유용한 정보를 제공해 줄 수 있다. 이 연구에서는 5군으로 나뉘어진 4종의 교정선재(stainless steel, multistranded, superelastic nickel titanium 그리고 themoactivated nickel titanium)에 대한 응력 -변형 실험을 통한 기계적 특성에 대한 비교를 시행하였다. 각 군의 교정선재에 대하여 일련의 여섯 가지 실험이 이루어졌다. 처음에는, 각 군에 대하여 선재가 파절될 때까지, 3차례의 실험이 이루어졌다. 그리고, 각 군에서 세 종류의 실험이 이루어졌는데, 표준하중에서 선재를 신장시켜서, 하중을 주었을 때와 하중을 제거하였을 때의 기계적 특성에 대한 신뢰할 만한 비교를 시행하였다. 각 군간의 차이를 알아보기 위하여 t-test를 시행하였다. 실험결과, 생리적인 치아이동을 위한 기계적 특성, 즉 강성, 탄성률, 힘의 발휘 특성 등을 고려해 볼 때, themoactivated nickel titanium, multistranded wire, stainless steel wire 순으로 바람직하였다. 초탄성은 superelastic nickel titanium에서 나타났다. 섭씨 37도에선 themoactivated nickel titanium의 형상기억효과가 나타났는데, 이것은 온도가 기계적 특성을 증진시키는데 중요하다는 것을 보여준다.

• Restorative Dentistry and Endodontics
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• 제22권1호
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• pp.291-304
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• 1997

The purposes of this study were to evaluate the changes in root canal configuration with canal instrumentation using different file types and techniques and to investigate most appropriate instrumentation technique in maintaining the original canal configuration with different file types. Fifty curved mesiobuccal or distobuccal canals of extracted human maxillary molar teeth were instrumented using a step-back technique with stainless steel K-files or nickel-titanium K-files, a crown-down pressureless technique with stainless steel K-files or nickel-titanium K-files and nickel-titanium engine-driven files. Radiographs were taken before and after instrumentation using a specially designed device that allowed for the pre-and postinstrumentation canals to be taken with the same X-ray angulation. Magnified X-ray images on a magnifier screen were traced and post instrumentation canal images were compared with the preinstrumentation ones. Changes in canal curvature and the incidence of procedural accidents were analyzed. The results were as follows : Crown-down pressureless technique with nickel-titanium K-files and nickel-titanium engine-driven filing produced no significant changes in canal curvature (p>0.05), while the step-back technique with stainless steel K-files or nickel-titanium K-files (p<0.01) and the crown-down pressureless technique with stainless steel K-files (p<0.05) produced significant changes. With nickel-titanium K-file, crown-down pressureless technique produced significantly less changes in canal curvature than step-back technique (p<0.05), while there was no significant difference between techniques with stainless steel K-files (p>0.05). File types exerted no significant influences in the changes of canal curvature both in the step-back technique and crown-down pressureless technique (0>0.05). Regardless of the file types used, step-back technique produced more procedural accidents such as ledge or elbow formation, apical zipping and apical transportation than the crowndown pressureless technique and nickel-titanium engine-driven filing. Both with stainless steel K-files and with nickel-titanium K-files, the incidence of apical extrusion of canal debris was higher in step-back technique than in crown-down pressureless technique.

• 대한치과교정학회지
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• 제36권5호
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• pp.349-359
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• 2006

니켈-티타늄 합금은 높은 spring-back성질, 초탄성 효과, 형상기억 효과 등의 장점을 가지고 있으나 성형이 어렵다는 단점을 가지고 있다. 본 연구에서는 니켈-티타늄 와이어의 굴곡을 위한 열처리 시에 나타나는 부하-변위 곡선의 변화 및 상전이 온도 변화와 같은 물성 변화 양상을 조사하고자 하였다. 수종의 니켈-티타늄 와이어를 열처리를 시행하지 않은 군, 전기저항 열처리 장치를 이용하여 와이어 단면적에 따라 제조회사에서 권장하는 전류를 기초로 하여 $00.016"\;{\times}\;00.022"$ (5 A, 7 sec), $0.018"\;{\times}\;0.025"$ (6 A, 7 sec) 그리고 $0.0215"\;{\times}\;0.028"$ (7 A, 8 sec) 와이어를 열처리만 시행한 실험군, 열처리를 시행하여 굴곡을 부여한 실험군 그리고 열처리 시간을 1초 증가시켜 굴곡을 부여한 실험군으로 분류하여 3점 굴곡 실험과 시차주사열량측정을 하여 다음과 같은 결과를 얻었다. $0.016"\;{\times}\;0.022"$, $0.018"\;{\times}\;0.025"$ 그리고 $0.0215"\;{\times}\;0.028"$ 니켈-티타늄 와이어에서 굴곡을 부여하지 않고 열처리만 시행한 실험군이 열처리를 시행하지 않은 대조군에 비해 부하-변위 곡선이 상방 이동되어 초탄성 현상에 의한 평탄역(loading and unloading plateau)의 힘이 더 증가되었다. $0.016"\;{\times}\;0.022"$, $0.018"\;{\times}\;0.025"$ 그리고 $0.0215"\;{\times}\;0.028"$ 와이어에서 열처리만 시행한 실험군이 열처리를 시행하지 않은 군보다 더 낮은 austenite finish ($A_f$) 온도를 보였다. $0.018"\;{\times}\;0.025"$ 및 $0.0215"0.028"$ 와이어에서 열처리를 시행하여 굴곡을 부여한 실험군은 열처리만 시행한 실험군과 열처리를 시행하지 않은 대조군에 비해 부하-변위 곡선이 상방 이동되었으며, 열처리 시간을 1초 증가시켜 굴곡을 부여한 실험군에서 가장 높은 부하-변위 곡선을 나타냈다. $0.018"\;{\times}\;0.025"$ 그리고 $0.0215"\;{\times}\;0.028"$ 와이어에서 $A_f$ 온도는 열처리 시간을 1초 증가시켜 굴곡을 부여한 실험군에서 가장 낮게 관찰되었고 열처리를 시행하여 굴곡을 부여한 실험군, 열처리만 시행한 실험군 그리고 열처리를 시행하지 않은 대조군 순으로 높게 관찰되었다. 이상의 결과를 종합할 때, 임상에서 니켈-티타늄 합금 와이어에 굴곡을 부여하기 위해 열처리하는 경우 초탄성 특성은 유지될 수 있으나, 부하-변위 곡선의 상방 증가가 나타나므로, 와이어에 의한 교정력이 증가될 수 있음에 유의하여야 한다.

• Restorative Dentistry and Endodontics
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• 제20권2호
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• pp.758-767
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• 1995

The purpose of this study was to evaluate canal shaping ability after canal preparation by using engine-driven nickel-titanium file and endosonic file in curved canals. 30 mesiobuccal canals of molars extracted within recent 3 months were divided into 3 groups. Group I and group II were prepared by using engine-driven nickel-titanium Gates-Glidden drill type and the engine-driven nickel-titanium file type. Group III prepared by using en do sonic file. The image of preinstrumented canals was taken by X-ray. The image of postinstrumented canal was taken by X-ray in the same condition of preinstrumentation. A magnified X-ray image on magnifier screen was traced and then compared the preinstrumentated canal image with the postinstrumentated canal image by superimposing method. The following results were obtained : 1. In the change of canal curvature, the engine-driven nickel-titanium Gates-Glidden drill type showed the least change and the ultrasonically filing showed the greatest change. 2. In the percentage of canal enlargement, the engine-driven nickel-titanium file type was greatest at all level(p<0.05), the apex of all group was the greatest, the difference of ultrasonically filing group showed greater between apex and cervix. 3. The percentage of canal enlargement on convex side was greater than that of on concave side in apex of each group(p<0.05). In the ultrasonically filing group, both sides of canal enlargement showed sharply difference(p<0.01). 4. The percentage of canal enlargement on convex side was greater than that of on concave side in the third of cervix of the engine-driven nickel-titanium file type and the ultrasonically filling. The percentage of canal enlargement of convex and concave side in the third of middle of the engine-driven nickel-titanium Gates-Glidden drill type show a similar canal enlargement between convex side and concave side. As above result, the engine-driven nickel-titanium file type was greater in canal enlargement than the other instruments. The engine-driven nickel-titanium Gates-Glidden dirll type was efficient endodontic instrument for curved canal preparation because it was least change in canal curvature.

• JSTS:Journal of Semiconductor Technology and Science
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• 제13권3호
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• pp.252-258
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• 2013

In this paper, a thermally stable nickel silicide technology using the co-sputtering of nickel and titanium atoms capped with TiN layer is proposed for nano-scale metal oxide semiconductor field effect transistor (MOSFET) applications. The effects of the incorporation of titanium ingredient in the co-sputtered Ni layer are characterized as a function of Ti sputtering power. The difference between the one-step rapid thermal process (RTP) and two-step RTP for the silicidation process has also been studied. It is shown that a certain proportion of titanium incorporation with two-step RTP has the best thermal stability for this structure.

• Restorative Dentistry and Endodontics
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• 제23권1호
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• pp.391-400
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• 1998

The aim of this study was to determine the shaping ability of stainless-steel K file (S-S K file), nickel-titanium K file (Ni-Ti K file) and engine driven nickel-titanium file (Quantec file) in resin simulated root canal. Computed tomography was used to evaluate the change of the root canal morphology. Thirty nine resin simulated root canal were divided into four groups (A:12, B:12, C:12, D:3). Resin simulated canals were scanned by computed tomography before instrumentation (1st C-T scan). Canals were instrumented using step back preparation technique with S-S K file in group A and Ni-Ti K file in group B. Group C was prepared with engine driven Ni-Ti file. Group D was uninstrumented to compare the 1st C-T scan images with 2nd C-T scan images of root canal. Instrumented canals were again scanned using computed tomography (2nd C-T scan), and reformated images of the uninstrumented canals were compared with images of the instrumented canals. In the sections of 2mm and 6mm from the apex, Quantec file caused significantly less canal transportation than S-S K file and Ni-Ti K file (p<0.05). Quantec file produced more centered than S-S K file and Ni-Ti K file in the sections of 2mm and 4mm from the apex (p<0.05). There was no significant difference in the removed volume of canals among the each groups (p>0.05). However the removed canal volume from the apex to 5mm were significantly higher than them from 5mm to 1mm (p<0.05) in each groups. Under the conditions of this study, preparation with Quantec file was more effective and produce more appropriate canal shapes than S-S K file and Ni-Ti K file.

• 대한치과보철학회지
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• 제33권3호
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• pp.584-609
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• 1995

The purpose of this study was to evaluate the difference of the galvanic corrosion behaviour of the titanium in contact with gold alloy, silva-palladium alloy, and nickel-chromium alloy using the immersion and electrochemical method. And the effects of galvallit couples between titanium and the dental alloys were assessed for their usefulness as materials for superstructure. The immersion method was performed by measuring the amount of metal elementsreleased by Inductivey coupled plasma emission spectroscopy(ICPES) The specimen of fifteen titanium plates, the five gold alloy, five silver-palladium, five nickel-chromium plates, and twenty acrylic resin plates ware fabricated, and also the specimen of sixty titanium plugs, the thirty gold alloy, thirty silver-palladium, and nickelc-hromium plugs were made. Thereafter, each plug of gold alloy, silver-palladium, and nickel-chromium inserted into the the titanium and acrylic resin plate, and also titanium plug inserted into the acrylic resin plate. The combination specimens uf galvanic couples immersed in 70m1 artificial saliva solution, and also specimens of four type alloy(that is, titanium, gold, silver-palladium and nickel-chromium alloy) plugs were immersed solely in 70m1 artificial sativa solution. The amount of metal elements released was observed during 21 weeks in the interval of each seven week. The electrochemical method was performed using computer-controlled potentiosta(Autostat 251. Sycopel Sicentific Ltd., U.K). The wax patterns(diameter 11.0mm, thickness,in 1.5mm) of four dental casting alloys were casted by centrifugal method and embedded in self-curing acrylic resin to be about $1.0cm^2$ of exposed surface area. Embedded specimens were polished with silicone carbide paper to #2,000, and ultrasonically cleaned. The working electrode is the specimen of four dental casting alloys, the reference electrode is a saturated calmel electrode(SCE) and the ounter electrode is made of platinum plate. In the artificial saliva solution, the potential scanning was carried out starting from-700mV(SCE) TO +1,000mV(SCE) and the scan rate was 75mV/min. Each polarization curve of alloy was recorded automatically on a logrithmic graphic paper by XY recorder. From the polarization curves of each galvanic couple, corrosion potential and corrosion rates, that is, corrosion density were compared and order of corrosion tendency was determined. From the experiments, the following results were obtained : 1. In the case of immersing titanium, gold alloy, silver-palladium alloy, and nickel-chromium alloysolely in the artificial saliva solution(group 1, 2, 3, and 4), the total amount of metal elements released was that group 4 was greater about 2, 3 times than group 3, and about 7.8 times than group 2. In the case of group 1, the amount of titanium released was not found after 8 week(p<0.001). 2. In the case of galvanic couples of titanium in contact with alloy(group 5, 6), the total amount of metal elements released of group 5 and 6 was less than that of group 7, 8, 9, and 10(p<0.05). 3. In the case of galvanic couples of titanium in contact with silver-palladium alloy(group 7, 8), the total amount of metal elements released of group 7 was greater about twice than that of group 5, and that of group 8 was about 14 times than that of group 6(p<0.05). 4. In the case of galvanic couples of titanium in contact with nickel-chromium alloy(group 9, 10), the total amount of metal elements released of group 9 and 10 was greater about 1.8-3.2 times than that of group 7 and 8, and was greater about 4.3~25 times than that of group 5 and 6(p<0.05). 5. In the effect of galvanic corrosion according to the difference of the area ratio of cathode and anode, the total amount of metal elements released was that group 5 was greater about 4 times than group 6, group 8 was greater about twice than group 7, and group 10 was greater about 1.5 times than group 9(p<0.05). 6. In the effect of galvanic corrosion according to the elasped time during 21 week in the interval of each 7 week, the amount of metal elements released was decreased markedly in the case of galvanic couples of the titanium in contact with gold alloy and silver-palladium alloy but the total amount of nickel and beryllium released was not decreased markedly in the case of galvanic couples of the titanium in contact with nickel-chromium alloy(p<0.05). 7. In the case of galvanic couples of titanium in contact with gold alloy, galvanic current was lower than any other galvanic couple. 8. In the case of galvanic couples of titanium in contact with nickel-chromium alloy, galvanic current was highest among other galvanic couples.

• Restorative Dentistry and Endodontics
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• 제29권1호
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• pp.44-50
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• 2004

This study compared the shaping ability of nickel-titanium rotary files with different rake angle and radial land. The nickel-titanium files used in this study were Profile(Dentsply, Maillefer, Ballaigues, Switzerland), Hero 642(Micromega, Besancon, France) and K3 (SybronEndo, Glendora, Ca, USA) file. Resin blocks substituted for root canals. 36 resin blocks were divided into 3 groups with 12 canals each The time for canal preparation was recorded. The images of pre- and postoperative resin canal were scanned and those were superimposed Amounts of canal deviation, total canal widths, inner canal widths, and outer canal widths were measured at apical 1, 2 ,3, 4, 5, 6, and 7mm levels. The amount of canal deviation was the smallest in Profile group , and the time far canal preparation was the shortest in Hero 642 group. K3 group resulted in competent characteristics in both measurements. Positive rake angle seemed to result in fast shaping of root canal and radial land guide the instrument in center of the canals and around curvatures. Radial land also tended to reduce the sense of screwing into the root canal. The proper selection of the nickel-titanium fie based on the knowledge about file design is needed for the safer, simpler and faster root canal therapy.

• 대한치과교정학회지
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• 제28권6호
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• pp.927-935
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• 1998

본 연구의 목적은 수종의 nickel titanium 호선을 열멸균 처리 하였을 때 나타나는 물리적성질과 표면상태의 변화를 정량적으로 평가하고자 하는 것이다. 연구에 사용된 재료는 국산제품을 포함한 4종의 .$016\times.22$ 각형 nickel-titanium호선이며, 이들을 건열소독($180^{\circ}C$, 60분)군과 가압증기멸균($121^{\circ}C$, 15-20 psi, 30분)군, 그리고 아무런 처리를 하지 않은 대조군으로 구분하였다. 인정특성은 Inston (Model 4466, load cell capacity:1000kg)을 이용하여 표점거리 40mm, cross head는 분당 5mm의 속도, 실온의 조건에서 평가하였으며 쳐대인장강도와 연신율, 그리고 탄성률을 측정 및 계산하였다. 표면상태는 주사전자현미경과 profilometer로써 평가하였고, 1-test를 이용하여 통계적 분석을 하였다. 결과는 다음과 같다. 1. 실험에 사용된 nickel-titanium호선들은 모두 두가지 열멸균 처리에 의해 인장특성에 있어서 유의할 만한 변화를 보이지 않았다/ 2. 대조군에서 NiTi가 가장 높은 펴ㅛ면거칠기를 보였고, Align과 Sentalloy는 동일한 정도의 값을, Optimalloy는 가장 낮은 값을 지니고 있었다. 3. Align과 Optimalloy는 두가지 열멸균처리 후에 모두 유의할 만한 표면상태의 변화를 보이지 않았다. 그러나 NiTi는 건열소독후에 표면거칠기의 증가를 보였으며 Sentalloy는 두가지 열멸균후에 표면상태의 변화와 표면거칠기의 유위한 증가를 보였다.

• Restorative Dentistry and Endodontics
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• 제29권3호
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• pp.212-218
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• 2004

The purpose of this study was to quantify the amount of remaining gutta-percha/sealer on the walls of root canals when three types of nickel-titanium rotary instruments (Profile. ProTaper and $K^3$) and a hand instrument(Hedstrom file) used to remove these materials. The results of this study were as follows: 1. In the total time for gutta-percha removal. Profile group was the fastest and followed by $K^3$, Protaper, Hedstrom file group. 2. In case of the evaluation of the volume of remained gutta-percha from radiograph. $K^3$ group got the highest score and followed by Protaper. Hedstrom file. Profile group in the apical 1/3. 3. In case of the evaluation of the volume of gutta-percha remained from stereomicroscope, $K^3$ group got the highest score and followed by Protaper. Hedstrom file. Profile group in the apical 1/3. These results showed that instrumentation using nickel-titanium rotary instrument groups was faster than that using hand instrument group. The effect of gutta-percha removal using Profile group was better than that using Protaper and $K^3$ group in the nickel-titanium rotary instrument groups.