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RISS 인기검색어
- 검색키워드
- 저자 : 황호길(Ho-Keel Hwang) (검색결과 103 건)
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근관형성방법(根管形成方法)에 따른 모의근관형태(模擬根管形態)의 변화(變化)에 대(對)한 실험적(實驗的) 연구(硏究)
황호길,조재오,조영곤,Hwang, Ho-Keel,Cho, Jae-O,Cho, Young-Kgon 대한치과보존학회 1988 Restorative Dentistry & Endodontics Vol.13 No.1
The purpose of this study was to examine the morphological changes of different simulated canals according to the preparation procedures. With the use of clear casting resin, simulated straight and curved canals were created so that canal preparation procedures could be directly visualized and compared. Thirty clear polyester casting resin blocks which contained four simulated canals divided into three groups; Group A($0^{\circ}$), Group B($15^{\circ}$), and Group C($30^{\circ}$). In each block, 3 canals were prepared different preparation techniques, which were conventional method, step-back method, and giromatic filing. But, one canal was not prepared as a control group. The results were as follows: 1. There was no difference on canal shape among three canal preparation methods in straight canals (Group A). 2. When conventional method and Giromatic filing were used in curved canals (Group B, C), elbow, zip and hour-glass shape were formed in apical third. 3. When conventional method and Giromatic filing were used in curved canals (Group B, C), tear-drop appearance developed at the site of the canal exit in curved canals. 4. In curved canals (Group B, C), file tend to straighten within the canal. 5. There was no difference on canal shape according to curved angle in step-back method (p > 0.1). But there was significant difference on canal shape according to curved angle in conventional method and Giromatic filing (p < 0.001). 6. Step-back method was significantly more effective than conventional method and Giromatic preparation in morphologic aspects of apical third of original canals.
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황호길(Ho-Keel Hwang) 대한치과의사협회 2013 대한치과의사협회지 Vol.51 No.10
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.
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근관내 여러 가지 조건에 따른 Root-ZX의 정확도에 관한 연구
황호길,신영근,김평식,Hwang, Ho-Keel,Shin, Young-Guen,Kim, Pyung-Sik 대한치과보존학회 2000 Restorative Dentistry & Endodontics Vol.25 No.3
Currently frequency-dependent type electronic apex locators have been widely used to determine the working length in endodontic treatment. But, accuracy of electronic apex locators is controversial. The purpose of this study was to evaluate the accuracy of Root-ZX(Morita Co., Japan) at different kinds of conditions of root canals compared with the radiographic working length. The 40 extracted human anterior teeth with fully formed apices and without any caries were used. The radiographs were taken for working length with the 0.5mm short of #15 K-file tip just visible at the foramen under the surgical microscope(Carl Zeiss Co. Germany) at 25X. Then the electronic working lengths were determined with Root-ZX at the different kinds of conditions of root canals according to the presence of electrolyte and Crown-down pressureless technique. The results were as follows ; 1. There was no significant statistical difference in working length between radiograph and Root-ZX. 2. There was no significant statistical difference in electronic working length between the canal with electrolyte and without electrolyte. 3. There was no significant statistical difference in electronic working length between the canal without any instrumentation and after Crown-dow pressureless technique. 4. Of the total 40 root canals, 85% in Group I, 92.5% in Group II, 95% in Group III and 95% in Group IV using Root-ZX showed coincidence within 0.5mm accuracy compaing with the radiographic working length. The results showed that the Root-ZX can be use effectively for measuring the working length of root canal after instrumentation with Crown-down pressureless technique regardless of the presence of electrolyte in root canal.
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하악 대구치의 II형 근심 근관에서 치근단 부위의 만곡도 조사
윤혜림,이동균,황호길,Yun, Hye-Rim,Lee, Dong-Kyun,Hwang, Ho-Keel 대한치과보존학회 2012 Restorative Dentistry & Endodontics Vol.37 No.2
Objectives: The purpose of this study was to evaluate the buccolingual curvature at the apical one third in type II mesial canals of mandibular molars using the radius and angle of curvature. Materials and Methods: Total 100 mandibular molars were selected. Following an endodontic access in the teeth, their distal roots were removed. #15 H- or K-files (Dentsply Maillefer) were inserted into the mesiobuccal and mesiolingual canals of the teeth. Radiographs of the teeth were taken for the proximal view. Among them, type II canals were selected and divided into two subgroups, IIa and IIb. In type IIa, two separate canals merged into one canal before reaching the apex and in type IIb, two separate canals merged into one canal within the apical foramen. The radius and angle of curvature of specimens were examined. Results: In type II, mean radius of curvature in mesiolingual and mesiobuccal canals were 2.82 mm and 3.58 mm, respectively. The radius of the curvature of mesiolingual canals were significantly smaller than that of mesiobuccal canals in type II, and especially in type IIa. However, there were no statistically significant differences in radius of curvature between mesiobuccal and mesiolingual canals in type IIb and there were no significant differences in angle of curvature between type IIa and IIb. Conclusion: In this study, type II mesial canals of mandibular molars showed severe curvature in the proximal view. Especially, mesiolingual canals of type IIa had more abrupt curvature than mesiobuccal canals at the apical one third.
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금인레이 와동의 폭경에 따른 응력분포와 변위에 관한 유한요소법적 연구
신강석,조영곤,황호길,Shin, Gang-Suk,Cho, Young-Gon,Hwang, Ho-Keel 대한치과보존학회 1993 Restorative Dentistry & Endodontics Vol.18 No.2
The purpose of this study was to examine the clear concept of the designs for cavity preparations. Among the several parameters in cavity designs, profound understanding of isthmus width factor would facilitate selection of the appropriate cavity preparation for a specific clinical situation. In this study, the cavities were prepared on maxillary first premolar and filled with gold inaly. A two - dimensional model was composed of 1037 - node triangle elements. In this model, isthmus was varied in width at 1/4, 1/3 and 1/2 of intercuspal width and material properties were given for four element groups, i.e., enamel, dentin, pulp and gold. The 500N occlusal load varied in direction and it was examined using three types of load : concentrated load, divided load and distributed load. The models were also examined with empty cavities using the devided load and distributed load. These models were analyzed the displacement and strees distribution by the two - dimensional Finite Element Method. The results were as follows : 1. All experimental models which filled with gold inlay after cavity preparation were similar direction of displacement with control model under same load type. But in the models with empty cavities, as isthmus width was wider, the degree of displacement was increased at same load type. 2. Among the experimental models which were filled with gold inaly after cavity preparation, the model II showed the least stress concentration under concentrated load and divided load. But in the models with empty cavities, the model III showed the largest stress concentration and tooth fracture is expected regardless isthmus width. 3. All experimental models showed similar displacement pattern beneath restorative material under a concentrated load. In the models with empty cavities, a divided load resulted in a lingual displacement of the lingual cusp, but a distributed load resulted in a buccal displacement of the lingual cusp. In regard to the above results, the restored models were stronger than empty models in respect to the bending moment and tensile stress. The empty models are expected to fracture regardless isthmus width. The safest isthmus width was 1/3 of intercuspal distance, which showed the least stress concentration in respect to the effect of stress distribution.
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제 IV 형 근관에서 System B Plugger tip의 깊이에 따른 근관 충전 효과
최희원,김수미,황호길,Choi, Hee-Won,Kim, Soo-Mee,Hwang, Ho-Keel 대한치과보존학회 2008 Restorative Dentistry & Endodontics Vol.33 No.6
본 연구의 목적은 제 IV형 근관에서 Continuous Wave 가압법을 이용하여 충전할 때 System B Plugger tip의 깊이에 따른 근단부 밀폐효과를 평가하기 위함이다. 50개의 J형 만곡을 갖는 레진 블록에 부러진 F3 ProTaper 파일을 이용해 근관장에서 3mm 지점에 ledge를 형성한 후, F1 ProTaper Ni-Ti file을 이용해 레진 블록을 천공시켜 제 IV형 근관을 형성하고 System B Plugger tip의 깊이에 따라 3개의 실험군과 1개의 대조군으로 분류하였다. 제 IV형 근관의 거터퍼쳐와 실러의 길이는 확대경하에서 캘리퍼를 이용해 측정하였고 다음과 같은 결과를 얻었다. 1. 대조군의 설측 근관에서 거터퍼쳐와 실러 모두 관찰되지 않았다. 2. 3 mm군에서는 5 mm 또는 7 mm군에 비해 유의하게 많은 거터퍼쳐의 충전이 관찰되었다 (p<0.05). 3. 7 mm군에서는 유의하게 많은 빈 공간이 관찰되었다 (p<0.05). The purpose of this study was to evaluate the effect of the apical sealing according to the depth of the System B Plugger tip when root canal was filled with gutta-percha and sealer by Continuous Wave of Condensation technique in the Type IV canal. 50 simulated resin blocks with J-shaped curvature canals were instrumented by ProTaper (Dentsply Maillefer, Ballagiues, Switzerland) Ni-Ti files using the crown-down technique. Type IV canals were made using a broken ProTaper F3 Ni-Ti file for making a ledge at 3mm short from the working length. And ProTaper F1 Ni-Ti file was used for perforating resin block. The prepared Type IV canals were randomly divided into three experimental groups of 15 each according to the depth of System B Plugger tip. All of experimental groups were obturated with Continuous Wave of Condensation technique. The length of gutta-percha and sealer in lingual of the Type IV canals was measured with a measuring digital calliper under magnifying glass (${\times}2.3$). The results are as follows : 1. In control group, there was no gutta-percha and sealer in lingual canal. 2. 3 mm group showed relatively more gutta-percha than 5mm or 7 mm group (p<0.05). 3. 7 mm group did not showed gutta-percha and relatively more void were observed than 3mm or 5 mm group. (p<0.05) In conclusion, within the limits of the results of this experiment, the 3 mm depth of System B Plugger tip was acceptable for obturating the Type IV canal.
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