• Restorative Dentistry and Endodontics
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• 제29권5호
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• pp.439-445
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• 2004

Continuous Wave 가압법으로 근관충전시 플러거 삽입 깊이에 따른 근관실러의 치근단 정출을 평가하고자 직선형의 단근관 및 15번 크기의 치근단공을 가지는 발거된 40개의 치아에서 0.06 경사도 40번 크기가 되게 니켈-티타늄 전동화일인 $ProFile^{\circledR}$로 근관을 형성하고 플러거 삽입깊이를 근단 3, 5 또는 7 mm로 하여 System $B^{TM}$를 이용한 Continuous Wave 가압법 및 측방가압법으로 근관을 충전하였다. 치근단으로 정출된 근관실러의 무게를 측정하여 일원변량분석법과 Duncan's Multiple Range Test로 통계분석하였다. 플러거 삽입깊이 3 mm 또는 5 mm의 Continuous Wave 가압 충전군은 삽입깊이 7 mm 가압충전 군 및 측방가압 충전군에 비해 유의하게 많은 근관실러의 치근단 정출을 나타내었다 (p < 0.05). 그러나 플러거 삽입깊이 3 mm군과 5 mm군 사이 및 플러거 삽입깊이 7 mm Continuous Wave 가압군과 측방가압 군 사이에는 유의한 차이가 나타나지 않았다 (p > 0.05). 본 연구의 결과로 보아 Continuous Wave 가압법으로 근관충전시에는 플러거 삽입깊이가 깊을수록 근관실러의 치근단 정출이 많음을 알 수 있다.

• Restorative Dentistry and Endodontics
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• 제7권1호
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• pp.7-15
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• 1981

This study was conducted to compare the cleansing effect of various irrigants and the function of the quantity of irrigants in apical region. One hundred sixty single rooted teeth were divided into four groups and fourty teeth in each group were individually enlarged and irrigated with each of four irrigants as they would be during clinical condition. The four tested irrigants were Normal saline solution, 3.5% NaOCl, 15% EDTA, and 50% Citric acid. In each group, twenty teeth were flushed with 2cc of each irrigant and another twenty teeth with 5cc of same irrigant after use of each instrument. After final flush and dry, the roots were split longitudinally and the degree of cleansing at apical portion were evaluated under Stereoscope by three observers. The typical specimens of each group were also examined under Scanning electron microscope. The results were as follows. 1. There were no significant difference of cleansing effect among the tested irrigants. 2. 5cc flushed groups have more samples that have high degree of cleansing than 2cc flushed groups. 3. The canals irrigated with 2cc showed the presence of many dentin chips, tissue debris and smeared layer, whereas the 5cc groups revealed relatively clean canal surface and less smeared layer under Scanning electron microscope. 4. The teeth flushed with 5cc of EDTA and with 5cc of Citric acid showed the most clean canal surface at Scanning fictures.

• 한국응용곤충학회지
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• 제46권1호
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• pp.117-122
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• 2007

전남지역 담수직파재배지에서 발생하여 피해를 주고 있는 왕우렁이를 방제하기 위해 오리 및 통발과 유인제를 이용하여 시험한 결과는 다음과 같다. 왕우렁이를 포식하는 오리는 작은 오리(700g)가 큰오리(1300g) 보다 더 많이 포식하였다. 작은 오리 1마리보다는 2마리 있을 경우 포식량이 더 많아 투입 2일째에 90% 이상의 우렁이를 섭식하였다. 왕우렁이와 오리를 동시에 투입하는 것 보다 왕우렁이 투입 7일후에 오리를 투입하는 것이 왕우렁이 방제에 효과적이었다. 또한 왕우렁이를 잡초제거 용으로 활용한 1개월 후부터는 오리를 어느 시기에 투입하더라도 왕우렁이 밀도를 억제시킬 수 있었다. 왕우렁이 월동이 끝나는 5월 상순에 오리를 $30m^2$ 당 4마리 투입함으로써 밀도를 억제할 수 있었다. 왕우렁이를 방제하기 위해 통발로 떡밥과 유인제를 혼합하여 유인한 결과 왕우렁이는 잉어용 떡밥에 menthol이 첨가된 통발에서 216마리/1주(週) 유인되었다.

• Journal of the Korean Wood Science and Technology
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• 제33권6호통권134호
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• pp.17-24
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• 2005

두께 30 mm 잣나무 판재를 증기와 4가지 건조방법으로 처리하였다. 처리된 판재의 변재에서 시편을 떼어내어 Darcy 법칙을 이용한 간단한 방법으로 섬유방향 비투과율을 비교하였다. 잣나무 변재의 섬유방향 수분이동기작을 조사하기 위해 시편을 알코올과 아세톤 추출한 후에 비투과율을 또 측정하였다. 측정된 비투과율은 측정시간에 따라 급격히 감소하는 것이 관찰되었다. 이는 Darcy 법칙에 어긋나는 것으로 음압에 의해 공기방울이 발생하여 이동통로를 막기 때문으로 설명할 수 있다. 처리방법에 따라 미추출 시편의 평균 비투과율은 다르게 나타났으며 용매추출에 의한 비투과율 변화도 처리방법에 따라 달리 나타났다. 처리방법에 따라 수지구내 잔류수지의 성질이 달라지기 때문으로 생각된다. 수지구내 잔류수지 형상을 SEM 사진으로 관찰하였다.

• Imaging Science in Dentistry
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• 제44권4호
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• pp.273-278
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• 2014

Purpose: This study was performed to investigate the course of the mandibular canal on panoramic radiography and the visibility of this canal on both panoramic radiography and cone-beam computed tomography (CBCT). Materials and Methods: The study consisted of panoramic radiographs and CBCT images from 262 patients. The course of the mandibular canal, as seen in panoramic radiographs, was classified into four types: linear, elliptical, spoon-shaped, and turning curves. The visibility of this canal from the first to the third molar region was evaluated by visually determining whether the mandibular canal was clearly visible, probably visible, or invisible. The visibihlity of the canal on panoramic radiographs was compared with that on CBCT images. Results: Elliptical curves were most frequently observed along the course of the mandibular canal. The percentage of clearly visible mandibular canals was the highest among the spoon-shaped curves and the lowest among the linear curves. On panoramic radiographs, invisible mandibular canals were found in 22.7% of the examined sites in the first molar region, 11.8% in the second molar region, and 1.3% in the third molar region. On CBCT cross-sectional images, the mandibular canal was invisible in 8.2% of the examined sites in the first molar region, 5.7% in the second molar region, and 0.2% in the third molar region. Conclusion: The visibility of this canal was lower in the first molar region than in the third molar region. The mandibular canal presented better visibility on CBCT images than on panoramic radiographs.

• Restorative Dentistry and Endodontics
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• 제40권2호
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• pp.123-127
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• 2015

Objectives: Glide path preparation is recommended to reduce torsional failure of nickel-titanium (NiTi) rotary instruments and to prevent root canal transportation. This study evaluated whether the repetitive insertions of G-files to the working length maintain the apical size as well as provide sufficient lumen as a glide path for subsequent instrumentation. Materials and Methods: The G-file system (Micro-Mega) composed of G1 and G2 files for glide path preparation was used with the J-shaped, simulated resin canals. After inserting a G1 file twice, a G2 file was inserted to the working length 1, 4, 7, or 10 times for four each experimental group, respectively (n = 10). Then the canals were cleaned by copious irrigation, and lubricated with a separating gel medium. Canal replicas were made using silicone impression material, and the diameter of the replicas was measured at working length (D0) and 1 mm level (D1) under a scanning electron microscope. Data was analysed by one-way ANOVA and post-hoc tests (p = 0.05). Results: The diameter at D0 level did not show any significant difference between the 1, 2, 4, and 10 times of repetitive pecking insertions of G2 files at working length. However, 10 times of pecking motion with G2 file resulted in significantly larger canal diameter at D1 (p < 0.05). Conclusions: Under the limitations of this study, the repetitive insertion of a G2 file up to 10 times at working length created an adequate lumen for subsequent apical shaping with other rotary files bigger than International Organization for Standardization (ISO) size 20, without apical transportation at D0 level.

• Restorative Dentistry and Endodontics
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• 제46권4호
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• pp.49.1-49.8
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• 2021

Objectives: To evaluate the fracture incidence of Reciproc R25 instruments (VDW) used during non-surgical root canal retreatments performed by students in a postgraduate endodontic program. Materials and Methods: From the analysis of clinical record cards and periapical radiographs of root canal retreatments performed by postgraduate students using the Reciproc R25, a total of 1,016 teeth (2,544 root canals) were selected. The instruments were discarded after a single use. The general incidence of instrument fractures and its frequency was analyzed considering the group of teeth and the root thirds where the fractures occurred. Statistical analysis was performed using the χ² test (p < 0.01). Results: Seven instruments were separated during the procedures. The percentage of fracture in relation to the number of instrumented canals was 0.27% and 0.68% in relation to the number of instrumented teeth. Four fractures occurred in maxillary molars, 1 in a mandibular molar, 1 in a mandibular premolar and 1 in a maxillary incisor. A greater number of fractures was observed in molars when compared with the number of fractures observed in the other dental groups (p < 0.01). Considering all of the instrument fractures, 71.43% were located in the apical third and 28.57% in the middle third (p < 0.01). One instrument fragment was removed, one bypassed, while in 5 cases, the instrument fragment remained inside the root canal. Conclusions: The use of Reciproc R25 instruments in root canal retreatments carried out by postgraduate students was associated with a low incidence of fractures.

• Restorative Dentistry and Endodontics
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• 제46권1호
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• pp.13.1-13.9
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• 2021

Objectives: This study aimed to evaluate and compare the efficacy of the S1 reciprocating system and the D-Race retreatment rotary system for filling material removal and the apical extrusion of debris. Materials and Methods: Sixty-four freshly extracted maxillary canines were shaped with size 10 and size 15 K-files, instrumented using ProTaper Gold under irrigation with 2.5% sodium hypochlorite (NaOCl), obturated according to the principle of thermo-mechanical condensation with gutta-percha and zinc oxide eugenol sealer, and allowed to set for 3 weeks at 37℃. Subsequently, the teeth were divided into a control group (n = 4), the D-Race rotary instrument group (n = 30), and the S1 reciprocating instrument group (n = 30). After classical retreatment, the canals were subjected to a complementary approach with the XP-Endo Shaper. Desocclusol was used as a solvent, and irrigation with 2.5% NaOCl was performed. Each group was divided into subgroups according to the timing of radiographic readings. The images were imported into a software program to measure the remaining filling material, the apical extrusion, and the root canal space. The data were statistically analyzed using the Z-test and JASP graphics software. Results: No significant differences were found between the D-Race and S1 groups for primary retreatment; however, using a complementary cleaning method increased the removal of remnant filling (p < 0.05). Conclusions: Classical removal of canal filling material may not be sufficient for root canal disinfection, although a complementary finishing approach improved the results. Nevertheless, all systems left some debris and caused apical extrusion.

• Restorative Dentistry and Endodontics
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• 제17권2호
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• pp.343-354
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• 1992

본 연구의 목적은 여러가지 근관충전법으로 충전된 근관의 폐쇄효과를 정선적 및 정량적으로 측정하여 각 충전법간의 폐쇄효과를 비교하므로써 정선적 측정법 및 정량적 측정법간의 상호 관계를 규명하는데 있다. 108개의 발거된 상악중절치 및 측절치와 상하악 견치에서 치관을 절제하고 통법대로 근관형성한 다음 4개군으로 나누어 제 I 군은 sealer를 사용하고 측방 가압근관충전법으로, 제 II 군은 sealer를 사용하고 저온연화 gutta-percha주입근관충전법으로, 제 III 군은 sealer를 사용하고 Thermafil근관충전법으로 그리고 제 IV 군은 sealer를 사용하지 않고 고온용융 gutta-percha주입근관충전법으로 충전하고 전 시편을 2 % methylene blue 용액 속에 근단부를 1mm담근 채 $37^{\circ}C$ 항온기에서 10일간 경과시켜 근단공을 통한 색소침투를 정선적 및 정량적으로 측정하여 다음의 결과를 얻었다. 정선적 측정에서는 II 군은 III군, I군 및 IV군보다, III군은 IV군보다 유의상 있게 색소침투가 적게 나타났으나 (P<0.05), 그 이외의 군들 상호간에는 유의한 차이가 없었다. 정량적 측정에서는 II 군이 가장 적게 나타나 I 군 및 IV군과는 유의한 차이가 있었으나 (P<0.05), III군과는 유의한 차이가 없었다(P>0.05). 정선적 측정과 정량적 측정과의 사이에는 미약하지만 유의한 상관관계가 있었다(r=0.3391, P<0.001).

• Restorative Dentistry and Endodontics
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• 제30권6호
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• pp.486-492
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• 2005

이 연구의 목적은 니켈-니타늄 파일의 삭제 성향과 엔진의 토크 조절 능력이 근관 성형에 미치는 영향을 평가하는 것이다 레진 모형 40개를 사용하였으며, Hero Shaper(R)와 Endo-Mate2을 이용한 HE군, Hero Shaper(R)와 Tecnika(R)를 이용한 HT군, Profile(R)과 Endo-Mate2(R)를 이용한 PE군, Profile(R)과 Tecnika(R)를 이용한 PT군으로 구분하여 근관성형 하였다. 각 군별 근관 성형 시간을 기록하였다. 근단공으로부터의 수직 이동 거리 1, 3 그리고 5mm 위치에서의 근관 삭제량, 중심이 동률을 산출하여 다음의 결론을 얻었다. 1. 근관 성형 시간은 HT군이 가장 빨랐다 (p<0.05). 2. 삭제량은 1mm지점에서 HE군이 PT군보다 컸고 (p<0.05), 3mm지점에서는 PT군이 다른 군들보다 작았다 (p<0.05). 5mm에서는 PE군이 PT군보다 컸다 (p<0.05). 3. 중심 이동률은 1mm 지점에서 HE군이 다른 군들보다 컸으며 (p<0.05), 5mm에서는 HT군이 PE군과 PT군보다 컸다 (p<0.05). 따라서 토크 조절이 되는 엔진을 사용하는 것이 근관의 변위를 적게 유발하고 과도한 삭제 량을 예방 할 수 있으며 근관 성형시간도 단축 할 수 있는 것으로 보이며 따라서 양호한 근관 성형 결과에 영향을 준다고 볼 수 있다.