• Restorative Dentistry and Endodontics
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• v.29 no.1
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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.

• Restorative Dentistry and Endodontics
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• v.27 no.3
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• pp.277-283
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• 2002

The purpose of this study is to evaluate the two warm gutta-percha filling techniques by measuring the weight changes of resin blocks before and after canal filling in ribbon shaped canal. Simulated ribbon shaped root canals in 30 transparent resin blocks were instrumented to #40 using .06 taper Profile. 15 resin blocks were obturated with gutta-percha using cold lateral condensation. Warm lateral condensation using the Endotec II was then accomplished on the same 15 blocks. Another 15 resin blocks were obturated using the System B. All canals were obturated without sealer. The resin blocks were weighed after canal preparation and after each subsequent obturation, and then weight changes of the resin blocks were calculated The results were as follows. 1. Warm lateral condensation using Endotec II and continuous wave of condensation using System B produced a denser obturation of gutta-percha compared with conventional cold lateral condensation (p<0.01). 2. There was no significant difference between warm lateral condensation and continuous wave condensation. In conclusion, the warm gutta-percha condensation techniques like warm lateral condensation and continuous wave condensation can be expected to bring favorable canal obturation results in ribbon shaped canals.

• Restorative Dentistry and Endodontics
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• v.27 no.2
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• pp.196-206
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• 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.

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.573.1-573
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• 2001

The purpose of this study to evaluate several wann gutta-percha filling techniques using weight changes of resin blocks before and after canal filling in ribbon shaped canal. Simulated ribbon shaped root canals in 30 transparent resin blocks were instrumented to ＃40 using 06 taper Profile. 15 resin blocks were obturated with gutta-percha using cold lateral condensation. Warm lateral condensation using the Endotec II was then accomplished on the same 15 blocks. Another 15 resin blocks were obturated using the System B.(omitted)

• Restorative Dentistry and Endodontics
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• v.37 no.4
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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.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.346-356
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• 1998

The purpose of this study was to evaluate the sealing ability of various canal filling methods. Palatal roots of ninety extracted human maxillary molar teeth were resected at cementoenamel junction. Eighty of them were randomly assigned to four experimental groups, ten were served as positive and negative controls. All canals were prepared to # 40 using Profile. Experimental groups were obturated by lateral condensation technique, Thermafil technique, Continuous Wave of Condensation Technique, and down-pack & back-fill technique of Obtura-II, each with root canal sealer. Control groups were not obturated. Teeth were immersed in resorcinol-formaldehyde resin for 5 days at $4^{\circ}C$, and the resin was allowed to polymerize completely for 4 days at room temperature. Teeth were then ground horizontally at 1.5mm(level 1), 2.5mm(level 2), 3.5 mm(level 3) from the anatomical apex and examined with a stereomicroscope at ${\times}40$ magnification. The gap between the canal wall and the filling material, which was filled with the resin, was measured at each of the three levels. Each ratio of leakage was obtained by calculating the ratio of the area of the resin to the total area of the canal and was analyzed statistically (Rank-sum test). The results were as follows : 1. At the level 1, there was the greatest leakage in the Thermafil group and Obtura-II group, and the difference between the Obtura-II group and Continuous Wave of Condensation Technique group was statistically significant(p<0.05). 2. At the level 2, there was the least leakage in the Continuous Wave of Condensation Technique group, but there was no statistically significant difference between each group (p>0.05). 3. At the level 3, there was no statistically significant difference between each group(p>0.05).

• Journal of the Korea Furniture Society
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• v.19 no.2
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• pp.124-129
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• 2008

Moisture content of Larix kapempferi was maintained at 28% after air drying. 5% CCFZ solution penetration depth was observed through longitudinal tracheid and axial resin canal. Penetration depth was increased significantly from heartwood to sapwood and the penetration depth was found 1.3 times higher for sapwood measured at 15.0 second of penetration. On the other hand, liquid flow in sapwood and heartwood involved most liquid first entering the resin canals. Overall resin canal conducted 1.4 times more than tracheid. Latewood was found more permeable than in earlywood. At the beginning of penetration, the speed was high and then decreased in the course of time.

• Journal of the Korea Furniture Society
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• v.18 no.2
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• pp.138-142
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• 2007

Optical microscope was used to observe the difference of safranine penetration in Pinus densiflora, Pinus rigida, Pinus koraiensis and Larix kaempferi grown in Korea. It was found that Pinus koraiensis contained the highest number of ray parenchyma and ray tracheids. In longitudinal direction, latewood penetration was found higher than that of earlywood. The number of resin canals was found highest in Pinus koraiensis and lowest in Pinus rigida. The resin canal conducted safranine higher than longitudinal tracheids. In longitudinal direction, safranine diffused from longitudinal tracheid to ray parenchyma through the cross-field pits and from the longitudinal resin canal to ray parenchyma or longitudinal tracheid. Safranine diffused from longitudinal tracheid to its neighboring tracheid through bordered pit or ray parenchyma through the cross-field pits.

• Restorative Dentistry and Endodontics
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• v.30 no.5
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• pp.393-401
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• 2005

The purpose of this study was to compare the canal configuration after shaping by ProTaper rotary files and ProTaper hand files in resin simulated canals. Forty resin simulated canals with a curvature of J-shape and S-shape were divided into four groups by 10 blocks each Simulated root canals in resin block were prepared by ProTaper rotary files and ProTaper hand files using a crown-down pressureless technique All simulated canals were prepared up to size $\#25$ file at end-point of preparation. Pre- and post-instrumentation images were recorded with color scanner. Assessment of canal shape was completed with an image analysis program. Measurements were made at 0, 1, 2, 3, 4, 5, 6 and 7 mm from the apex. At each level, outer canal width, inner canal width, total canal width, and amount of transportation from original axis were recorded. Instrumentation time was recorded. The data were analyzed statistically using independent t-test. The result was that ProTaper hand files cause significantly less canal transportation from original axis of canal body and maintain original canal configuration better than ProTaper rotary files, however ProTaper hand files take more shaping time.

• Journal of Korean Society of Forest Science
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• v.15 no.1
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• pp.43-48
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• 1972

The variation of numbers of resin canal in cotyledon at different growing stages are observed and results are summarized as follows: 1. Resin canals of cotyledon are not found in May, but in September the average number was 3.26. 2. Unlike in later-formed needles, cotyledon resin canals were external and the range of resin canal numbers are 1 to 5. 3. Correlation coefficients between growing stages and resin canal numbers are significant. And correlations between resin canal numbers and leaf thickness, or the number and cross-section area are also highly significant. 4. Low correlation between resin canal and cotyledon number is observed.