• Restorative Dentistry and Endodontics
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• 제38권1호
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• pp.21-25
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• 2013

Objectives: The aim of this study was to evaluate the shaping ability of newly marketed single-file instruments, Wave One (Dentsply-Maillefer) and Reciproc (VDW GmbH), in terms of maintaining the original root canal configuration and curvature, with or without a glide-path. Materials and Methods: According to the instruments used, the blocks were divided into 4 groups (n = 10): Group 1, no glide-path / Wave One; Group 2, no glide-path / Reciproc; Group 3, #15 K-file / Wave One; Group 4, #15 K-file / Reciproc. Pre- and post-instrumented images were scanned and the canal deviation was assessed. The cyclic fatigue stress was loaded to examine the cross-sectional shape of the fractured surface. The broken fragments were evaluated under the scanning electron microscope (SEM) for topographic features of the cross-section. Statistically analysis of the data was performed using one-way analysis of variance followed by Tukey's test (${\alpha}$ = 0.05). Results: The ability of instruments to remain centered in prepared canals at 1 and 2 mm levels was significantly lower in Group 1 (p < 0.05). The centering ratio at 3, 5, and 7 mm level were not significantly different. Conclusions: The Wave One file should be used following establishment of a glide-path larger than #15.

• Restorative Dentistry and Endodontics
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• 제39권1호
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• pp.7-11
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• 2014

Objectives: The aim of this study was to compare the dimensional standard of several nickel-titanium (Ni-Ti) rotary files and verify the size conformity. Materials and Methods: ProFile (Dentsply Maillefer), RaCe (FKG Dentaire), and TF file (SybronEndo) #25 with a 0.04 and 0.06 taper were investigated, with 10 in each group for a total of 60 files. Digital images of Ni-Ti files were captured under light microscope (SZX16, Olympus) at $32{\times}$. Taper and diameter at $D_1$ to $D_{16}$ of each files were calculated digitally with AnalySIS TS Materials (OLYMPUS Soft Imaging Solutions). Differences in taper, the diameter of each level ($D_1$ to $D_{16}$) at 1 mm interval from (ANSI/ADA) specification No. 101 were statistically analyzed using one-way ANOVA and Scheffe's post-hoc test at 95% confidence level. Results: TF was the only group not conform to the nominal taper in both tapers (p < 0.05). All groups except 0.06 taper ProFile showed significant difference from the nominal diameter (p < 0.05). Conclusions: Actual size of Ni-Ti file, especially TF, was different from the manufacturer's statements.

• Restorative Dentistry and Endodontics
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• 제45권2호
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• pp.22.1-22.10
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• 2020

Objectives: This study investigated the influence of glide path size and operating kinetics on the time to reach the working length and the fracture resistance of Twisted File (TF) and Endostar E3 files. Materials and Methods: A total of 120 mandibular single-rooted premolars were selected. Two methods of kinetic motion (TF adaptive and continuous rotary motion) and file systems (TF and Endostar E3) were employed. The files were used in root canals prepared to apical glide path sizes of 15, 20, and 25. The time taken to reach the working length and the number of canals used before the instrument deformed or fractured were noted. Fractured instruments were examined with scanning electron microscopy. Results: The TF system took significantly more time to reach the working length than the Endostar E3 system. Both systems required significantly more time to reach the working length at the size 15 glide path than at sizes 20 and 25. A greater number of TFs than Endostar E3 files exhibited deformation, and a higher incidence of instrument deformation was observed in adaptive than in continuous rotary motion; more deformation was also observed with the size 15 glide path. One TF was fractured while undergoing adaptive motion. Conclusions: No significant difference was observed between continuous rotary and adaptive motion. The TF system and adaptive motion were associated with a higher incidence of deformation and fracture. Apical glide path sizes of 20 and 25 required significantly less time to reach the working length than size 15.

• Restorative Dentistry and Endodontics
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• 제44권2호
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• pp.22.1-22.8
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• 2019

Objectives: The aim of this study was to investigate the effect of glide path preparation with PathFile and ProGlider nickel-titanium (NiTi) files on the cyclic fatigue resistance of WaveOne NiTi files. Materials and Methods: Forty-four WaveOne Primary files were used and divided into four groups (n = 11). In the first group (0 WaveOne), the WaveOne Primary files served as a control group and were not used on acrylic blocks. In the 1 WaveOne Group, acrylic blocks were prepared using only WaveOne Primary files, and in the PF+WaveOne group and PG+WaveOne groups, acrylic blocks were first prepared with PathFile or ProGlider NiTi files, respectively, followed by the use of WaveOne Primary files. All the WaveOne Primary files were then subjected to cyclic fatigue testing. The number of cycles to failure was calculated and the data were statistically analyzed using one-way analysis of variance (ANOVA) and the Tukey honest significant difference multiple-comparison test at a 5% significance level. Results: The highest number of cycles to failure was found in the control group, and the lowest numbers were found in the 1 WaveOne group and the PF+WaveOne group. Significant differences were found among the 1 WaveOne, PF+WaveOne, and control groups (p < 0.05). No statistically significant differences were found between the PG+WaveOne group and the other three groups (p > 0.05). Conclusion: Glide path preparation with NiTi rotary files did not affect the cyclic fatigue resistance of WaveOne Primary files used on acrylic blocks.

• Restorative Dentistry and Endodontics
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• 제35권5호
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• pp.374-379
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• 2010

연구목적: 근관의 만곡도가 니켈-티타늄 전동파일의 screw-in effect에 미치는 영향을 평가하고자 하였다. 연구 재료 및 방법: 0, 10, 20, 그리고 30도의 만곡을 가지는 80개의 레진모형근관 (Nissin Dental Prod. Inc.)에서 0.06 경사도 30번 전동화일 (ProTaper, Dentsply-Maillefer)을 분당 300회전, 단일 pecking 동작으로 기구조작하였으며 dynamometer를 이용하여 발생한 screw-in force를 측정하였다. 결과치는 one-way ANOVA로 통계처리 하였고, Scheffe multiple range test를 사용하여 95% 수준에서 유의성을 검정하였다. 결과: 근관의 만곡도가 작을수록 screw-in force가 높게 나타났으며 (p < 0.001), 모든 그룹 간에 유의성 있는 차이를 보였다. 결론: 이 결과로 미루어 볼 때, 근관의 만곡도가 작을수록 screw-in force가 많이 발생하는 것으로 보여지며, 따라서 기구조작 동안의 screw-in force를 방지 또는 억제하기 위해서는 만곡도가 작은 근관을 성형할 때 더 많은 주의가 요구될 것으로 생각된다.

• Restorative Dentistry and Endodontics
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• 제34권3호
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• pp.232-239
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• 2009

본 실험은 발거 된 하악 대구치의 근심 근관을 스테인레스 강 K 파일과 니켈 티타늄 전동식 파일로 근관 성형했을 때 anticurvature filing 방법의 효용성을 평가하고자 했다. 30개의 발거된 하악 대구치 60개의 근심근관을 성형 방법과 기구에 따라 3개의 군으로 나누고 근단부 근관을 30번 크기로 일정하게 확대하였다. 1군은 스테인레스 강 K 파일을 사용해 circumferential filing technique을, 2군은 스테인레스 강 K 파일을 사용해 anticurvature filing technique을 3군은 니켈 티타늄 ProFile 06 series를 사용해 anticurvature filing technique으로 근관을 성형하였다. MCT를 이용해 얻은 술전, 술후 절단면 상을 중첩해 치근단 공에서 1mm 떨어진 지점에서부터 0.5mm 간격으로 위험부위 (danger zone)의 삭제량을 비교하였다. micro-computed tomography system (skyscan-1076, SKYSCAN, Antwerpen, Belgium)을 이용해 얻은 술전 술후 절단면 상을 중첩해 치근단 공에서 1mm떨어진 지점에서부터 0.5mm 간격으로 위험부위 (danger zone)의 삭제량을 비교하였다. danger Bone 폭경의 변화량은 one-way ANOVA를 이용하여 유의성 검정을 하였고 Tukey test를 이용하여 사후검정 하였다. 그 결과, 스테인레스 강 파일을 사용한 경우 circumferential filing으로 근관 성형한 것보다, anticurvature filing으로 근관 성형한 경우가 치관부 1/3부위($7.5{\sim}8.5mm$)의 danger zone의 삭제량이 유의성 있게 적었고 (P<0.05), 니켈 티타늄을 사용하여 anticurvature filing으로 근관 성형한 경우는 danger zone의 중간 1/3부위 ($3.5{\sim}6mm$)의 삭제량이 유의성 있게 적었다 (P<0.05). 니켈티타늄을 사용하여 anticurvature filing으로 근관 성형한 경우, 스테인레스 강 파일을 사용하여 anticurvature filing으로 근관 성형한 경우보다 $3.5{\sim}6mm$의 삭제량이 유의성 있게 적었다 (P<0.05).

• Restorative Dentistry and Endodontics
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• 제31권2호
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• pp.113-118
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• 2006

본 연구의 목적은 새로 시판된 NRT 기구의 근관 형태 유지 능력을 기존의 3종의 기구와 비교하는 것이다. 만곡된 레진 모형 근관을 ProFile, K3, ProTaper, NRT 기구를 이용하여 형성하였고 형성 전, 후의 상을 스캔한 후 중첩시켜 이미지 분석 프로그램을 이용하여 근관 만곡도의 변화와 근관 중심축에 대한 근관의 변이 정도를 근관 중심율의 변화로 계산하여 분석하였다. 근관 변이의 유의성 검정을 위해 one-way ANOVA분석을 시행하였으며 각 기구간의 유의성 검정은 Duncan's test로 사후 분석하였다. 근첨에서 1, 2 mm 상방 위치에서의 근관 중심율은 ProFile 군이 다른 군에 비해 우수한 것으로 나타났다. (p < 0.05). NRT기구의 근관 중심율 변화를 측정한 결과 근첨으로부터 5 mm 상방에서는 Profile에 비해서만 큰 것으로 나타났고 6, 7 mm 상방에서는 다른 모든 군들에 비해 큰 것으로 나타났다 (p < 0.05). 비록 NRT기구가 근첨 부위에서는 ProFile을 제외한 다른 기구에 비해 유의차 없는 중심률 유지 능력을 보였으나 근관 입구 및 중간부위의 형성에 사용되는 스테인레스-스틸 파일로 인해 coronal flaring시 다른 기구들에 비해 더 많은 중심률의 변화를 보이는 것으로 사료된다.

• Restorative Dentistry and Endodontics
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• 제44권4호
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• pp.36.1-36.6
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• 2019

Objectives: The aim of this study was to compare the cyclic fatigue resistance of the WaveOne Gold Glider, ProGlider and One G glide path instruments in artificial doublecurvature canals. Materials and Methods: This study included 15 WaveOne Gold Glider (size 15/0.08), 15 ProGlider (size 16/0.08), and 15 One G (size 16/0.06) nickel titanium files. The files were used in accordance with the manufacturer's instructions until they were broken in artificial double-curvature canals made of stainless steel. The time to fracture was recorded via a digital stopwatch and the number of rotations until fracture was also calculated. The data were statistically analyzed via the Kruskal-Wallis test. Results: The highest average number of rotations until fracture of the files was found for the WaveOne Gold Glider, followed by ProGlider and One G in order. Statistically significant differences were present between all groups of files (p < 0.05). Conclusions: In our study, the resistance of the WaveOne Gold Glider nickel-titanium (Ni-Ti) file to cyclic fatigue in S-shaped curved canals was found to be higher than that of the ProGlider and One G Ni-Ti files.

• Restorative Dentistry and Endodontics
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• 제45권4호
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• pp.51.1-51.10
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• 2020

Objectives: No studies have yet assessed vibration characteristics according to endodontic file length. Accordingly, the objective of the present study was to examine the vibration characteristics according to nickel-titanium file length and to compare these characteristics between different file systems. Materials and Methods: A total of 45 root canal models were divided into 3 experimental groups (n = 15 each) based on the file system used (ProTaper Gold [PTG], ProTaper Next, or WaveOne Gold [WOG]). Each experimental group was further divided into 3 subgroups according to file length (21, 25, or 31 mm). An electric motor (X-SMART PLUS) was used in the experiment. For each file system, vibrations generated when using a size 25 file were measured and used to calculate the average vibration acceleration. The differences in vibrations were analyzed using 1-way analysis of variance and the Scheffé post hoc test with a confidence interval of 95%. Results: In the PTG file system, significantly lower vibration acceleration was observed when using a 21-mm file than when using a 31-mm file. In the WOG file system, significantly stronger vibration acceleration was observed when using a 31-mm file than when using 21- or 25-mm files. Regardless of the file length, the WOG group exhibited significantly stronger vibration acceleration than the other 2 experimental groups. Conclusions: In clinical practice, choosing a file with the shortest length possible could help reduce vibrations. Additionally, consideration should be given to vibrations that could be generated when using WOG files with reciprocating motion.

• Restorative Dentistry and Endodontics
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• 제26권5호
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• pp.418-435
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• 2001

Root canal preparation process is of utmost importance in successful treatment of root canal. Also, one of the most important purpose of the root canal preparation is to enlarge the root canal three dimensionally without changing the curvature of the root canal However as the curvature of the root canal increases, there are many difficulties involved in formation of optimum root canal. Therefore in order to solve the above mentioned problems, new developments in methods of root canal preparation and equipments for such purposes were made. Recently, vigorous studies about newly introduced engine-driven nickel-ti-tanium rotary file are conducted. As shown in research results to dates, it is well established that the use of nickel-titanium file is better suited for curved root canal than stainless steel file in maintaining the curvature or root canal and reducing the deformation of root canal. However it is also acknowledged that there are a few discrepancies in research results according to protocol, due to failure to remove variables in experiments. In addition, although it is recommended by the manufacturer that the GT rotary file should maintain a low rotational speed of 150~350rpm and 'light pressure' as light as not to break the lead of a pencil, academic studies about the vertical force which is not yet standardized are not sufficiently explored. Therefore, this research devised and utilized a special research equipment to standardize the appropriate range of vertical force for GT rotary file through experiments by breaking of the lead of a pencil as expressed by the manufacturer and to accurately measure factors involved through repeating and recreating the environment of root canal preparation. Forming nine experimental groups by varying the vertical forces (150g. 220g, 300g) and rpm (150rpm, 250rpm, 350rpm), the effects of changing vertical forces and rpm on working efficiency were measured in terms of time expended in root canal preparation by crown-down method using a transparent resin block with 35 degree curvature and GT rotary file (z-test). The following research using this special research equipment that involved nine experimental groups and varying the vertical force for root canal preparation from 300g which is within the normal vertical force range to 700g and 1000g which fall outside the normal rpm range. The results were as follows : 1. Analysis of the experiment results revealed that the time spent in root canal preparation decreased as the vertical forces and rpm increased (p<0.05). Also, the effects of rpm were greater than those of the vertical forces within the normal vertical force range ($\beta$-weight test). 2. Observation of the deformation of GT rotary file revealed that deformation increases in a direct correlation with the vertical force increase and in a reverse correlation with the rpm decrease. In the case of the vertical forces close to the normal range, the probability of GT rotary file deformation were quite different depending on the rpm changes. In the case of greater vertical forces, the occurrences of deformation of the file were more frequent regardless of the rpm changes. 3. Deformation and breakage of file were also commonly observed in the expended time measurement experiments and GT rotary file deformation experiments in which low speed rpm (150rpm) was used and at the curved portion of the resin block.