• Restorative Dentistry and Endodontics
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• 제32권6호
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• pp.491-497
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• 2007

이 연구의 목적은 continuous wave of obturation technique으로 근관 충전을 할 때, 다양한 heat source plugger의 깊이에 따른 근단부 근관 폐쇄능력을 비교하는 것이었다. 직선 형태 발거 소구치를 #35/.06 크기까지 니켈티타늄 파일을 사용하여 성형 및 세정하였다. 성형과 세정이 완료된 치아를 heat source plugger의 적용 깊이에 따라 15개씩 5군으로 분류하였다. 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 양성 대조군을 제외한 모든 근관은 E&Q plus(Meta Biomed Co., Chungju, Korea)를 사용하여 #35/.06 gutta-percha cone으로 충전하였다. 모든 치아의 근첨공 주변 1 mm를 제외하고 nail varnish를 도포하였고 음성 대조군은 근첨공을 포함하여 전체 면을 도포하였다. 모든 시편을 1% 메틸렌블루 용액에 72시간 동안 보관한 다음 치근첨으로부터 1, 2, 3 mm 높이에서 수평으로 절단하였다. 각 단면을 $12.5{\times}2.5$배 현미경하에서 관찰하고 디지털 카메라로 촬영하였다. 염색제 누출 평가를 위해 aye-degree scoring system을 사용하였다. 각 절단면에서의 점수를 모두 합하여 한 시편의 점수로 사용하고 통계학적 분석을 하였다. 이 실험 조건하에서, 3-7 mm까지의 heat source plugger의 적용 깊이는 근단부 폐쇄에서 유의한 차이를 나타내지 않았다. 5-7 mm의 Buchanan's protocol을 포함한 3-7 mm를 모두 임상 적용에서 받아들여질 만하다고 보인다.

• Restorative Dentistry and Endodontics
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• 제8권1호
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• pp.161-166
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• 1982

The purpose of this study was to examine the influence of canal preparation on the property of apical seal. Seventy canals from extracted human maxillary and mandibular teeth were randomly selected and divided into two groups: conventional group and step-back group. Thirty five canals in one group were enlarged with a, conventional preparation method and thirty five canals in the other group were instrumented in a step-back method with K-file. After instrumentation sixty canals were obturated by lateral condensation of gutta percha and zinc oxide eugenol cement, and five canals in each group were not filled and used as control. All the specimens were immersed in 2% methylene blue dye solution and the depth of dye penetration into the canals were observed by macroscope at the intervals of 1 day, 2 days, and 7 days. The following results were obtained. 1. All the canals experimented showed varying degrees of dye penetration. 2. There was no significant difference between conventional method and step-back method in the depth of dye penetration and the degree of dye penetration tended to increase with time passage in both groups. 3, In conventional preparation group the mean dye penetration was 3.6mm at 1 day, 4.8mm at 2 days. and 6.5mm at 7 days. 4. In step-back prepareation group, the specimens exposed to the dye for 1 day showed mean dye penetration of 4.1mm, and the specimens immersed in the dye for 2 days and 7 days revealed mean dye penetration of 4.6mm and 6.2mm respectively.

• Restorative Dentistry and Endodontics
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• 제41권2호
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• pp.114-120
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• 2016

Objectives: The aim of this study was to compare the push-out bond strength and dentinal tubule penetration of root canal sealers used with coated core materials and conventional gutta-percha. Materials and Methods: A total of 72 single-rooted human mandibular incisors were instrumented with NiTi rotary files with irrigation of 2.5% NaOCl. The smear layer was removed with 17% ethylenediaminetetraacetic acid (EDTA). Specimens were assigned into four groups according to the obturation system: Group 1, EndoRez (Ultradent Product Inc.); Group 2, Activ GP (Brasseler); Group 3, SmartSeal (DFRP Ltd. Villa Farm); Group 4, AH 26 (Dentsply de Trey)/gutta-percha (GP). For push-out bond strength measurement, two horizontal slices were obtained from each specimen (n = 20). To compare dentinal tubule penetration, remaining 32 roots assigned to 4 groups as above were obturated with 0.1% Rhodamine B labeled sealers. One horizontal slice was obtained from the middle third of each specimen (n = 8) and scanned under confocal laser scanning electron microscope. Tubule penetration area, depth, and percentage were measured. Kruskall-Wallis test was used for statistical analysis. Results: EndoRez showed significantly lower push-out bond strength than the others (p < 0.05). No significant difference was found amongst the groups in terms of percentage of sealer penetration. SmartSeal showed the least penetration than the others (p < 0.05). Conclusions: The bond strength and sealer penetration of resin-and glass ionomer-based sealers used with coated core was not superior to resin-based sealer used with conventional GP. Dentinal tubule penetration has limited effect on bond strength. The use of conventional GP with sealer seems to be sufficient in terms of push-out bond strength.

• Restorative Dentistry and Endodontics
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• 제15권1호
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• pp.81-87
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• 1990

The purpose of this study was to evaluate the apical seal produced by low temperature($70^{\circ}C$) injection gutta percha technique(ULTRAFIL) with & without sealer, warm latero-vertical cindensation technique (ENDOTEC) with & without sealer, and the lateral condensation technique with sealer. 100 extracted, single rooted human teeth were divided into 5 groups and root canals were enlarged & obturated according to the purpose of this study. Obturated teeth were immersed in 2.5% methylene blue for 48hrs. at $37^{\circ}C$ incubator and split. The apical sealing ability was evaluated by measuring the degree of dye penetration into the canal. The results were as follows: 1. All group showed varying depth of dye penetration. 2. There were no significant difference among Group I (lateral condensation), Group II (ULTRAFIL with sealer) & Group IV (ENDOTEC with sealer) (P>0.05). 3. There were less dye penetration when used in conjunction with sealer (P<0.001).

• Restorative Dentistry and Endodontics
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• 제33권2호
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• pp.107-114
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• 2008

본 실험에서는 다양한 방사선 노출 조건에 따른 aluminum step wedge에 대한 광학 밀도를 알아보고, 그 중 적절한 노출조건을 선택하여 수종의 근관 충전재와 치근단 역충전재의 방사선 불투과성 정도를 평가, 비교하였다. 방사선 불투과성의 기준을 위해 11개의 step으로 구성된 aluminum step wedge를 제작하여, 60 kVp, 70 kVp 관전압 상태에서 각각 0.2, 0.,3, 0.4초와 0.2, 0.3, 0.33초의 노출시간으로 교합 필름상에서 방사선 촬영 후 적절한 노출조건을 구하였다. 직경 5 mm, 각각의 두께 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 mm인 10종 (Gutta-percha, amalgam, Super $EBA^{(R)}$, MTA, $IRM^{(R)}$, Fuji II LC, $Dyract^{(R)}$ AP AH, $26^{(R)}$, $Sealapex^{TM}$, Tubli-$Seal^{TM}$)의 근관 충전재와 치근단 역충전재 시편을 각 재료와 두께당 10개씩 제작한 후, 동일한 두께의 상아질 시편, aluminum step wedge와 함께 정해진 노출조건에 따라 방사선 촬영을 하였다. 모든 필름은 자동현상기로 현상하였다. 시편의 흑화도를 densitometer (Model 07-443, Victoreen Inc, Cleveland, Ohio, USA)로 5회 반복 측정 후, 평균값을 구하여 회귀분석 후 알루미늄 두께로 환산하였다. 얻어진 정보를 분석하여 다음의 결과를 얻었다. 1. 관전압 60 kVp에서 노출시간 0.2, 0.3, 0.4초, 70 kVp에서 0.2, 0.3. 0.33초로 변화를 주어 방사선 촬영을 하였을 때, 흑화도가 0.5-2.5 사이여야 한다는 ISO No. 6876 규격에 가장 적합한 것은 60 kVp, 0.2초일 경우였다. 2. 측정된 근관 충전재와 치근단 역충전재들의 방사선 불투과성 모두 ISO No.4049 규격에 적합하였다. 3. 광중합형 글래스 아이오노머 (Fuji II LC)와 컴포머 (Dyract)를 제외하고는 ANSI/ADA specification (2000) 또는 ISO No. 6876 (2001)규격이 제시한 최소한 3 mm Al 이상의 방사선 불투과성을 지녀야 한다는 규격에 적합하였다. 이상의 결과는 본 실험에 사용된 수종의 근관 충전재와 치근단 역충전재 중 Fuji II LC와 Dyract를 제외하고 모두 규격에 적합한 방사선 불투과성을 가지고 있음을 시사한다.

• Restorative Dentistry and Endodontics
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• 제10권1호
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• pp.115-126
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• 1984

The purpose of this study was to determine the incidence and the degree of interappointment pain and post obturation pain associated with the pretreated clinical factors or conditions, and to examine the correlation between the success or failure and the pretreated clinical factors or conditions and postoperative pain. The author experienced the conventional root canal therapy in one hundred fifty-one teeth after recording the following clinical factors or conditions - sex, age, pulp vitality status, presence or absence of periapical rarefaction, single or multirooted teeth, pretreatment pain, and investigated the pain during and after treatment for seven days. After six months all the cases were re-evaluated through the clinical sign, symptom, and the recalled radiograph. The following results were obtained; 1. Of the 151 teeth (73.5%) had no interappointment pain, 31 teeth (20.5%) slight pain; and 9 teeth (6.0%) moderate to severe pain. 2. The presence of the pretreatment pain significantly increased the incidence and degree of interappointment, and there were no significant relationship between interappointment pain and other clinical factors or conditions. 3. Of the 151 teeth, 142 teeth (4.0%) experienced no post obturation pain, 3 teeth (2.0%) slight pain, 6 teeth (4.0%) moderate to severe pain. 4. There were no statistical correlation between postobturation pain and any of the clinical factor or conditions. 5. 141 teeth (3.4%) of 151 teeth were evaluated as success in this study, and success rate was decreased significantly in the cases of periapical rarefaction before treatment and postobturation pain. But there were no significant relationship between success or failure and other clinical factors or conditions.

• Restorative Dentistry and Endodontics
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• 제48권2호
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• pp.15.1-15.7
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• 2023

Objectives: This study evaluated the efficiency of WaveOne Primary files (Dentsply Sirona) for removing root canal fillings with 2 types of movement: reciprocating (RCP) and continuous counterclockwise rotation (CCR). Materials and Methods: Twenty mandibular incisors were prepared with a RCP instrument (25.08) and filled using the Tagger hybrid obturation technique. The teeth were retreated with a WaveOne Primary file and randomly allocated to 2 experimental retreatment groups (n = 10) according to movement type: RCP and CCR. The root canals were emptied of filling material in the first 3 steps of insertion, until reaching the working length. The timing of retreatment and procedure errors were recorded for all samples. The specimens were scanned before and after the retreatment procedure with micro-computed tomography to calculate the percentage and volume (mm³) of the residual filling material. The results were statistically evaluated using paired and independent t-tests, with a significance level set at 5%. Results: No significant difference was found in the timing of filling removal between the groups, with a mean of 322 seconds (RCP) and 327 seconds (CCR) (p < 0.05). There were 6 instrument fractures: 1 in a RCP motion file and 5 in continuous rotation files. The volumes of residual filling material were similar (9.94% for RCP and 15.94% for CCR; p > 0.05). Conclusions: The WaveOne Primary files used in retreatment performed similarly in both RCP and CCR movements. Neither movement type completely removed the obturation material, but the RCP movement provided greater safety.

• Restorative Dentistry and Endodontics
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• 제32권6호
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• pp.522-529
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• 2007

최근 continuous wave of obturation technique을 이용한 근관 충전 장비로서 열 적용뿐 만 아니라 초음파 진동의 기능이 부가된 EndoTwinn이라는 기구가 소개되었다. 이 연구의 목적은 일반적으로 널리 사용되는 System B와 새로운 기구인 EndoTwinn을 사용한 근관충전 시 근단 폐쇄 효율을 비교하기 위한 것이다. 직선형 치근을 가진 60개의 발치된 소구치와 상악 절치를 근관장 측정 후, 6% 경사의 엔진 구동형 니켈-타이타늄 파일을 이용하여 #35 파일까지 확대 및 세척하였다. SB군 (n=20)은 System B, ET군 (n=20)은 EndoTwinn을 이용해 충전하고, Obtura II를 이용하여 backfill하였다. 양성 대조군으로서 PC군(n=10)은 근관 형성 후 빈 근관으로 남겨두었다. SB, ET, PC군의 시편은 치근첨 주위 1 mm를 제외한 모든 치근면에 nail varnish을 적용하고 음성 대조군인 NSB군(n=5)과 NET군(n=5)의 시편은 치근첨을 포함한 모든 치근면에 nail varnish를 도포하였다. 각 치아의 치근첨을 메틸렌블루 용액에 2일간 담궈 보관한 후, 치근첨에서 5 mm까지 1 mm간격으로 절단하여 근관벽의 착색 정도를 평가하였고, 각 높이에서의 점수를 합하여 그 시편의 점수로 정하였다. 두 장비 간의 염색제 누출의 유의성 검정을 위해 student t 분석을 시행하였다. 완전히 잘려지지 않고 플러거에 가타퍼챠가 달려나오는 빈도를 비교하기 위해 카이 분석을 시행하였다. PC군은 모든 근관과 상아세관이 착색되었으며, NC군은 착색이 되지 않았다. ET군의 착색 정도가 SB군보다 유의하게 적게 나타났으며(p < 0.05). 플러거에 가타펴챠가 달려나오는 빈도는 유의한 차이가 없었다. 이 실험의 조건하에서, EndoTwinn을 이용해 충전한 경우에 System B를 이용해 충전한 경우보다 근단부 밀폐 정도가 더 좋은 것으로 사료된다.

• Restorative Dentistry and Endodontics
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• 제25권4호
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• pp.527-535
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• 2000

The purpose of this study was to evaluate effects of smear layer and dentin primers on the sealing ability of root canals. 126 extracted human teeth with single, straight canals and mature apices were used. The Samples were first classified into six groups as follows: presence of smear layer; absence of smear layer; Scotchbond Bond Multi-Purpose; All Bond 2; Mac Bond 2; Clearfil Liner Bond 2. A Positive control was also established. All teeth except the control group were then obturated with thermoplasticized gutta-percha and AH26. Electrochemical and dye penetration technique were later used to evaluate the degree of micro leakage through the root canal. Seventy teeth were then immersed in a 1% potassium chloride solution and An external power supply(DC 10 V) was then applied to the circuit for the electrochemical microleakage test. The degree of Microleakage was determined over period of 28 days before being evaluated. In total, 48 teeth were submitted to the dye infiltration technique. All specimen were suspended in 2% methylene blue dye for 1 week before being longitudinally split. The degree of dye infiltration was measured under a stereo microscope at ${\times}10$ magnification and evaluated. The results were as follows: 1. Apical microleakage increased throughout the test period in all group and one group having a smear layer showed a dramatic increase under electrochemical test (p<0.05). In the group having smear layer, the degree of apical microleakage was the highest, and the micro leakage was much higher than in the smear layer removed group in electrochemical test (p<0.05). Scotchbond Multi-Purpose, All Bond 2, Mac Bond 2 and Clearfil Liner Bond 2 showed lower micro leakage than one group having smear layer. The All Bond 2 and Clearfil Liner Bond 2 treated groups showed the lowest microleakage in electrochemical test (p<0.05). 2. There was no significant difference between the experimental groups in dye penetration technique. These results suggested that the removal of the smear layer from root canal and concomitantly the application of dentin primer into root canal could improve the sealing ability of root canal obturation.

• Restorative Dentistry and Endodontics
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• 제42권4호
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• pp.273-281
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• 2017

Objectives: The aims of this study were to quantify tug-back by measuring the pulling force and investigate the correlation of clinical tug-back pulling force with in vitro gutta-percha (GP) cone adaptation score using micro-computed tomography (${\mu}CT$). Materials and Methods: Twenty-eight roots from human single-rooted teeth were divided into 2 groups. In the ProTaper Next (PTN) group, root canals were prepared with PTN, and in the ProFile (PF) group, root canals were prepared using PF (n = 14). The degree of tug-back was scored after selecting taper-matched GP cones. A novel method using a spring balance was designed to quantify the tug-back by measuring the pulling force. The correlation between tug-back scores, pulling force, and percentage of the gutta-percha occupied area (pGPOA) within apical 3 mm was investigated using ${\mu}CT$. The data were analyzed using Pearson's correlation analysis, one-way analysis of variance (ANOVA) and Tukey's test. Results: Specimens with a strong tug-back had a mean pulling force of 1.24 N (range, 0.15-1.70 N). This study showed a positive correlation between tug-back score, pulling force, and pGPOA. However, there was no significant difference in these factors between the PTN and PF groups. Regardless of the groups, pGPOA and pulling force were significantly higher in the specimens with a higher tug-back score (p < 0.05). Conclusions: The degree of subjective tug-back was a definitive determinant for master cone adaptation in the root canal. The use of the tug-back scoring system and pulling force allows the interpretation of subjective tug-back in a more objective and quantitative manner.