• Restorative Dentistry and Endodontics
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• 제24권1호
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• pp.222-232
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• 1999

The purpose of this study was to evaluate the effect of heated spreader on the sealing ability of lateral condensation, compared with regular cold spreader. Forty two extracted human teeth with single canal were randomly placed into 3 experimental groups, and four additional teeth were used as positive and negative controls. Each group was prepared with Ni-Ti Profile #40 using step-down technique and obturated with standardized colored gutta-percha cone by standard(cold) lateral condensation technique, warm lateral condensation technique with Endotec and hot spreader soaked in glass bead sterilizer, each with Sealapex sealer. Control groups were not obturated, but prepared. After 2 days in 2% methylene blue, the teeth were invested and made into transparent resin blocks. And then, each block was sectioned horizontally with microtome at 1, 2, 3, 4, 5 mm levels from the apex. The linear extent of dye penetration was examined with stereomicroscope at ${\times}$20 magnification. At each of 5 levels, ratio of the area of gutta-percha was obtained by calculating the area of gutta-percha to the total area of the canal. The data collected were then analyzed statistically using an analysis of variance(ANOVA) and Scheffe test. The results were as follows ; 1. All experimental groups produced the apical microleakage. 2. The mean leakage was 1.57${\pm}$0.76mm for cold spreader group, 0.86${\pm}$0.95mm for Endotec spreader group, and 0.64${\pm}$0.93mm for hot spreader group. The difference between hot spreader group and cold spreader group was statistically significant(p<0.05). 1. At the 1 mm level, the mean ratio of area of gutta-percha was 74.58${\pm}$13.15(%) for cold spreader group, 65.42${\pm}$14.62(%) for Endotec spreader group, and 80.72${\pm}$14.63(%) for hot spreader group. There was statistically significant difference between hot spreader group and Endotec spreader group(p<0.05). 2. At the 2mm level, the mean ratio of area of gutta-percha was 87.86${\pm}$11.22(%) for cold spreader group, 66.55${\pm}$14.02(%) for Endotec spreader group, and 92.93${\pm}$7.24(%) for hot spreader group. There was statistically significant difference between Endotec spreader group and other two spreader groups(p<0.05). 3. At the level 3, 4, 5 mm, there was no statistically significant difference between each group. Within the limits of the results of this experiment, warm lateral condensation technique with hot spreader soaked in a glass bead sterilizer demonstrated favorable apical sealing effect and improved density of gutta-percha mass. Thus, it is thought that this obturation technique is effective for clinical use and beneficial to reduce condensation forces, also economical and easy. Lateral condensation, Heated spreader, canal sealing, Microleakage.

• Restorative Dentistry and Endodontics
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• 제16권2호
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• pp.155-164
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• 1991

The purpose of this study was to evaluate the effects of bleaching agent through the dentinal tubules of cervical area in the intracoronal bleaching of pulpless teeth on cutured fibroblast cells. Extracted human incisors were enlarged to # 40 K-file and obturated with gutta-perella and AH 26 sealer. The gutta-percha was removed to 2mm below the cementoenamel junction of the root The teeth were divided into 3 experimental and control groups. Experimental groups; Experimental group 1: Temporary inlay wax filld with 30% $H_2O_2$ in pulp cavity. Experimental group 2: Temporary inlay wax filld with 30% $H_2O_2$ in pulp cavity after placement of ZOE cement to cementoenamel junction. Experimental group 3: Temporary inlay wax filld with 30% $H_2O_2$ in pulp cavity after application of Copalite to cementoenamel junction. Control group: Temporary inlay wax filled without 30% $H_2O_2$ in pulp cavity under the same condition at each experimental group. Each tooth was immersed in well of multidish cultured fibroblast cell for 48 hours. The cellular multiplication and cell viability were calculated at the interval of 1, 3, 5. 7 hours and the morphological changes in well were observed and their photographs were taken with inverted microscope. The obtained results were as follows : CD The cellurar multiplicaton and cell viability decreased in all experimental groups at 1 hour after experiment and the morphology of fibroblast cell was changed from star shape to round (2) The cell viability was lowered to 34 % in experemental group 1, 44 % in experimental group 2, and 38 % in experemental group 3 at 3 hours after experiment (3) The cell multiplication was decreased to 54% in experemental group 1. 47% in experimental group 2, and 40% in experemental group 3 at 7 hours after experiment. (4) The decrease of cell number and morphological changes of fibroblast cell were remarkable in experimental group 1, group 3 and 2 in order. These results suggest that the fibroblast cells receive severe damage by 30% $H_2O_2$ solution leaked through the dentinal tubules and the dentinal tubules are able to be obturated better by ZOE cement than by Copalite.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2002년도 학술대회지
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• pp.539-542
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• 2002

도로면 유지보수를 시행함에 있어 노면의 파손정도에 따라 다양한 공법의 사용이 가능하나 크랙 실링 공법은 예방적 차원에서 도로면에 발생된 크랙을 초기에 효과적으로 보수할 수 있는 방법이다. 그러나, 교통량이 많은 대도시나 고속도로에서 시행되는 도로면 유지보수 작업의 경우 노무자가 열악한 작업환경 내에서 작업을 수행해야 하므로 안전성 확보에 문제가 있고, 도로면 유지보수 작업의 특성상 현장 노무자의 잦은 이직(labor turnover) 및 3D업종의 기피로 인한 숙련공 부족현상은 현 도로면 유지보수 작업의 생산성 및 품질 저하를 가져오고 있다. 선진 외국의 경우 크랙 실링 공법의 이점 및 도로 유지보수 공사의 위험 요소를 인식하여 자동화 장비의 개발을 통한 안전성, 생산성 향상 및 경제성 확보에 다양한 연구 노력을 기울이고 있으나, 국내의 경우 도로면 유지보수 공사를 위한 기술축적이나 자동화 장비 개발을 위한 시도는 매우 미약한 실정이다. 따라서, 본 연구에서는 도로면 유지보수 공법 중 크랙 실링 공법의 자동화를 통해 노무자의 안전사고를 방지하고, 품질 및 생산성 향상을 도모할 수 있는 크랙 실링 자동화 방안을 제시하고자 한다.

• 대한토목학회논문집
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• 제34권4호
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• pp.1289-1298
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• 2014

도로면 크랙실링 공법은 균열발생 초기에 도로면을 보수하여 균열의 확산을 예방하는 유지보수공법으로써 북미를 중심으로 한 선진 외국에서는 이미 오래전부터 많은 도로 보수 물량에 적용되어 왔다. 그러나 재래식 크랙실링 공법은 작업 특성상 교통량이 많은 일반도로나 고속국도에서 작업이 수행되므로 교통사고가 빈번하게 발생하고, 가열된 실런트를 도로면에 직접 분사하기 때문에 화상의 위험으로부터 노무자의 안전을 확보하기 어려운 문제점이 있다. 이러한 문제점을 해결하기 위하여 선진 외국에서는 1990년대 초부터 ARMM, OCCSM, TTLS 등의 크랙실링 자동화 장비를 지속적으로 연구 개발해 왔으며, 국내에서도 2004년 APCS 장비와 2013년 ACSTM 장비를 개발 완료한 바 있다. 그러나 다수의 연구기관에서 서로 상이한 시기에 개발된 크랙실링 자동화 장비는 각기 다른 테스트베드 조건과 생산성 측정 방법을 사용하여 개발 장비의 작업 생산성을 측정, 표기함으로써 각 크랙실링 자동화 장비의 성능을 객관적으로 비교, 평가할 수 없는 문제점이 있었다. 이 연구에서는 동일한 환경 조건 내에서 크랙실링 자동화 장비의 생산성을 측정하기 위해 완전자동 맵핑 및 반자동 맵핑 방식에 따른 각 크랙실링 자동화 장비의 이미지 프로세싱 소요시간을 추정하고, 작업 프로세스상의 동작요소별 이동시간을 산정하였다. 또한 국내 도로환경이 반영된 생산성 측정 테스트베드를 설계하였으며, 이를 기반으로 국내외에서 개발된 크랙실링 자동화 장비의 생산성을 동일한 조건 내에서 측정하고 상호 비교, 분석하였다.

• 한국가정과학회지
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• 제7권1호
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• pp.33-41
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• 2004

The purpose of the study was to analyze in process of circulation market boiled whale meat's rancidity. oxidative rancidity is oil or fat food depend on oxygen in air oxidative change in quality. boiled whale meat faty come to oxidative rancidity food stability and hygiene reasons for people health poisonous point out, however it is not indication study of support. Accordingly confirm lead into circulation process boiled whale meat's rancidity examination and microorganism examination boiled whale meat's stability whether or not. The result obtained were summarized as follows: 1. Proximate percentage of boiled whale meat(pectoral, pelvic, fin, flank) of moisture and crude lipid and crude protein from samples shown to be : moisture was pectoral 16.4%, pelvic 36.2%, fin 46.2%, flank 19.2%, crude lipid was pectoral 54.1%, pelvic 42.8%, fin 15.8%, flank 40.6%,crude protein was pectoral 29.4%, pelvic 20.5%, fin 29.5%, flank 28.6%. 2. The fatty acid composition of total lipid were composed of pectoral 27.2%, pelvic 28.9%, fin 33.3%, flank 23.4% of oleic acid and pectoral 12.7%, pelvic 11.1%, fin 11.3%, flank 14.0% of palmitic acid pectoral 10.8%, pelvic 7.9%, fin 7.6%, flank 2.1% of docosahexaenoic acid, pectoral 14.2%, pelvic 7.5%, fin 1.9%, flank 7.2% of eicosenoic acid, pectoral 5.1%, pelvic 5.7%, fin 4.4%, flank 5.7% of myristic acid, 16: 0 11∼14 % of high saturated fatty acid. generally most of 18: 1ω9 of boiled whale meat's each portion, 22:6 7∼12%, 20:5 1∼14% of polyenoic fatty acid. 18:3 showen to be 1% make an expection of pectoral and fin portion the total lipid were most of netural lipid's about 90%, monoenic fatty acid were most of 19∼22% of saturated fatty acid, 77∼80% of monoenic fatty acid level of 47∼56% of 18:1 16:1 was markelly high to those of total lipid. 3. The storage number days variation of oxidation were shown to be by stages process favorably the past days of boiled whale meat's acid value for 5days. pectoral the day 0.1, five days 1.3, pelvic the day 0.1, five days 1.6, fin the day 0.3, five days 0.7, flank the day 0.2, five days 0.4. 4. The sealer and wrapper the storage number days variation of boiled whale meat oxidation for 7days were shown to be a stage of sealing, the temperature of a room, pectoral the day 0.1 seven days 0.6, pelvic the day 0.1, seven days 1.3, fin.

• Restorative Dentistry and Endodontics
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• 제25권3호
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• pp.381-389
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• 2000

Lateral condensation with gutta-percha and sealer has been shown to provide an excellent apical seal; however, the lateral condensation technique has demonstrated less favorable apical leakage results in curved canals when compared with straight canals. Placement of endodontic spreaders to within 1 to 2mm of the root canal working length has been advocated for optimum gutta-percha obturation. Due to their stiffness, stainless-steel(SS) spreaders will often fail to achieve this position in curved canals. Newly marketed nickel-titanium(NT) spreaders may offer an advantage in this regard due to the increased flexibility of these instruments. The purpose of this study was to evaluate the effect of NT finger spreader on the sealing ability in lateral condensation technique, compared with conventional SS finger spreader. Twenty four standardized resin models simulating curved canals(30 degree) were randomly placed into 2 groups and instrumented to a #30 master apical file size with Ni-Ti Profile .04 taper series using step down technique. Each groups was obturated with standardized gutta-percha cone by standard lateral condensation technique using SS finger spreader, NT finger spreader. And then, each model was sectioned horizontally with microtome at 1, 2, 3, 4, 5mm levels from the apex. At each of 5 levels, ratio of the area of gutta-percha was obtained by calculating the area of gutta-percha to the total area of the canal. The data collected were then analyzed statistically using a t test for independent samples. The results as follows ; 1. The total mean ratio of area of gutta-percha was 89.20${\pm}$7.00(%) for SS spreader group. 92.20${\pm}$5.17(%) for NT spreader group. There was statistically significant difference between each group(p<0.05). 2. At 3mm level, the mean ratio of area of gutta-percha was 88.32${\pm}$5.41(%) for SS spreader group, 95.25${\pm}$2.60(%) for NT spreader group. There was statistically significant difference between each group(p<0.05). At 1,2,4mm levels, NT spreader group showed greater mean ratio of area of gutta-percha than SS spreader group, too. But there was no statistically significant difference. 3. At 5mm level, the mean ratio of area of gutta-percha was 91.83${\pm}$3.42(%) for SS spreader group, 87.91${\pm}$3.68(%) for NT spreader group. There was statistically significant difference between each group(p<0.05). This study concluded that the NT spreader demonstrated somewhat favorable apical sealing effect than SS spreader in prepared curved canals. The clinical use of NT spreaders may enhance our ability to create better apical seals in curved canals, but further studies in this area will help clarify some of the remaining areas with which practitioners are concerned, such as compaction forces exerted by NT spreaders.

• 대한치과교정학회지
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• 제20권3호
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• pp.447-462
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• 1990

The objective of this experiment is to observe structural differences in the othodontic movement of vital (control group) and devitalized (experimental group) teeth in the mongrel dogs. The 5 utilized dogs in this experiment were approximately 1 year of age and their average weight was about 12 Kg. Endodontic therapy was performed on the 2nd premolars in upper & lower jaws of each animal under the general anesthesia by intravascular injection of 25mg/kg of pentobarbital sodium. The canals of the teeth were obturated by using gutta percha in conjunction with root canal sealer (AH26 Densply). One of the roots in the 2nd premolars was hemisected to make an extraction space for the devitalized teeth to be moved. The edgewise technique was employed for the movement of the teeth. Orthodontic models and intraoral roentgenograms were taken before and after orthodontic tooth movement. The open coil springs (.010 x .040) were used at interbraket space in order to provide equal forces (75gm) between the teeth in each arch wire. After 13 weeks of active orthodontic tooth movement, dogs were sacrified and the experimental results w ere examined through the intraoral radiography, microscopic examination and scanning electromicroscopic examination at the root sulfate. From the results of the study, the following conclusions may be drawn: The root resolution and cemental deposition were observed within the pressure and tension site in both group. 2. The root resorbed lacunae were observed in the cementum and/or into the dentin in both group. 3. The prominent osteoblastic activities were observed on the alveolar margin in the tension site in both group. 4. A few of blood vessels were observed in the pressure site, but also lots of blood vessels were observed in the tension site especially in the periphery of the alveolar bone in both group. 5. In the pressure site, resorbed lacunae were formed with deep and narrow cavity in the control group; the shallow and wide cavity in the experimental group. 6. In the pressure site, the repaired cementum or cementoid tissue was lined on cementum in the experimental group, but not in the control group. 7. There was no significant difference between external root resolution of endodontically and vital teeth when both were subjected to orthodontic forces.

• Journal of Oral Medicine and Pain
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• 제36권3호
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• pp.199-205
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• 2011

근관치료 중 수동 또는 엔진구동파일을 사용하다 과도한 기구 조작을 하게 되면, 근관충전제, 드레싱제 그리고 근관세척제가 근관에서 나와 하악관으로 확산될 수 있다. 이 때 환자는 통증, 지각과민, 지각감퇴, 무감각, 이상감각 등을 호소하게 될 것이다. 이런 문제들은 근관충전제에 포함되어 있으면서 생체적합성이 떨어지는 물질들에 의한 비가역적인 손상을 피하기 위해 가능한 빨리 해결되어야 한다. 비록 근관치료와 관련하여 발생한 하치조신경의 손상을 치료하는 진료지침이 비교연구 되어 있는 것이 없으나, 이 합병증에 대한 통상의 치료는 통증과 염증을 조절하는 것이고, 가능하다면 수술적인 치료로 근원을 처치하는 것이다. 그러나, 비수술적인 치료로 통증을 완전히 개선하거나 감소시키고 또는 감각이상을 치료하는 것이 보고되어왔다. 가바펜틴(gabapentin) 또는 프리가발린(pregabalin) 같은 항간질제는 신경병증 통증의 치료에 이용되어 왔다. 이번 논문에서는 하악 우측 제 2대구치의 근관치료 후의 하치조신경의 손상과 이에 대해 프레드니솔론과 가바펜틴으로 비외과적 치료를 시행한 것과 임상적으로 신경감각검사와 신경전류인지역치검사(Neurometer)를 통해 경과관찰을 시행하였다.

• Imaging Science in Dentistry
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• 제48권1호
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• pp.11-19
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• 2018

Purpose: This study compared the diagnostic accuracy of cone-beam computed tomography (CBCT) scans obtained with 2 CBCT systems with high- and low-resolution modes for the detection of root perforations in endodontically treated mandibular molars. Materials and Methods: The root canals of 72 mandibular molars were cleaned and shaped. Perforations measuring 0.2, 0.3, and 0.4 mm in diameter were created at the furcation area of 48 roots, simulating strip perforations, or on the external surfaces of 48 roots, simulating root perforations. Forty-eight roots remained intact(control group). The roots were filled using gutta-percha (Gapadent, Tianjin, China) and AH26 sealer (Dentsply Maillefer, Ballaigues, Switzerland). The CBCT scans were obtained using the NewTom 3G (QR srl, Verona, Italy) and Cranex 3D (Soredex, Helsinki, Finland) CBCT systems in high- and low-resolution modes, and were evaluated by 2 observers. The chi-square test was used to assess the nominal variables. Results: In strip perforations, the accuracies of low- and high-resolution modes were 75% and 83% for NewTom 3G and 67% and 69% for Cranex 3D. In root perforations, the accuracies of low- and high-resolution modes were 79% and 83% for NewTom 3G and was 56% and 73% for Cranex 3D. Conclusion: The accuracy of the 2 CBCT systems was different for the detection of strip and root perforations. The Cranex 3D had non-significantly higher accuracy than the NewTom 3G. In both scanners, the high-resolution mode yielded significantly higher accuracy than the low-resolution mode. The diagnostic accuracy of CBCT scans was not affected by the perforation diameter.

• 한국건설관리학회논문집
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• 제5권2호
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• pp.162-171
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• 2004

도로면 유지보수를 시행함에 있어 노면의 파손정도에 따라 다양한 공법의 사용이 가능하나 크랙실링 공법은 예방적 차원에서 도로면에 발생된 크랙을 초기에 효과적으로 보수할 수 있는 방법이다. 그러나 교통량이 많은 대도시나 고속도로에서 시행되는 도로면 유지보수 작업의 경우 노무자가 열악한 작업환경 내에서 작업을 수행해야 하므로 안전성 확보에 문제가 있는 것으로 분석되었다. 또한, 도로면 유지보수 작업의 특성상 현장 노무자의 잦은 이직(labor turnover) 및 3D업종의 기피로 인한 숙련공 부족현상은 현 도로면 유지보수 작업의 생산성 및 품질 저하를 가져오고 있다. 선진 외국의 경우 크랙실링 공법의 이점 및 도로 유지보수 공사의 위험 요소를 인식하여 자동화 장비의 개발을 통해 안전성 및 생산성 향상, 경제성 확보에 다양한 연구 노력을 기울이고 있으나 국내의 경우 도로면 유지보수 공사를 위한 기술축적이나 자동화 장비 개발을 위한 시도는 매우 미약한 실정이다. 따라서, 본 연구에서는 도로면 유지보수 공법 중 크랙실링 공법의 자동화를 통해 노무자의 안전사고를 방지하고, 품질 및 생산성 향상을 도모할 수 있는 크랙실링 자동화 장비의 프로토타입을 개발하고자 한다.