• Restorative Dentistry and Endodontics
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• 제21권1호
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• pp.202-217
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• 1996

The purpose of this study was to compare the degree of microleakage of Glass-Ionomer root canal sealer possessed several enviable properties with that of the other sealers and to evaluate clinical performance. One hundred twenty single-rooted teeth were used in this experiment. The teeth were cleaned mechanically and immersed for 24 hours in 5.25% sodium hypochlorite and clinical crowns then were removed. After the root canals were instrumented using a step-back technique. one hundred twenty single-rooted teeth were divided into five groups of 24 in each. Group 1 : Tubli-Seal(Kerr Co., MI, U.S.A/ZOE-based), lateral condensation Group 2 : Sealapex(Kerr/Sybron, Romulus, MI/ $Ca(OH)_2$-based), lateral condensation Group 3 : AH 26(De Trey Co., Zurich Switzerland/Resin-based), lateral condensation Group 4 : Ketac-Endo(ESPE GMBH & CO. KG Seefeld:oberbay. Germany/ Glass Ionomer Cement-based), lateral condensation Control group : no sealer. lateral condensation And then. the root canals were obturated by lateral condensation technique with gutta-percha and experimental sealers. The control group were obturated without sealer. The teeth were placed in a vacuum chamber for 15 minutes and immersed 2% methylene blue under vacuum for 15 minutes. The teeth were passively stained for 1 week and 2 weeks and were cleared and evaluated for linear dye leakage using Tool maker's microscope(${\times}200$). The results were as follows: 1. There were statistically significant differences in the degree of dye penetration between the control group and experimental groups(p<0.05). 2. In the experimental groups, Sealapex($1.2871{\pm}0.9180mm$) exhibited the lowest mean value of dye penetration, followed by Ketac-Endo($1.4432{\pm}0.8082mm$), AH 26($1.5030{\pm}0.7752mm$) and Tubli-Seal($1.6458{\pm}1.0292mm$)(p>0.05). 3. There were statistically significant differences in the variation of microleakage between 1 week and 2weeks in Tubli-Seal and Seal apex groups (p<0.05). 4. The degree of dye penetration of all groups were increased as the time elapsed and AH 26 showed the lowest variation(+0.11) and Tubli-Seal(+ 1.03) showed the highest variation (p<0.001).

• 대한소아치과학회지
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• 제31권1호
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• pp.92-97
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• 2004

청소년기에는 두개악안면부위의 외상성 손상이 흔하다. 그러나 상아질, 백악질, 치수를 포함하는 치아파절로 정의 되는 치근파절을 비교적 드물다. 성장기 아동에 있어서 외상으로 인한 손상은 심리적인 위축감, 안모에 대한 열등감 등의 정서적인 문제와 치조골과 안모의 성장이나 치간 간격의 유지에 영향을 미치는 등의 지장을 초래하기 때문에 보존적인 치료가 요구된다. 첫 번째 증례는 9세의 남아로 상악 우측 중절치의 치수노출을 동반한 치관 파절과 치근단부위에 치근의 수평 파절이 관찰되어 치관부 파절편 치수만 제거하고 수산화칼슘을 이용하여 충전하였다. 6개월 후 방사선 사진에서 dentinal bridge의 형성을 확인할 수 있었고 치근단부는 병적 소견 없이 정상적으로 발육되고 있었다. 1년 3개월 후 방사선 사진에서 치근단부의 형성이 완료된 것을 확인하여 gutta percha를 이용하여 영구 충전을 시행하였다. 두 번째 증례는 7세의 여아로 상악 우측 중절치의 치수 노출을 동반한 치근의 수직 파절이 관찰되어 인위적 발거 후 레진 시멘트를 이용하여 파절편 부착 후 재식하였다. 술 후 8개월 동안의 관찰결과 특이한 임상적 증상은 나타나지 않았다. 이상의 증례에서 치근 파절이 발생한 치아에서 보존적 치료를 시행하였고 이에 양호한 결과를 얻었기에 보고하는 바이다.

• Restorative Dentistry and Endodontics
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• 제19권2호
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• pp.549-567
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• 1994

Restoration of severly damaged teeth after endodontic treatment had been an interest to many dentists, and it is a fact that there have been lots of studies about it. In these days, although we have used Para-Post, pins, threaded steel post, cast gold post and core, and so on, as a method of restoration frequently, it has been in controversy with the influence of them on the teeth and surrounding periodontal tissue. In this study, we assume that the crown of the upper incisor have severly damaged, so, after the root canal therapy, 4 types of restoration had been carried out; 1) coronal-radicular amalgam restoration, 2) after setting up the Para-Post, restore with composite resin core only, 3) after setting up the Para-Post; restore with amalgam core, then cover with the PPM crown 4) after setting up the Para-Post, restore with composite core, then cover with the PPM crown. After restoration, in order to observe the concentration of stress at internal portion of the teeth and the sourrounding periodontal tissue, developing a 2-dimensional finite element model of labiopalatal section, then loading forces from 3 direction - direction of 45 degrees from lingual side near the incisal edge, horizontal direction from labial height of contour, vertical direction at the incisal edge-were applied. The analyzed results were as follows: 1. Stress of the normal central incisor was concentrated on the dentin aroundpulp chamber, labiocervical portion of a tooth and root apex, but with the alveolar bone, in the case of load from the direction of 45 degrees from lingual side near the incisal edge showed remarkable concentration of stress: 2. Coronal-radicular amalgam technique -showed less concentration of stress on the root and surrounding periodontal tissue than the restoration with the Para-Post. 3. The von Mises equivalent stress on the Para-Post showed maximum value at root-core junction rather than both ends and model with PPM restoration with amalgam core showed the least concentration of stress. Only the force from horizontal direction showed large shear stress on internal portion of the root, root apex and alveolar bone. 4. PPM crown with composite core rarely showed the concentration of stress on root and periodontal tissue. 5. As for alveolar bone, remarkable shear stress was concentrated on labial and palatal side by horizontal load.

• 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.

• Restorative Dentistry and Endodontics
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• 제31권2호
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• pp.96-102
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• 2006

본 연구는 현재 시판중인 $Profile^{(R)},\;ProTaper^{(R)},\;K3^{(R)},\;Hero\;642^{(R)},\;Hero\;Shaper^{(R)}$를 단면을 비교하고 이들 5가지 NiTi 파일과 사용방법에 따른 피로 파절 소요 시간을 비교하고자 시행되었다. 각 NiTi전동파일의 치근단 1/3을 temporary resin에 매몰시키고 다이아몬드 표면처리된 버로 잘라내어, 초음파를 이용하여 세척 후, 주사전자현미경으로 단면을 관찰하였다. 주기적인 피로 실험을 수행하기 위해, 회전속도, pecking 거리를 자동적으로 조절할 수 있는 장치를 제작하고 파일을 만곡된 상태를 재현하기 위하여 15도 경사진 금속 토막에 위치시키고 분당 300회전의 속도로 회전시켜 파일이 파절될 때까지의 시간을 측정하였다. 사용방법에 따른 실험군은 동적군과 정적군으로 나누고 pecking 거리는 3 mm, 6 mm로 하였다. 실험결과 동적군 보다는 정적군의 피로파절 소요시간이 통계학적으로 유의차 있게 짧았으며 3 mm, 6 mm의 pecking distance에 따른 영향은 나타나지 않았다. 결론적으로 NiTi전동파일은 pecking motion으로 사용하는 것이 피로파절을 줄이는데 도움이 될 것으로 사료된다.

• 구강회복응용과학지
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• 제33권2호
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• pp.80-87
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• 2017

목적: 이 연구는 새로운 레진계 근관실러인 Any-Seal의 여러 물성을 AH Plus Jet와 비교하여 평가하고자 했다. 연구 재료 및 방법: 흐름성, 방사선 불투과성, 압축 강도를 ISO 6876/2001기준에 의해 측정하였다. 흐름성은 실러 0.05 mL를 두 개의 유리판 사이에 놓고 100 g의 무게로 눌러 측정했다. 실러 혼합 10분 뒤 무게를 제거하고 눌려진 실러의 지름을 측정했다. 방사선 불투과성은 각 근관실러를 지름 10 mm, 높이 1 mm의 디스크형 시편으로 만들어 aluminum step wedge와 함께 방사선 촬영을 하여 분석했다. 압축 강도는 각 실러를 4 mm 지름과 6 mm 높이의 실린더 형태로 만든 다음 24시간 후와 1주일 후에 측정했다. 결과: 두 근관실러의 흐름성과 방사선 불투과성 값은 ISO 6876/2001조건에 맞았다. 흐름성은 AH Plus Jet와 Any-Seal 사이에 통계적으로 유의한 차이가 없었다(P > 0.05). AH Plus Jet가 방사선 불투과성 값을 나타냈다(P < 0.05). 24시간 후와 1주일 후 모두에서 AH Plus Jet가 더 높은 압축 강도를 보였다(P < 0.05). 결론: Any-Seal이 낮은 압축 강도를 보였으므로 다른 물리적, 생물적 특성에 대해 더 많은 연구가 임상적 활용 전에 필요할 것으로 생각한다.

• Restorative Dentistry and Endodontics
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• 제27권1호
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• pp.66-76
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• 2002

The purpose of this study is to evaluate the effectiveness of customized master cone on apical sealing in various apical size of prepared root canals, that is MAF(Master Apical File) and to know at which apical size the apical leakage is to be significantly reduced using customized master cone. 120 extracted single rooted premolars were divided into four groups according to their apical size(MAF), #30, 40, 50 and 60. And then, each group was subdivided into three in accordance with three obturation methods, lateral condensation with standardized master cone, lateral condensation with chloroform-dipped customized master cone, and continuous wave of obturation technique. Resorcinol-formaldehyde resin was used for the microleakage test of this study. Teeth were sectioned horizontally at 1.5mm(Level 1), 2.5mm(Level 2), and 3.5mm(Level 3) from the anatomical root apex using low speed microtome. All sections were examined under $\times$40 magnification with a stereomicroscope, photographed, and then scanned. With the scanned images, resin-infiltrated area presenting the microleakage was calculated using SigmaScan/Image, and the ratio of leakage to the total root canal area of each group was analyzed statistically(one way ANOVA). The results were as follows ; 1. In groups of MAF #30, there was no significant difference of mean leakage ratio among three obturation methods at all three levels. 2. In groups of MAF #40, the group using lateral condensation with customized master cone had the low-est mean leakage ratio at all three levels, but there was no significant difference among three obturation techniques. 3. In groups of MAF #50, the mean leakage ratio of the group using lateral condensation with standard master cone was the highest among those of three obturation techniques at level 1, and this difference was statistically significant(p<0.05). 4 In groups of MAF #60, the groups using lateral condensation with standard master cone had also the highest mean leakage ratio at all levels, but there was no significant difference at level 1 and 2. At level 3, the leakage of the group using lateral condensation with standard master cone was significantly higher than that of the group using continuous wave of obturation(p<0.05). The results of this study suggested that the obturation method using customized master cone or the continuous wave of obturation is more effective for apical sealing than that using standardized master cone when MAF is larger than ＃50.

• The Journal of Advanced Prosthodontics
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• 제8권3호
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• pp.194-200
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• 2016

PURPOSE. The prospective follow-up aimed to assess the performance of lithium disilicate crowns and clinical reasons of adverse events compromising survival and quality. MATERIALS AND METHODS. 58 patients were treated with 375 heat-pressed monolithic crowns, which were bonded with resin cement. Annual recalls up to five years included a complete dental examination as well as quality assessment using CDA-criteria. Any need for clinical intervention led to higher complication rate and any failure compromised the survival rate. Kaplan-Meier-method was applied to all crowns and a dataset containing one randomly selected crown from each patient. RESULTS. Due to drop-outs, 45 patients (31 females, 14 males) with the average age of 43 years (range = 17-73) who had 327 crowns (176 anterior, 151 posterior; 203 upper jaw, 124 lower jaw) were observed and evaluated for between 4 and 51 months (median = 28). Observation revealed 4 chippings, 3 losses of retention, 3 fractures, 3 secondary caries, 1 endodontic problem, and 1 tooth fracture. Four crowns had to be removed. Survival and complication rate was estimated 98.2% and 5.4% at 24 months, and 96.8% and 7.1% at 48 months. The complication rate was significantly higher for root canal treated teeth (12%, P<.01) at 24 months. At the last observation, over 90% of all crowns showed excellent ratings (CDA-rating Alfa) for color, marginal fit, and caries. CONCLUSION. Heat pressed lithium disilicate crowns showed an excellent performance. Besides a careful luting, dentists should be aware of patients' biological prerequisites (grade of caries, oral hygiene) to reach full success with these crowns.

• The Journal of Advanced Prosthodontics
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• 제5권4호
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• pp.457-463
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• 2013

PURPOSE. The purpose of this study was to compare the effect of a diode laser and traditional irrigants on the bond strength of self-adhesive cement. MATERIALS AND METHODS. Fifty-five incisors extracted due to periodontal problems were used. All teeth were instrumented using a set of rotary root canal instruments. The post spaces were enlarged for a No.14 (diameter, 1.4 mm) Snowlight (Abrasive technology, OH, USA) glass fiber reinforced composite post with matching drill. The teeth were randomly divided into 5 experimental groups of 11 teeth each. The post spaces were treated with the followings: Group 1: 5 mL 0.9% physiological saline; Group 2: 5 mL 5.25% sodium hypochlorite; Group 3: 5 mL 17% ethylene diamine tetra acetic acid (EDTA), Group 4: 37% orthophosphoric acid and Group 5: Photodynamic diode laser irradiation for 1 minute after application of light-active dye solution. Snowlight posts were luted with self-adhesive resin cement. Each root was sectioned perpendicular to its long axis to create 1 mm thick specimens. The push-out bond strength test method was used to measure bond strength. One tooth from each group was processed for scanning electron microscopic analysis. RESULTS. Bond strength values were as follow: Group 1 = 4.15 MPa; Group 2 = 3.00 MPa; Group 3 = 4.45 MPa; Group 4 = 6.96 MPa; and Group 5 = 8.93 MPa. These values were analysed using one-way ANOVA and Tukey honestly significant difference test (P<.05). Significantly higher bond strength values were obtained with the diode laser and orthophosphoric acid (P<.05). There were no differences found between the other groups (P> .05). CONCLUSION. Orthophosphoric acid and EDTA were more effective methods for removing the smear layer than the diode laser. However, the diode laser and orthophosphoric acid were more effective at the cement dentin interface than the EDTA, Therefore, modifying the smear layer may be more effective when a self-adhesive system is used.

• 대한소아치과학회지
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• 제32권1호
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• pp.158-163
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• 2005

외상으로 인해 완전 탈구와 함입성 및 정출성 탈구가 병합되어 나타나는 경우는 드물다. 2003년 7월에 10세 2개월의 여아가 상악우측 측절치의 완전탈구와 상악우측 중절치의 함입성 탈구, 상악 좌측 중절치의 정출성 탈구로 전남대학교병원 소아치과에 내원하였다. 내원 당일 외상치아를 외과적으로 재위치시켰으며 레진 강선 고정을 시행하였다. 외상 2주 후 완전탈구된 상악우측 측절치는 근관치료를 시행하였다. 외상 3개월 후 방사선사진 상에 상악 좌우측 중절치의 치근 외흡수가 관찰되었으며 수산화칼슘을 이용한 근관치료를 시행한 후 치근 외흡수가 정지되었다. 1년 4개월 동안의 관찰기간 동안 병적인 변화 없이 양호한 결과를 보였으며 추후 장기적인 추적관찰이 필요하리라 사료된다.