수종의 apical plug 재료의 근단 폐쇄성에 관한 실험적 연구

최기운,허은정 大韓齒科保存學會 1994 Restorative Dentistry & Endodontics Vol.19 No.1

만곡근관에서 Thermafil 의 근단폐쇄성에 관한 실험적 연구

최기운,하주희 大韓齒科保存學會 1995 Restorative Dentistry & Endodontics Vol.20 No.2

Porphyromonas endodontalis 에 대한 Polyphosphate의 항균기전에 관한 연구

최성백,박상진,최기운,최호영 대한치과보존학회 2000 Restorative Dentistry & Endodontics Vol.25 No.4

Poly-P has been used to prevent decomposition of foods and has been shown to have inhibitory effect on the growth of gram positive bacteria. The purpose of this study was to evaluate the effect of poly-P on the growth of Porphyromonas endodontalis, a gram negative obligate anaerobic rod, endodontopathic bacterium. P. endodontalis ATCC 35406 was in BHI broth containing hemin and vitamin K with or without poly- P. Inhibitory effect of each poly-P which was added at the beginning(lag phase) or during(exponential phase) the culture, MIC(minimum inhibitory concentration) was determined by measuring the optical density of the bacterial cell at 540nm. Viable cell counts were measured to determined whether poly-P has a bactericidal effect. Leakage of intracellular nucleotides from P. endodontalis was determined at 260nm and morphological change of P. endodontalis was observed under the TEM(transmission electron microscope) . Binding of 32P-labeled poly-P to P. endodontalis was examined, SDS-polyacrylamide gel electrophoresis and zymography were performed to observe the changes in protein and enzyme profiles of P. endodontalis, respectively. The results from this study were as follows : 1.The minimal inhibitory concentration(MIC) of poly-P to P. endodontalis appeared to be 0.04~0.05%. 2.Poly-P added to the P. endodontalis culture during the exponential phase of P. endodontalis was as much effective as poly-P added at the begining of the culture, suggesting that the antibacterial effect of poly-P is not much dependent on the initial inoculum size of P. endodontalis. 3.Poly-P are bactericidal to P. endodontalis, demonstrating the decrease of the viable cell counts. 4.Intracellular nucleotide release from the P. endodontalis, was not increased in the presence of poly-P and was not reversed by the addition of divalent cations like Ca2+ and Mg2+. 5.Under the TEM, it was observed that fine electro-dense materials were prominent in the poly-P grown P. endodontalis, appearing locally in the cell, and the materials were more abundant and more dispersed in the cell as the incubation time with poly-P increased. In addition, highly electron dense granules accumulated in many poly-P grown cells, most of which were atypical in their shape. 6.Binding of 32P-labeled poly-P to P. endodontalis appeared to be 32,8 and 45.5 and 53.4% at 30 minutes, 1 hours and 2 hours, respectively. 7.In the presence of poly-P, the synthesis of proteins with apparent molecular masses of 25, 27, 35, 45 was lost or drastically decreased whereas expression of a protein with an apparent molecular mass of 75 was elevated. 8.Proteolytic activity of P. endodontalis was decreased by poly-P. The overall results suggest that use of poly-P may affect the growth of P. endodontalis, and the anti- bacterial activity of poly-P seems largely bactericidal. Changes in shape, protein expression, and proteolytic activity of P. endodontalis by poly-P may be directly and indirectly attributed to the antibacterial effect of poly-P. Further studies will be needed to confirm the effect of poly-P.

엔진구동형 NiTi 파일의 근관성형능력 비교

김보혜,최경규,박상혁,최기운 大韓齒科保存學會 2010 Restorative Dentistry & Endodontics Vol.35 No.2

The purpose of this study was to compare the root canal shaping ability of 4 rotary NiTi instruments in simulated root canals. For the preparation of thirty two curved root canals, Mtwo instruments using “single length”technique, and Profile, ProTaper Universal, and K3 using crown-down technique (N = 8) were used. All canal samples were prepared by reaching an apical canal size of #30. Pre- and post-instrumentation digital images were recorded and an assessment of canal shape was determined using a computer image analysis program SigmaScan Pro (Systat Software Inc., San Jose, CA, USA). The changes of the dimension of inner walls of canals, (2) the changes of the dimension of outer walls of canals, and (3) the centering ratio were measured at 7 measuring points, and then data were statistically analyzed using one-way ANOVA and Duncan’s test. The results were as below; 1. The root canal shaping ability of Profile was significantly faster than that of other rotary NiTi instruments (p < 0.05). 2. The deformation and fracture of all instruments used for this study were not experienced. 3. In the degree of changes of the dimension of inner walls of canals, Profile demonstrated the lowest changes of the dimension of inner walls of canals except at the measuring points of the 1 and 2 mm (p < 0.05). However, the ProTaper Universal showed the highest changes of the dimension of inner walls of canals at all measuring points (p < 0.05). 4. In the degree of changes of the dimension of outer walls of canals, Mtwo demonstrated the lowest changse of the dimension of outer walls of canals except at the measuring point of the 1 mm (p < 0.05). However, Profile exhibited the highest changes of the dimension of outer walls of canals at the measuring points of 3 and 4 mm and ProTaper Universal and K3 showed the largest changes of the dimension of outer walls of canals at the measuring points of 1, 2, 6, and 7 mm (p < 0.05). 5. In degree of centering ratio, Profile demonstrated the least centering ratio comparing with the centering ratio shown by other NiTi instruments at the measuring points of 1, 4, 5, and 6 mm. Results suggest that in the coronal part of canal preparation, active cutting files such as ProTaper Universal may efficiently flare the canal orifice and form a better taper, and in the apical part of the canal, files which have a better centering ability such as Profile may maintain the original canal curvature and reduce the shaping time. 이 연구의 목적은 4가지 엔진구동형 NiTi 기구의 근관성형력을 비교하는 것이다. 32개의 투명레진모형을 사용하여 파일의 단면도가 S자 형태이고“single length”방법으로 근관성형을 시행하는 Mtwo와 crown-down 방법으로 근관성형을 하는 Profile, ProTaper Universal 및 K3로 근관성형을 하였다 (n = 8). 모든 근관은 한사람의 술자가 근단공 크기가 #30이 될때까지 성형하였다. 기구 사용 전과 후 근관 모양을 디지털 영상을 기록하였고, 컴퓨터 영상 분석 프로그램(Expression Scanner와 Adobe Photoshop CS)으로 평가하였다. 다음과 같은 결론을 얻었다. 근첨으로부터 1, 2, 3, 4, 5, 6, 7 mm 떨어진 부위의 내측과 외측으로 삭제된 레진 양을 측정하였고, 자료는 SPSS법으로 비교 분석하였다. 1. 근관형성 시간은 Mtwo가 84.50초로 가장 짧았으며, 총 작업시간은 K3가 269.37초로 가장 길었다(p < 0.05). 2. 기구의 변형과 파절은 모든 구동형 NiTi 파일에서 발생하지 않았다. 3. 근관 내측 폭경의 변화는 Profile이 1, 2 mm 부위를 제외한 다른 부위에서 가장 적었으며, ProTaper Universal은 모든 부위에서 가장 많았다(p < 0.05). 4. 근관 외측 폭경의 변화는 Mtwo이 1 mm 부위를 제외한 모든 부위에서 가장 적었으며, Profile은 3, 4 mm 부위에서 가장 많았다(p < 0.05). ProTaper Universal와 K3는 1, 2, 6, 7 mm 부위에서 가장 많았다(p < 0.05). 5. 근관중심변위율(centering ratio)은 Profile이 1, 4, 5, 6 mm 부위에서 가장 적었다(p < 0.05). 이상의 결과, 구동성 NiTi 파일을 이용한 만곡 근관의 근관형성은 치경부는 ProTaper와 같은 삭제력이 높은 파일을 사용하는 것이 근관 입구를 효과적으로 넓히고 더 나은 taper를 형성하며, 근단부는 Profile과 같은 근관 중심 변위가 적은 파일을 사용하는 것이 근관형성 시간을 단축하고 근단부의 근관 변형(transportation)을 줄일 수 있다고 판단된다.

Glass-ionomer Cement 이장재의 세포독성에 관한 연구

박상진,최호영,나영민,민병순,최기운 大韓齒科保存學會 1993 Restorative Dentistry & Endodontics Vol.18 No.2

근단부 크기에 따른 customized master cone의 치근단 밀폐효과에 관한 연구

홍혜영,최호영,최기운 大韓齒科保存學會 2002 Restorative Dentistry & Endodontics Vol.27 No.1

The purpose of this study is to evaluate the effectiveness of customized mater 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 microtime. All sections were examined under ×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 analyze 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, thre group using lateral condensation with customized master cone had the lowest mean leakage ratio at all three levels, but there was no significant difference among there 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.

Porphyromonas endodontalis의 침투에 따른 혈관 내피세포의 유전자 발현

공희정,최경규,박상혁,이진용,최기운 대한치과보존학회 2009 Restorative Dentistry & Endodontics Vol.34 No.6

During the last two decades, there has been an increasing interest in the impact of oral health on atherosclerosis and subsequent cardiovascular disease (CVD). To date, some periodontal pathogens including Porphyromonas gingivalis (P. gingivalis) have been reported to be relevant to CVD. Porphyromonas endodontalis (P. endodontalis), which shares approximately 87% sequence homology with P. gingivalis, is mostly found within infected root canals. However, recent studies reveal that this pathogen also resides in the dental plaque or periodontal pocket in patients with periodontitis. It has been shown that P. endodontalis invades human coronary artery endothelial cells (HCAEC) and coronary artery smooth muscle cells (CASMC). To evaluate whether P. endodontalis can participate in the progression of atherosclerosis and CVD, we examined the changes in transcriptional gene expression profiles of HCAEC responding to invaion by P. endodontalis in this study. The following results were obtained. 1. Porphyromonas endodontalis was invasive of HCAEC. 2. According to the microarray analysis, there were 625 genes upregulated more than two-folds, while there were 154 genes downregulated by half. 3. Upregulated genes were relevant to inflammatory cytokines, apoptosis, coagulation and immune response. Enhanced expression of MMP-1 was also noticeable. 4. The transcription profiles of the 10 selected genes examined by real-time PCR agreed well with those observed in the microarray analysis. Thus, these results show that P. endodontalis presents the potential to trigger and augment atherosclerosis leading to CVD. 본 연구에서는 Porphyromonas endodontalis와 죽상경화증 및 심혈관질환과의 관계를 알아보기 위해, P. endodontalis가 사람의 관상동맥 내피세포에 침투했을 때 나타나는 유전자 발현의 변화를 microarray와 real-time PCR로 측정하였고, 발현이 증가된 유전자 중에서 죽상경화증과 연관된 유전자들이 관련 KEGG pathway 상에서 유의성 있는 영향을 미치는지를 분석하여 다음과 같은 결과를 얻었다. 1. Porphyromonas endodontalis는 사람의 관상동맥 내피세포에 침투하였다. 2. Microarray 분석결과, 대조군보다 발현이 2배 이상 증가된 유전자는 625개였고, 1/2이하로 감소된 유전자는 154개였다. 3. 발현이 2배 이상 증가된 유전자 중에는 염증성 cytokine 및 chemokine, 세포자멸사, 혈액응고와 면역반응 관련 유전자들이 포함되었다. 4. Microarray 분석결과를 확인하기 위해 발현이 2배 이상 증가된 유전자 중에서 10개의 유전자를 선택하여 real-time PCR을 시행하였고, 그 결과 microarray에서와 마찬가지로 발현 정도가 대조군보다 모두 높게 나타났다. 따라서 P. endodontalis가 사람의 관상동맥 내피세포에 만성적으로 작용했을 때, 심혈관질환에서 중요한 부분을 차지하는 죽상경화증을 유발하는 위험 요소 중의 하나로 작용할 수 있을 것으로 판단된다. 이와 관련된 자세한 기전을 이해하기 위해서는 앞으로 더 많은 연구가 필요할 것으로 보인다.

레진 시멘트의 film thickness가 간접 복합 레진 수복물의 접착 효율에 미치는 영향에 관한 연구

이상혁,최기운,최경규 大韓齒科保存學會 2010 Restorative Dentistry & Endodontics Vol.35 No.2

본 연구는 여러 레진 시멘트의 film thickness에 따른 상아질과 간접 레진 수복물 간의 미세인장 결합 강도를 측정하고, 각 레진 시멘트의 중합 수축 및 굴곡 강도, 탄성 계수를 비교 분석하며, 접착 계면 및 파단면의 주사전자 현미경 관찰을 통하여 레진 시멘트의 film thickness가 레진 간접 수복물의 접착 효율에 미치는 영향을 평가하고자 시행하였다. 복합 레진형 레진 시멘트인 Variolink II와 Duo-Link, 접착형 레진 시멘트인 Panavia F와 Rely X Unicem의 4가지 레진 시멘트를 사용하였고, 각각의 시멘트를 film thickness에 따라 < 50 μm (control)의 대조군과 50 μm (T50), 100 μm (T100), 150 μm (T150)의 실험군으로 나누어 총 16개의 군으로 분류하였다. 데이터는 ANOVA와 Duncan’s multiple comparison test (p < 0.05)를 이용하여 통계 분석하였으며 다음과 같은 결론을 얻었다; 1. Variolink Ⅱ는 모든 film thickness에서 접착형 레진 시멘트보다 높은 결합 강도를 나타냈지만(p < 0.05), Duo-Link는 대조군을 제외하고는 통계학적 유의차가 없었다(p > 0.05). 2. Film thickness가 증가할수록 복합 레진형 레진 시멘트의 결합 강도는 유의성 있게 감소(p < 0.05)하는 경향을 보인 반면, 접착형 레진 시멘트는 통계학적 유의차가 없었다(p > 0.05). 3. Panavia F는 통계학적으로 유의성 있게 낮은 중합 수축량을 나타냈다(p < 0.05). 4. 굴곡 강도와 탄성 계수는 복합 레진형 레진 시멘트가 접착형 레진 시멘트보다 유의성 있게 높게 나타났다(p < 0.05). 5. FE-SEM 관찰 결과 결합 강도가 높은 복합 레진형 레진 시멘트는 균일한 접착층과 잘 발달된 resin tag 소견을 보였으나, 접착형 레진 시멘트는 불분명한 접착층과 resin tag 소견을 나타냈다. 파단면 관찰에서 복합 레진형 레진 시멘트는 혼합형 파괴 양상을 나타냈으나 접착형 레진 시멘트는 접착성 파괴 양상을 나타냈다. The purpose of this study was to evaluate the effect of film thickness of various resin cements on bonding efficiency in indirect composite restoration by measurement of microtensile bond strength, polymerization shrinkage, flexural strength and modulus, fractographic FE-SEM analysis. Experimental groups were divided according to film thickness (< 50 μm-control, 50 μm-T50, 100 μm-T100, 150 μm-T150) using composite- based resin cements (Variolink Ⅱ, Duo-Link) and adhesive-based resin cements (Panavia F, Rely X Unicem). The data was analyzed using ANOVA and Duncan’s multiple comparison test (p < 0.05). The results were as follows ; 1. Variolink Ⅱ showed higher microtensile bond strength than that of adhesive-based resin cements in all film thickness (p < 0.05) but Duo-Link did not show significant difference except control group (p > 0.05). 2. Microtensile bond strength of composite-based resin cements were decreased significantly according to increasing film thickness (p < 0.05) but adhesive-based resin cements did not show significant difference among film thickness (p > 0.05). 3. Panavia F showed significantly lower polymerization shrinkage than other resin cements (p < 0.05). 4. Composite-based resin cements showed significantly higher flexural strength and modulus than adhesive- based resin cements (p < 0.05). 5. FE-SEM examination showed uniform adhesive layer and well developed resin tags in composite-based resin cements but unclear adhesive layer and poorly developed resin tags in adhesive-based resin cements. In debonded surface examination, composite-based resin cements showed mixed failures but adhesive-based resin cements showed adhesive failures.

Spreader의 종류와 Accessory cone의 접합성에 따른 근단폐쇄성에 관한 실험적 연구

안영미,최기운 大韓齒科保存學會 1994 Restorative Dentistry & Endodontics Vol.19 No.2

산부식형 상아질 접착제의 접착 내구성에 관한 연구

정미라,최기운,박상혁,박상진 대한치과보존학회 2007 Restorative Dentistry & Endodontics Vol.32 No.4