산부식후 상아질 표면의 습윤 또는 건조가 상아질 결합에 미치는 영향

손호현,권혁춘,양원경 大韓齒科保存學會 2000 Restorative Dentistry & Endodontics Vol.25 No.2

Iridoid 화합물이 치수절단 후 잔존치수 조직에 미치는 영향

권혁춘,박동성,손호현 大韓齒科保存學會 1997 Restorative Dentistry & Endodontics Vol.22 No.2

Aucubin, an iridoid glucoside, which is isolated form Aucuba japonica, has some biological effects. This study was to investigate the effect of aucubin on the remainig pulp tissues after pulpotomy. Mongrel dog's coronal pulps were mechanically exposed with a sterile round bur and excised with sterile sharp excarvator. After bleeding was controlled, in control group, Ca(OH)_2 powder was applied on the remaining pulps and the cavities were sealed with Z.O.E cement. In experimental group 1, mixed powder with Ca(OH)_2 and aucubin(1:1 by weight) was applied on the pulotomized pulp surfaces. After th cavities were covered with sterile aluminum foil, they were sealed with Z.O.E. cement. In experimental group 2, only aucubin powder was applied on the remaining pulps and then they were treated the same as experimental group 1. In the all groups, the pulps were histopathologically observed by light microscope at the time intervals of 1, 2 and 4 weeks after experiment. The results were as follows: 1. In control and experimental groups, mild vascular congestion and bleeding were found in most of the specimens. Less inflammatory infiltration was observed in experimental groups than in control group. 2. Dentin bridge formation was found after 1 week at both control and experimental group 1. Dentin birdge had discontinuous osteodentin like appearance of contained some dentin chips. In experimental group 2, dentin bridge was not seen. 3. The coagulation necrosis layer on the remaining pulp tissues was seen in all groups. In experimental group 2, the thickest layer was observed. And in control group, coagulation necrosis layer was similar as in experimental group 1.

모티리움 엠정(말레인산돔페리돈 12.72 mg)에 대한 한미 돔페리돈정의 생물학적 동등성

곽손혁,우종수,황성주 충남대학교 약학대학 의약품개발연구소 2002 藥學論文集 Vol.17 No.-

Bioequivalence of two domperidone maleate tablets, test drug (Hanmi Domperidone^ⓡ tablet: Hanmi Pharmaceutical Co.) and reference drug (Motilium-M^ⓡ tablet: Jassen Korea Pharm. Co.), was evaluated according to the guidelines of Korea Food and Drug Administration (KFDA). Twenty four healthy male volunteers were divided randomly into two groups and administered the drug orally at the dose of 20㎎ as domperidone in a 2×2 crossover study. There was a week washout period between administrations. Blood samples were taken at predetermined time intervals for 48hr and the plasma concentration of domperidone was determined by a HPLC method. AUC_0-48hr (area under the plasma concentration-time curve from time zero to 48hr), C_max (maximum plasma drug concentration) and T_max, (time to reach C_max) were estimated from the plasma drug concentration-time data. Analysis of variance (ANOVA) revealed no difference in AUC_0-48hr, C_max and T_max between two products. The apparent differences of these parameters between two products were less than 20% (i.e., 1.047, -0.416 and 9.347% for AUC_0-10hr, C_max and T_max, respectively). The powers (1-β) for AUC_0-48hr, C_max and T_max were over 0.99. Minimal detectable differences (Δ) at α=0.05, 1-β=0.8 were less than 20% (i.e. 11.15, 10.21 and 18.13% for AUC_0-10hr, C_max and T_max respectively). The 95% Confidence intervals (δ) for these parameters were also within ±20% (i.e. -5.49≤δ≤7.58, -6.39≤δ≤5.57 and -1.28≤δ≤19.95 for AUC_0-10hr, C_max and T_max, respectively). These results satisfied the criteria of KFDA guidelines for bioequivalence, indicating the two tablets of domperidone maleate were bioequivalent.

티로파 정(염산티로프라미드 100 mg) 에 대한 안티모딕정의 생물학적 동등성

곽손혁,구선회,린팜두안,강종성,황성주 충남대학교 약학대학 의약품개발연구소 2000 藥學論文集 Vol.16 No.-

Bioequivalence of two tiropramide tablets, test drug (Antimodic® tablet: Chong Kun Dang Pharm. Co.) and reference drug (Tiropa® tablet: Dae Woong Pharm. Co.), was evaluated according to the guidelines of Korea Food and Drug Administration (KFDA). Twenty healthy male volunteers were divided randomly into two groups and administered the drug orally at the dose of 100 mg as tiropramide hydrochloride in a 2×2 crossover study. There was a week washout period between administrations. Blood samples were taken at predetermined time intervals for 10 hr and the plasma concentration of tiropramide HCl was determined by a GC/MS method. AUC_0-10hr (area under the plasma concentration-time curve from time zero to 10 hr), C_max (maximum plasma drug concentration) and T_max (time to reach C_max) were estimated from the plasma drug concentration-time data. Analysis of variance (ANOVA) revealed no difference in AUC_(0-10hr), C_max and T_max between two products. The apparent differences of these parameters between two products were less than 20% (i.e., 0.043, 6.430 and 8.929% for AUC_(0-10hr), C_max and T_max, respectively). The powers (1-β) for AUC_(0-10hr) and C_max were over 0.9. Minimal detectable differences (Δ) at α=0.05, 1-β=0.8 were less than 20% (i.e. 15.71 and 12.53% for AUC_(0-10hr) and C_max, respectively). The 90% confidence intervals (δ) for these parameters were also within ±20% (i.e. -9.15≤δ≤9.24 and -0.90≤δ≤13.77 for AUC_(0-10hr) and C_max, respectively). These results satisfied the criteria of KFDA guidelines for bioequivalence, indicating the two tablets of tiropramide were bioequivalent.

프레팔시드정(시사프리드 5 mg)에 대한 시사컨시드정의 생물학적 동등성

곽손혁,구선회,황성주 충남대학교 약학대학 의약품개발연구소 2000 藥學論文集 Vol.16 No.-

Bioequivalence of two cisapride tablets, test drug (Cisaconsid® tablet: Hankook Nelson Pharm Co.) and reference drug (Prepulsid® tablet. Yansen Pharm. Co.), was evaluated according to the guidelines of Korea Food and Drug Administration (KFDA). Eighteen healthy male volunteers were divided randomly into two groups and administered the drug orally at the dose of 10 mg as cisapride in a 2×2 crossover study. There was a week washout period between administrations. Blood samples were taken at predetermined time intervals for 36 hr and the plasma concentration of cisapride was determined by a HPLC method. AUC_(0-36hr) (area under the plasma concentration-time curve from time zero to 36 hr), C_max (maximum plasma drug concentration) and T_max (time to reach C_max) were estimated from the plasma drug concentration-time data. Analysis of variance (ANOVA) revealed no difference in AUC_(0-36hr), C_max and T_max between two products. The apparent differences of these parameters between two products were less than 20% (i.e., 2.23, 7.99 and 3.81% for AUC_(0-36hr), C_max and T_max., respectively). The powers (1-β) for AUC_(0-36hr), C_max and T_max were over 0.9. Minimal detectable differences (Δ) at α=0.10, 1-β=0.8 were less than 20% (i.e. 16.34, 13.81 and 17.99% for AUC_(0-36hr), C_max and T_max, respectively). The 90% confidence intervals (δ) for these parameters were also within ±20% (i.e. -13.21≤δ≤8.75, -17.27≤δ≤1.28 and -l5.93≤δ≤8.24% for AUC_(0-36hr), C_max and T_max, respectively). These results satisfied the criteria of KFDA guidelines for bioequivalence, indicating the two tablets of cisapride were bioequivalent.

ATM망 트래픽 제어 알고리즘 연구

유진호,손준영,안재환,박성우,김명수,장혁수 明知大學校 産業技術硏究所 1996 産業技術硏究所論文集 Vol.15 No.-

ATM(Asynchronous Transfer Mode) is a transmission technique for the B-lSDN(Broadband Integrated Service Digital Network). Congestion problems are unavoidable in the ATM networks, since various traffic typos coexist in the networks. The preventive congestion control algorithm is widely used for the real time traffics such as voice and video. The reactive congestion control algorithm works well for the non-real time traffic within a short distance. A mixed traffic control algorithm is proposed, which works either preventively or reactively based on traffic types. The proposed algorithm sets a high and low threshold value at the output buffers and modifies the EPRCA(Enhanced Proportion Rate Control Algorithm) to control loss-sensitive cells. Delay-sensitive cells are handled by the priority control and the UPC(Usage Parameter Control) algorithm. The performance analysis shows that the proposed traffic control algorithm works well for both the VBR(Variab1e Bit Rate) and ABR(Available Bit Rate) traffic with small buffers

점도, 시편형태 그리고 접착의 유무가 광중합 복합레진의 선형중합수축의 측정에 미치는 영향

이인복,손호현,권혁춘,엄정문,조병훈 大韓齒科保存學會 2003 Restorative Dentistry & Endodontics Vol.28 No.6

Objectives. The aim of study was to investigate the effect of flow, specimen geometry and adhesion on the measurement of linear polymerization shrinkage of light cured composite resins using linear shrinkage measuring device. Methods. Four commercially available composites an anterior posterior hybrid composite Z100, a posterior packable composite P60 and two flowable composites, Filtek flow and Tetric flow were studied. The linear polymerization shrinkage of composites was determined using 'bonded disc method' and 'non bond ed' free shrinkage method at varying C factor in the range of 1~8 by changing specimen geometry. These measured linear shrinkage values were compared with free volumetric shrinkage values. The viscosity and flow of composites were determined and compared by measuring the dropping speed of metal rod under constant load. Results. In non bonded method, the linear shrinkage approximated one third of true volumetric shrink age by isotropic contraction. However, in bonded disc method, as the bonded surface increased the linear shrinkage increased up to volumetric shrinkage value by anisotropic contraction. The linear shrinkage value increased with increasing C factor and approximated true volumetric shrinkage and reached plateau at about C factor 5~6. The more flow the composite was, reduced linear shrinkage was measured by compensation radial flow.

상아질 접착제의 중합 시간 조절에 따른 복합레진의 중합 수축 방향의 변화

배지현,오명환,김창근,손호현,엄정문,조병훈,권혁춘 대한치과보존학회 2001 Restorative Dentistry & Endodontics Vol.26 No.4

The purpose of this study was to evaluate the effect of adhesive curing timing on the direction of polymerization shrinkage of light-curing composite resin. In this study, the curing times of adhesive and composite resin were measured by differential scanning calorimeter(DSC). 28 extracted human molars were embedded in clear resin and box-type cavities were prepared. Based on DSC data. the experimental teeth were divided into 4 groups. Group 1: no bond: Group 2: late curing: Group 3: Intermediate curing: Group 4: Early curing. After treating with adhesive, the buccal cavities were filled with Z-100 hybrid composite resin and the lingual ones were filled with AEliteflo flowable composite resin. The depressions at the surface were measured by surface profilometer, then the specimens were embedded in clear resin and sectioned. Impressions were obtained and used to get epoxy resin replicas. The epoxy replicas were gold-coated and observed under SEM. Average Maximum Gap(AMG), Gap Proportion(GP), Average Marginal Index(AMI) were used to compare the shrinkage gap of each group. The results were statistically analyzed using the Kruskal-Wallis One Way ANOVA, Student-Newman-Keuls method. The results of this study were as follows. 1. Average Maximum Gap. Gap Proportion, Average Marginal Index and depression at the surface of Z-100 hybride composite resin were smailer than those of AEliteflo flowable composite resin(P(0.05) 2. When the bonding between composite resin and tooth structure was strong, the shrinkage gap was small, and depression at the surface was deep(P<0.05). 3. In the well-bonded group. light-curing composite resin shrank toward bonded cavity wall. not toward light source. The result suggested that the direction of polumerization shrinkage was affected by the quality of bonding in the dentin-resin interface. The strong was the bonding between composite resin and tooth structure, the smaller was the gap and the deeper was the depression at the surface. Then the flow to compensate the polymerization shrinkage proceeded from surface to bonded cavity wall.

유동성 및 응축성 복합레진의 점탄성에 관한 유변학적 연구

조병훈,이인복,권혁춘,손호현,엄정문 대한치과보존학회 2000 Restorative Dentistry & Endodontics Vol.25 No.3

The purpose of this investigation was to observe the viscoelastic properties of five commercial flowable(Aeliteflo, Flow it, Revolution, Tetric flow, Compoglass flow) , three conventional hybrid(Z-100,Z-250,P-60) and two condensable(Synergy compact, SureFil) resin composites. A dynamic oscillatory shear test was done to evaluate the storage shear' modulus (G' ) , loss shear modulus(G") , loss tangent(tan δ) and complex viscosity(η* ) of the resin composites as a function of frequency dynamic frequency sweep test from 0.01 to 100 rad/s at 25℃ - by using Advanced Rheometric Exparusion SystemtARES) . To investigate the effect On the viscosity of resin composites of filler volume fraction, the filler weight % and volume % were measured by means of Archimedes' principle using a pyknometer. The results were as follows 1.The complex viscosity η* of flowable resins was lower than that of hybrid resins and significant differences were observed between brands. The complex viscosity η* of condensable resins was higher than that of hybrid resins. The order of complex viscosity η* at ω = 10 rad/s was as follows. Surefil, Synergy compact, P-60, Z-250, Z-100. Aeliteflo, Tetric flow, Compoglass flow, Flow it, Revolution. The relative complex viscosity of flowable resins compared to Z-100 was 0.04-0.56 but Surefil was 30.4 times higher than that of Z-100. 2.The storage shear modulus G' and the loss shear modulus G" of flowable resins were lower than those of hybrid resins but those of condensable resins were higher. The patterns of the change of loss tangent, tan δ of resin composites with increasing frequency were significantly different between brands.The phase angles,δ, ranged from 30.2-78.1˚at ω = 10 rad/s. 3.A11 composite resins represent pseudoplastic nature with increasing shear rate. 4.The complex shear modulus G* and the phase angle δ was represented by the frequency domain phaser form, G*( ω )= G* eIδ = G*〈 δ. The locus Of frequency domain phaser plots in a complex plane was a valuable method that represent the viscoelastic properties of composite resins. 5.There was no direct linear correlationship but a weak positive relation was observed between filler volume % or weight % and the viscosity of the resin composites.

Flowable 및 microfill 복합레진으로 충전된 제 5급와동에서 load cycling 전,후의 미세변연누출 비교

강석호,김오영,오명환,조병훈,엄정문,권혁춘,손호현 大韓齒科保存學會 2002 Restorative Dentistry & Endodontics Vol.27 No.2

Low-viscosity composite resins may produce better sealed margins than stiffer compositions (KempScholte and Davidson, 1988; Crim, 1989). Flowable composites have been recommended for use in Class V cavities but it is also controversial because of its high rates of shrinkage. On the other hand, in the study comparing elastic moduli and leakage, the microfil had the least leakage (Rundle et al. 1997). Furthermore, in the 1996 survey of the Reality Editorial Team, microfills were the clear choice for abfraction lesions. The purpose of this study was to evaluate the microleakage of 6 composite resins (2 hybrids, 2 microfills, and 2 flowable composites) with and without load cycling. Notch-shaped Class V cavities were prepared on buccal surface of 180 extracted human upper premolars on cementum margin. The teeth were randomly divided into non-load cycling group (group 1) and load cycling group(group 2) of 90 teeth each. The experimental teeth of each group were randomly divided into 6 subgroups of 15 samples. All preparations were etched, and Single bond was applied. Preparations were restored with the following materials (n=15) : hybrid composite resin [Z250(3M Dental Products Inc. St.Paul, USA), Denfil(Vericom, Ahnyang, Korea)], microfil [Heliomolar RO(Vivadent, Schaan, Liechtenstein), Micronew(Bisco Inc. Schaumburg, IL, USA)], and flowable composite[AeliteFlo(Bisco Inc. Schaumburg, IL, USA), Revolution(Kerr Corp. Orange, CA, USA)]. Teeth of group 2 were subjected to occlusal load (100N for 50,000 cycles) using chewing simulator(MTS 858 Mini Bionix Ⅱ system, MTS Systems Corp., Minn, USA). All samples were coated with nail polish 1mm short of the restoration, placed in 2% methylene blue for 24 hours, and sectioned with a diamond wheel. Enamel and dentin/cementum margins were analyzed for microleakage on a sclale of 0 (no leakage) to 3 (3/3 of wall). Results were statistically analyzed by Kruskal-Wallis One way analysis, Mann-Whitney U-test, and Student-Newmann-Keuls method. (p=0.05) Results: 1. There was significantly less microleage in enamel margins than dentinal margins of all groups. (p<0.05) 2. There was no significant difference between six composite resin in enamel margin of group 1. 3. In dentin margin of group 1, flowable composite had more microleakage than others but not of significant differences. 4. There was no significant difference between six composite resin in enamel margin of group 2. 5. In dentin margin of group 2, the microleakage were R>A=H=M>D>Z. But there was no significant differences. 6. In enamel margins, load cycling did not affect the marginal microleakage in significant degree. 7. In dentin margins, load cycling did affect the marginal microleakage only in Revolution. (p<0.05)