합착용 복합레진시멘트로 합착한 Machinable Ceramic과 상아질 사이의 인장강도에 대한 실험적 연구

조병훈 大韓齒科保存學會 1998 Restorative Dentistry & Endodontics Vol.23 No.1

The purpose of this study is to observe the corrosion characteristcs of four dental amalgams(CAULK FINE CUT, CAULK SPHERICAL, DISPERSALLOY, TYTIN) and to determine a function of chloride concentration through the anodic polarization curve obtained by using a potentistat. After each amalgam alloy and Hg being triturated, the triturated mass was inserted into the cylinderical metal mold, and condensed by hydrolic pressure. Each specimen was removed from the metal mold. 24 hours after condensation, specimens were polished with the emery paper and stored at room temperatrue for 6 months. The anocid polarization curves were employed to compare the corrosion behaviours of the amalgam in KCI and KCI-NaCI solution, which had chloride concentration of 0.4 g/l, 0.8 g/l, 1.2 g/l, and 1.6 g/l at 37℃ with 3-electrode potentiostat. After the immersion of specimen in electrolyte for 1 hour, the potential scan was begun. The potential scan range was 1500mV~+800mV(vs. S.C.E.) in the working electrode and the scan rate was 50mV/sec. The results were as follows. 1. The corrosion potential, the potential of anodic current peak, and transpassive potential in the solution of high chloride concentration shifted to more cathodic direction than those in thd solution of low concentration, and the current density in the solution of high chloride concentration was hifher than that in the solution of low concentration. 2. The corrosion potential, the potential of anodic current peak, and transpassive potential for CAULK FINE CUT amalgam were the most cathodic among the others, and the current density were the highest among the others. 3. In the solution of low chloride concentration, the corrosion potential, the potential of anodic current peak, and transpassive potential for DISPERSALLOY were the most anodic among the others, however in the solution of high chloride concentration, those for TYTIN were the most anodic among the others. 4. The anodic polarization curve for CAULK SPHERICAL was similar to that for high copper amalgams.

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.

기-액병류상향 충전탑에서 액체체류량과 축방향혼합특성

조지훈,손민일,박용성,함병호,김태옥 明知大學校 産業技術硏究所 1993 産業技術硏究所論文集 Vol.12 No.-

For upward cocurrent gas-liquid flow in a packed column, holdup and axial mixing characteristics of liquid were investigated. In an air-water-glass bead system. liquid holdup and residence time distribution(RTD) were measured and Peclet number based on axial dispersion model was evaluated from experimental RTD. We found that liquid holdup was increased with increasing liquid velocity and size of packing material, and it was decreased with increasing gas velocity. Also, liquid holdup for the cocurrent up flow system was larger than that for the downflow system at the same experimental conditions. As increasing gas velocity, the in fluence of packing size and operation method on liquid holdup was reduced. The calculated Peclet number was not affected by gas velocity, and it was increased with increasing liquid velocity and with decreasing packing size. Furthermore, the effect of liquid velocity on Petlet number for higher liquid Reynolds number(Re1>70) was larger than that for lower Re1. In these conditions, correlations of the dynamic liquid holdup and the Bodenstein number were obtained.

점적상에서의 수력학 특성

조지훈,성기천,함병호,김태옥 明知大學校 産業技術硏究所 1991 産業技術硏究所論文集 Vol.10 No.-

Hydrodynamics was investigated in a trickle bed with spherical particles. Flow transition boundary, pressure drop, and liquid holdup were measured and analyzed in an air-water system. The results showed that liquid velocity at trickle-pulse transition boundary increased with increasing packing size and it decreased with increasing gas velocity, and that the theoretical model proposed was well applicable to predicted flow transition boundary. In the same operation conditions, flow characteristics was changed with operation mode because of liquid closslinking. Therefore, as the maximum gas velocity increased, pressure drop increased. Also, pressure drop increased with increasing fluid velocity and it increased with decreasing packing size, and the effect of gas velocity on pressure drop for higher liquid velocity was less than that for lower liquid velocity. Liquid holdup increased with increasing liquid velocity and it decreased with increasing packing size, and the influence of gas velocity on liquid holdup for pulse flow regime had larger than that for trickie flow regime. By contrast, the influence of packing size on liquid holdup for pulse flow regime had less that for trickle flow regime. In this conditions, correlations of pressure drop and liquid holdup were proposed in terms of Reynolds numbers of total fluids and liquid phase.

CAD/CAM 으로 제작된 Ceramic Inlay의 변연누출에 관한 비교연구

조병훈,이명종,임미경,이광원,손호현 大韓齒科保存學會 1997 Restorative Dentistry & Endodontics Vol.22 No.2

To compare the marginal leakage of CAD/CAM-fabricated ceramic inlay, gold inlay and amalgam, forty extracted caries-free premolars were prepared with Class Ⅱ MO cavity design. The teeth were divided into four groups of ten samples each. Group 1 was restored with CAD/CAM-fabricated ceramic inlays cemented with Scotchbond Resin Cement / Scotchbond Multi-purpose plus. Group 2 was restored with gold inlays cemented with Scotchbond Resin Cement / Scotchbond Multi-purpose plus. Group 3 was restored with gold inlays cemented with zinc phosphate cement. And, Group 4 was restored with amalgam. All samples were thermocycled, and stored in 1% methylene blue. Marginal leakage was examined at four margins, that is, occlusal distal, priximal gingival, occlsal facial and occlusal lingual margins from sectioned samples under steeomicroscope(x15). The results were as follows: 1. Group 1 and 2 showed no statistically significant difference among marginal leakage at all four examined margins(p>0.05). 2. Group 3 and 4 showed significant marginal leakage at proximal gingival margin compared with other margins(p<0.05). 3. Significantly increased marginal leakage at priximal gingival, occlusal facial and occlusal lingual margins in group 3 were observed compared with other groups(p<0.05).

구강편평세포암종의 유세포분석적 DNA측정을 위한 이중 매개변수법의 적용

백병주,조남표,김재곤,주훈,김수야 大韓小兒齒科學會 1996 大韓小兒齒科學會誌 Vol.23 No.2

A series of 31 patients with primary oral squamous cell carcinoma (SCC) who were treated at Chonbuk National university Hospital during the years 1991-1995,were evaluated by dual parameter analysis in flow cytometric DNA measurement,Bryne's malignancy grading system,and the TNM classification.The aims of the present study were to discover that previously undetected aneuploid clones could be detected by dual parameter analysis and to determine the prognostic value of the above parameters. 1.Using dual parameter analysis of cytokenratin and DNA on disintegrated paraffin-embedded samples,aneuploid clones which were undetected by regular single parameter DNA analysis could be found among the cytokenratin-selected cells. DNA aneuploidy from parafin-embedded samples were 15 cases compared with 10 cases using conventional DNA analysis. 2.The portion of aneuploid tumors showed slightly higher clinical stage tumor size than the portion of diploid tumors, but the difference was not significant.The portion of DNA aneuploid tumors showed significantly higher mean mitosis and total malignancy scores than the portion of DNA diploid tumors. 3.The majority of the patients presented with clinical stage Ⅲ and Ⅳ lesions showed showed significantly higher mean total malignancy scores as compared to those with clinical stage Ⅰ and Ⅱ. 4.Histopatholgic mean total malignancy score of the 31 cases was 12.7.Among the histologic parameters,mean mitosis score was correlated to the status of DNA ploidy and total malignancy score were correlated to the DNA ploidy and clinical staging.

Histological evaluation of direct pulp capping with DSP-derived synthetic peptide in beagle dog

김재훈,홍준배,임범순,조병훈 대한치과보존학회 2009 Restorative Dentistry & Endodontics Vol.34 No.2

본 연구에서는 DSP (dentln sialoprotein)에서 유래된 합성 펩타이드를 동물실험 모델에 적용하여 치수노출 부위에 서 상아질 재생을 확인하고, 기존 치수복조제와의 성능 비교를 통해 새로운 치수복조제로서의 가능성을 확인하고자 하였다. 6 마리 비글견의 72 개의 치아를 이용하여, 실험적으로 치수를 노출하고 직접 치수 복조술을 시행하였다. 사용한 치수복조제는 (1) Ca(OH)₂ (CH군) (2) DSP 유도 합성 펩타이드 (PEP군) (3) 합성 펩타이드와 Ca(OH)₂ 혼합제(PEP+CH군) (4) White MTA (WMTA군) 이다. 노출된 치수에 치수복조제를 적용한 후 와동은 강화형 글라스 아이오노머로 충전하였다. 시술 후 2 주, 1 개월 및 3개월에 각각 2 마리씩 비글견을 희생시키고 조직시편을 제작하였다. 시편은 H&E 염색 후 광학 현미경으로 치수 염증 반응과 경조직 형성 정도를 관찰하였다. PEP군에서는 17 개의 시편 중 3 개의 시편에서만 경조직 형성을 관찰할 수 있었으며, 대부분의 시편에서 적절한 치수 회복을 관찰할 수 없었다. PEP군은 CH군에 비해 심한 염증반응을 보이고, 경조직 형성은 불량하였다. CH군과 WMTA군은 기계적으로 노출된 치수에서의 염증반응과 경조직 형성에 있어서 유사한 결과를 보였다. The purpose of this study was to investigate the pulpal response to direct pulp capping with dentin sialoprotein (DSP) -derived synthetic peptide in teeth of dogs and to compare its efficacy to capping substances Ca(OH)₂ and white mineral trioxide aggregate (WMTA). A total of 72 teeth of 6 healthy male beagle dogs were used. The mechanically exposed pulps were capped with one of the following: (1) DSP-derived synthetic peptide (PEP group): (2) Ca(OH)₂ (CH group): (3) a mixture paste of peptide and Ca(OH)₂ (PEP+CH group): or (4) white MTA (WMTA group). The access cavity was restored with a reinforced glass ionomer cement. Two dogs were sacrificed at each pre-determined intervals (2 weeks, 1 month and 3 months). After the specimens were prepared for standard histological processing sections were stained with hematoxylin and eosin. Under a light microscope inflammatory response and hard tissue formation were evaluated in a blind manner by 2 observers. In the PEP group only 3 of 17 specimens showed hard tissue formation indication that the DSP-derived synthetic peptide did not induce proper healing of the pulp. Compared with the CH group the PEP group demonstrated an increased inflammatory response and poor hard tissue formation. The CH and WMTA groups showed similar results for di rect pulp capping inmechanically exposed teeth of dogs.

기-액병류상향 고정층반응기에서 액체의 흐름과 축방향분산

함병호,조지훈,편무실,김태옥,손민일 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.-

For upward cocurrent gas-liquid flow in a fixed bed reactor, the flow and axial dispersion of liquid were investigated in an air-water-Zeolite particle system. Based on experimental residence time distributions, parameters of mixing models were evaluated with two proposed liquid mixing models: axial dispersion model with stagnant zone(DSM) and plug flow model with stagnant zone(PFM). Accordingly, the applicability and parameters of each mixing model were analyzed for various operating conditions. We found that the flow and axial mixing characteristics of liquid could be analyzed well by DSM and parameters were well estimated by curve fitting using trial and error method. Also, the fraction of stagnant zone was decreased with increasing liquid velocity, while the dimensionless mass transfer coefficient between dynamic and stagnant zones was increased, and these parameters estimated by DSM were lower than those by PFM. In dynamic zone, calculated Peclet number were increased with increasing liquid velocity and axial mixing characteristics of liquid tended to access to plug flow for the high liquid Reynolds number(about Re1>50). For the porous catalyst particle system the flow and axial mixing characteristics of liquid had nearly same tendency that for the nonporous particle(glass bead) system, while dimensionless mass transfer coefficient was lower value than that for it. In these conditions, correlations of these parameters were obtained for various operating conditions.

와동 형태와 충전 방법에 따른 Class Ⅴ복합 레진 수복치의 유한요소법적 응력 분석

엄정문,조병훈,손윤희 大韓齒科保存學會 2000 Restorative Dentistry & Endodontics Vol.25 No.1

치아파절에 관한 3차원유한요소법적 연구

엄정문,조병훈 大韓齒科保存學會 1993 Restorative Dentistry & Endodontics Vol.18 No.2

Restorative procedures can lead to tooth fracture due to the relatively small amount of the remaining tooth structure. It is essential to prevent fractures by having a clear concept of the designs for cavity preparations. Among the several parameters in cavity designs, profound understanding of isthmus width factor would facilitate selection of the approprate cavity preparation for a specific clinical situation. In this study, MO amalgam cavity were prepared on maxillary first premolar and filled with amalgam. Three dimensional model with 1365 8-node brick elements was maed by serial photographic method. In this model, isthmus was varied in width at 1/4, 1/3, 1/2 and 2/3 of intercuspal width and material properties were given for three element groups, i.e., enamel, dentin and amalgam. A load of 500 N was applied vertically on amalgam and enamel. In case of enamel loading, 2 model (with and without amalgam) was compared to consider the possibility of play at the interface between tooth material and amalgam. These models were analyzed with three dimensional finite element method. The results were as follows: 1. The stress was concentrated on the facio-pulpal line angle and distal marginal ridge of the cavity. 2. With the increase of the isthmus width, the stress spread around the facio-pulpal line angle and the area of stress concentration moved toward the proximal box. 3. In case of narrow isthmus width, the initiation point of crack would be in the area of isthmus corner of the cavity, and with the increase of the isthmus width, it would move toward the proximal box and at the same time the possibility of crack increase at the distal marginal ridge 4. The direction of crack progressed outward and downwark from the facio-pulpal line angle, and with the increase of the isthmus width, it approximated vertical direction. At the marginal ridge, it occurred in vertical direction. 5. It would be favorable to make the isthmus width narrower than a thrid of the intercuspal width, and to cover the cusp if isthmus width were than half of the intercuspal width. 6. It is necessary to apply the possibility of play to the finite element analysis.