치과용 라미네이트 도재의 피로파괴에 관한 실험적 연구

박찬운,배태성,이상돈,Park Charn-Woon,Bae Tae-Sung,Lee Sang-Don 대한치과보철학회 1993 대한치과보철학회지 Vol.31 No.4

The purpose of this study was to evaluate the fracture characteristics and the effect of resin bonding of laminate porcelain. In order to characterize the indentation-induced crack, Young's moduli and characteristic indentation dimensions were measured. The fatigue life under three point flexure test was measured using the electro-dynamic type fatigue machine, and the crack propagation with thermocycling was investigated on the condition of 15 second dwell time each in $5^{\circ}C\;and\;55^{\circ}C$ bath. The Vickers indentation pattern and the fracture surface were examined by an optical microscope and a scanning electron microscope (SEM). The results obtained were summarized as follows ; 1. Young's moduli(E) of the laminate porcelain and the resin cement used in this experiment were $62.56{\pm}3.79GPa$ and $15.01{\pm}0.12GPa$, respectively. 2. The initial crack size of the laminate porcelain was $69.19{\pm}5.94{\mu}m$ when an indentation load of 9.8N was applied, and the fracture toughness was $1.065{\pm}0.156MPa\;m^{1/2}$. 3. The fatigue life of laminate porcelain showed the constant fracture range at the stress level 27.46-35.30MPa. 4. When a cyclic flexure load was applied, the fatigue life of resin-bonded laminate porcelain was more decreased than that of laminate porcelain. 5. When a thermocycling was conducted, the crack growth rate of resin-bonded laminate porcelain was more increased than that of laminate porcelain. 6. Fracture surface showed the radial crack, the lateral crack, and the macroscopic crack branching region beneath the plastic deformation region when an indentation load of 9.8N was applied.

Pantographic Reproducibility Index(PRI)를 이용한 하악운동의 재현성에 관한 연구

이상돈,박찬운,Lee, Sang-Don,Park, Charn-Woon 대한치과보철학회 1986 대한치과보철학회지 Vol.24 No.1

In order to determine if a relationship exists between the clinical symptoms of TMJ dysfunction and the reproducibility of mandibular movements, twenty one subjects were chosen. The control group consisted of 5 subjects who were determined to be free from signs and symptoms of dysfunction . The sixteen experimental subjects were selected on the basis of their having dysfunctional symptoms. The author obtained two sets of pantographic tracings. Each set consisted of tracings from three both lateral and one protrusive movements. A second set of tracings were recorded immediately on the new recording papers using the same procedure as the first tracing. The tracings were scored by Pantographic reproducibility index (PRI). The obtained results were as follows. 1. Mean PRI scores of groups increased as the degree of dysfunction were increased. 2. For the groups of no or slight dysfunctional symptoms the PRI scores of the second tracing were smaller than the first one, wherea the scores of the second tracing from $D_2,\;D_3$ group were larger than the first tracing. 3. Differences between the mean PRI scores of control group and those of experimental group were statistically significant. 4. The second sets of tracings were more reliable statistically than those of first ones. 5. PRI can be used as a meaningful aid for the evaluation of the diagnostic and therapeutic results of treatment modalities for the TMJ dysfunction. 6. At 3east two sets of tracings should be recorded when the PRI is to be used to detect the incoordinated movements of TMJ dysfunction patient. 7. PRI scores of control group ($D_0$) was 137.7, thus, mandibular movement was reproducible, whereas PRI scores of experimental groups ($D_1,\;D_2,\;D_3$) were 22.5, 27.7, 30.45 respectively, thus were nonreproducible.

가시광선영역에서 shade guide에 따른 광투과도 특성 연구

최근배,박찬운,송창용,고석민,Choi, Keun-Bae,Park, Charn-Woon,Song, Chang-Yong,Ko, Sok-Min 대한치과보철학회 2000 대한치과보철학회지 Vol.38 No.2

The purpose of this study was the evaluation of spectral transmission of the commercial three shade guides and the relationship of hue, value, and chroma according to the transmission rate. The spectral transmittance of three shade guides - Vita Lumin Shade Guide, Vintage and Unibond Shade Guide, and Vitapan 3D-Master Shade Guide - were measured. For direct transmission measurements, each shade tabs were placed at the entrance port of the 1mm diameter intergrating sphere. The intensity of the light source passing through the shade tabs to the right angle was continuously recorded for wavelength from 400 to 700 nm. A transmission spectrum and digital data were obtained for each measurement and they were evaluated using Microcal Origin program. The obtained results of this study were as follows : 1. In Vita Lumin Shade Guide, sum of the transmission rate of the shade tabs at the wavelength 400-700nm was decreased in agreement with the arrangement order at each A, B, C, D group, except D4 shade tab. However, there were no relationships between the transmission rate of the shade tabs and the value-oriented. 2. In Vintage and Unibond Shade Guide, sum of the total transmission rate of the shade tabs was decreased in agreement with the arrangement order at each A, B, C, B group. When all shade tabs arranged in value-oriented, transmission rate was accord with the order, except D4 shade tab. 3. When shade tabs of the Vitapan 3D-Master Shade Guide have the same value and hue, sum of their total transmission rate decreased in accordance with the chroma-oriented. When the shade tabs have the same value and chroma, there were no differences from the order of the transmission rate to the various hue type. However, in the 'R' tabs of reddish hue type, the transmission rate increased at the long wavelength range area. In conclusion, we need the quantitative analyzing instruments in transmission determination. Vitapan 3D-Master Shade Guide covers the tooth color space taking into account the parameters of the systematic value, chroma, hue oriented, and the transmission rate relatively accorded with that sequence.

혼수비에 따른 초경석고의 파절강도

엄정희,박찬운,박광선,Eoum Jung-Hee,Park Charn-Woon,Park Kwang-Sun 대한치과보철학회 2001 대한치과보철학회지 Vol.39 No.2

This study was performed to evaluate the fracture resistance of three improved die stone materials according to water/powder ratio. There are lots of handling conditions which affect the physical properties of improved dental stone, and it's well known that the water/powder ratio significantly affect the strength of die stone. If water/power ratio was incorrect, following disadvantages were showed : (1) susceptibility to dimensional change due to abrasion, (2) limited reproduction of fine detail, (3) lack of strength. The maxillary master casts were made of additional silicone impressions(Exaflex, GC America. Inc. USA). Three type IV die stones such as Fuji Rock (GC Europe Intreleuvenlaan, Leuven, Belgium), Velmix(Kerr, Manufacturing company, USA), and Crytal Rock( Maruishi Gypsum Co. Ltd, Japan) were tested. A total of 160 casts were prepared, separated, and tested on the Instron Testing Machine(Model 4201, Co. USA). The obtained results of this study were as follows : 1. Fuji Reck and Velmix less 3ml than the water/power ratio of manufacturer's instruction showed the highest resistance to fracture. According to increasing water/powder ratio, fracture resistance was significantly increased(P<0.05). Crystal Rock showed the highest fracture value when it was mixed with the water/power ratio of manufacturer's instruction. 2. Water/powder ratio of the manufacturer's instructions and less 3ml than that showed lower fracture value of hand mix than that of vacuum mix. Water/powder ratio of more 3ml, 6ml than manufacturer's instructions was not significantly different between hand mix and vacuum mix(p>0.05). 3. Velmix had the highest viscoelastic value among three die materials when it was mixed with the manufacturer's instruction. Viscoelasticity was decreased according to increasing water/powder ratio.

불산 식각 농도 및 시간이 lithium disilicate 도재와 레진시멘트의 전단결합강도에 미치는 영향

서재민,박찬운,안승근,Seo, Jae-Min,Park, Charn-Woon,Ahn, Seung-Geun 대한치과보철학회 2007 대한치과보철학회지 Vol.45 No.4

Purpose: The objective of this study was to evaluate the effects of hydrofluoric acid concentration & etching time on the shear bond strength between IPS Empress 2 ceramic and resin cement. Material and methods: Thirty three rectangular shape ceramic specimens($20{\times}12{\times}5mm$ size, IPS Empress 2 core materials) were used for this study. The ceramic specimens divided into ten experimental groups with three specimens in each group and were etched with hydrofluoric acid(4%, 9%) according to different etching times(30s, 60s, 90s, 120s, 180s). Etched surfaces of ceramic specimens were bonded with resin cement(Rely X Unicorn) using acrylic glass tube. All cemented specimens were tested under shear loading until fracture on universal testing machine at a crosshead speed of 0.5mm/min and the maximum load at fracture(kg) was recorded. Collected shear bond strength data were analyzed with one way ANOVA and Duncan tests. All etched ceramic surfaces were examined morphologically using SEM(scanning electron microscopy). Results: Shear bond strength of etching group$(35.89{\sim}68.01MPa)$ had four to seven times greater than no-etching group$(9.53{\pm}2.29MPa)$. The ceramic specimen etched with 4% hydrofluoric acid for 60s showed the maximum shear bond strength$(68.01{\pm}11.78MPa)$. Ceramic surface etched with 4% hydrofluoric acid for 60s showed most retentive surface texture. Conclusion: It is considered that 60s etching with 4% hydrofluoric acid is optimal etching methods for IPS Empress 2 ceramic bonding.

수종(數種) 치과주조용(齒科鑄造用) 금속(金屬)의 독성(毒性)에 관(關)한 연구(硏究)

김기진,박찬운,Kim, Gi-Jin,Park, Charn-Woon 대한치과보철학회 1987 대한치과보철학회지 Vol.25 No.1

This study was performed to investigate the biocompatibility of several dental casting alloys (Gold, Dong Myung A-45, Dong Myung AP-35, Verabond, Rexillium, NPG) employing tissue culture. Fibroblast-like cells derived from the subcutaneous tissue of Sprague-Dawley rat were cultivated in DME medium with the addition of those alloys. Results were assessed by calculating the cell multiplication rate and relative growth rate and by observing the morphology of cells in the presence of the specimens. Gold was indicated to be most biocompatible with fibroblast-like cell. Dong Myung A-45 and Dong Myung AP-35 showed very similar effects on the cells as did Gold. Also there was a decrease in cytotoxicity of the alloys as the concentration of gold increased. Verabond and Rexillium showed a decreased in cell mutiplication rate as compared to low gold alloys. NPG exhibited the most severe cell toxicity among the tested alloys.

우치치질에 레이저조사시 레진과의 결합강도에 관한 연구

조주온,송광엽,박찬운,Cho, Ju-On,Song, Kwang-Yeob,Park, Charn-Woon 대한치과보철학회 1989 대한치과보철학회지 Vol.27 No.2

The purpose of this study is to measure the bonding strength at the enamel and dentin of extracted bovine incisors when they are irradiated by W Nd: YAG, EoQ Nd: YAG, and CW $CO_2$ laser, etched and then attached by composite resin. The laser-irradiated surface, the etched surface after the laser-irradiation and the interface of the treated surface and resin are observed by using scanning electron microscope. The NP Nd:YAG laser is used at the peam power of 207 KW. The EOQ Nd: YAG laser is used at the peak power of 1.15Mk. The CW $CO_2$ laser is used at the energy output of 5W and 10W in enamel; in dentin, at the energy output of 2W. The obtained results were as follows: 1. The shear bond strength of enamel decreased in the following order: EOQ Nd:YAG laser group, NP Nd:YAG laser group, CW $CO_2$ laser groups, unlased group. The unlased group showed a significant difference from EOQ Nd:YAG laser group (P<0.01), NP Nd:YAG laser group (P<0.05), but no significant difference from CW $CO_2$ laser group (P>0.05). 2. The shear bond strength of dentin decreased in the following order: CW $CO_2$ laser group, NP Nd:YAG laser group, unlased group, EOQ Nd:YAG laser group. The unlased group showed a significant difference from CW $CO_2$ laser group (P<0.01), but no significant difference from Nd:YAG laser groups (P>0.05). 3. The scanning electron microscope of enamel revealed irregular microcrack and pore at the surface in the NP Nd:YAG laser group and CW $CO_2$ laser group, but the crackless flat surface in the EOQ Nd:YAG laser group. 4. The scanning electron microscope of dentin revealed obstruction of in most of dentinal tubule and decrease of diameter. 5. The scanning electron microscope of the interface of resin and enamel revealed prominent penetration of resin tag in the EOQ Nd:YAG laser group.

Mandibular Kinesiograph를 이용한 하악운동의 형태와 PRI(Pantographicc Reproducibility Index)와의 비교

최정호,송광엽,박찬운,Choi, Jeong-Ho,Song, Kwang-Yeob,Park, Charn-Woon 대한치과보철학회 1991 대한치과보철학회지 Vol.29 No.1

The purpose of this study is to investigate the correlationship between Pantographic Reproducibility Index(PRI) scores and patterns of mandibular movements by mandibular kinesiograph(MKG) that has been used to diagnose temporomandibular disorders. PRI scores have been measured in normal and symptom groups by tracing Denar mechanical pantograph. Maximum lateral deviation, opening & closing velocity, and clinical rest position of mandibular movements have been analyzed in the same group when the mandible is opened and closed. According to to Helkimo's Dysfunction Index, the students and graduates of College of Dentistry are classified as 6 normal groups and 42 symptom groups. The obtained reslts are as follows : 1. The mean of PRI scores was larger in symptom groups than in normal groups. 2. The mean of maximal laterotrusion in frontal trajectory was larger in symptom groups than in normal groups. 3. There was little significant correlationship observed between PRI scores and patterns of mandibular movements by MKG.

잇솔질이 도재의 색 안정성에 미치는 영향

이임기,정준오,박찬운,Lee, Im-Gi,Jeong, Jun-Oh,Park, Charn-Woon 대한치과보철학회 2002 대한치과보철학회지 Vol.40 No.2

This study is going to compare the degree of color change which occurs in the following two cases of the factors which cause the color change of extra-staining, one is during glazing by the dental technician, the other is tooth brush abrasion which makes the biggest influence on color change. To compare the degree of color change before and after glazing, a sample was made with vintage incisal porcelain No. 59 OPAL(Shofu Inc, Japan), after that it was painted with three colors of porcelain stainers, then the degree of color was measured with a spectrophometer(Model Chromaview 300, Spectoron Tech Co. Korea) after it had been treated with firing only and glazing after firing 40,000-cycle and 80,000-cycle of tooth brush abrasion test were carried out in order to simulate the brushing effect of 4 years and 8 years by using the abrasion tester. The colors were measured before the test, and after the 40,000-cycle and 80.000-cycle operations and the surfaces were examined by SEM. The results of this study were as follows ; 1. The color change before and after glazing was not great enough to have a clinical significance but the orange color was changed more significantly statistically than the blue and light brown(p<0.05). 2. In the case of the color change of stained porcelain by tooth brushing, carrying out staining and glazing with two-times firings resulted in statically less color change than one firing only(p<0.05). 3. In the case of the difference in the stainer's color, the orange color which has higher chroma was statically more sensitive than the blue color(p<0.05) 4. In the case of the color change after the 80,000-cycle abrasion, all showed color change when there was one firing and the orange stainer showed some color change with clinical significance when firings were done two times.

수종의 post와 IPS-Empress Ingot 두께가 전부 도재 수복물 최종색조에 미치는 영향

복원미,최근배,박찬운,안승근,Bok Won-Mi,Choi Keun-Bae,Park Charn-Woon,Ahn Seung-Geun 대한치과보철학회 2004 대한치과보철학회지 Vol.42 No.5

Statement of problem: All-ceramic restorations have been advocated for superior esthetics. Various post and core systems have been used to improve the strength of damaged teeth, but it is unclear whether they affect the final shade of finished all-ceramic restorations. Purpose: The influence of different types of post and core systems on light transmission through all-ceramic crowns was assessed by spectrophotometric analysis. Also the masking effect of different thickness of ceramic ingot was evaluated. Material and Methods : Forty-five sample disks (15mm in diameter) at several thickness(1.0, 1.5, 2.0mm) and value(shade 100, 200, 300) were made in heat pressed ceramic(IPS-Empress). Background specimens simulating gold-alloy cast posts(Type III casting gold alloy), metal posts(Ni-Cr casting alloy) and ceramic posts(CosmoPost) were fabrica-ted. Resin composite(Z250, A3 shade) was used as a tooth substrate reference. For each combination, the change in color was measured with a spectrophotometer. Readings were performed for 2 conditions (1) ability of ceramic to mask the core in relation to its thickness(1.0, 1.5, or 2.0mm) ; (2) influence of post and core types on the final color of the ceramic. Data were recorded according to the CIE $L^*a^*b^*$ systems and color difference($\Delta$E) was calculated. Results: 100 shade ingot: when ceramic thickness was 1.0mm, $\Delta$E value for ceramic post larger than 1 but $\Delta$E value for metal and gold post was larger than 2. For ceramic thickness of 1.5mm, only $\Delta$E value for metal was larger than 2, and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 2. 200 shade ingot: when ceramic thickness was 1.0mm, $\Delta$E value for ceramic post was smaller than 1 but $\Delta$E value for metal and gold post was larger than 2. For ceramic thickness of 1.5 mm, only the $\Delta$E value for metal was larger than 2, and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 1. 300 shade ingot: when ceramic thickness was 1.0mm, only $\Delta$E value for metal was larger than 2 and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 1.5mm, $\Delta$E values for all specimens was smaller than 1. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 1. Conclusion: The final esthetic result of the IPS-Empress glass-ceramic restoration was not affected by the presence of different core materials when the thickness was more than 2.0 mm. When ceramic thickness decreases to 1.5mm, it is advised to take the substrate aspects into consideration. If the ceramic thickness is less than 1.0mm, using the tooth color matched substrate is strongly recommended.