신규 3작용성 메타크릴레이트의 치과용 광중합형 콤포짓트 레진용 단량체로서의 응용 연구

김중곤,정찬문,김민성,김광만,김경남 大韓齒科器材學會 2001 대한치과재료학회지 Vol.28 No.4

Tris[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]methane(THMPM) was prepared easily from triphenylolmethane triglycidyl ether in good yield. As compared with composite resin formulated with difunctional bis-GMA, the physical properties of a newly developed composite resin formulated with trifunctional THMPM was evaluated. Cytotoxicity and acute toxicity of composite resin based on trifunctional THMPM evaluated according to ISO standard method. The depth of cure of the composite resin based THMPM was higher than that of the bis-GMA composite. There were no significant differences in flexural strength and water sorption between the composites resin based on THMPM and bis-GMA. The water-solubility value for the light-activated composite resins formulated with THMPM was much lower than that for a control bis-GMA composite. According to cytotoxicity evaluation, the composite resin based on THMPM showed very mild cytotoxicity with the response index of between 0/0 and 1/0. No acute toxicity of composite resin formulated with trifunctional THMPM was also observed. It is believed that THMPM is promising candidate for application as a photocurable dental composite resin.

치아 수복용 불소함유 glass filler의 제조 및 특성

김대성,최세영,김경남,김광만,김중곤 대한치과기재학회 1998 대한치과재료학회지 Vol.25 No.3

The purpose of this study was the reaching test of restorative glass according to composition. Mixtures of SrF₂, CaF₂and SiO₂were fused in platinum crucible. The glasses were ground and fraction which passed through a 400 mesh (38㎛) sieve were collected. The powder specimens were analyzed by a DTA and XRD. Then powder specimen were inserted to D. I. water with various of dissolution time and composition at 37℃. Fluoride ion, cation release, solubility, and pH change were estimated. It was clear that the glasses were formed except S0.65. In S0.40, Tg, Ts, and Tc were 630, 672, and 813℃ respectively. In initial 0.5 hrs., amounts of released fluoride ion and cation were about 90% of total released amounts and released rate was decreased with dissolution time. Amount of released fluoride ion and cation were increased with decreasing SiO₂ in glass filler. And released rate was decreased rapidly by adding CaF₂. This was caused by structural variation in glass filler. Solubility was similar tendency with ion released. The pH of D.I. water was 4.5. But in intial 0.5 hrs., pH was 8.2∼9.8., and decreased according to dissolution time. This is caused by ionic changing with cation and H* ion.

김치와 한약에 의한 치과용 심미수복재의 변색

김광만,김경남,이상배 대한치과기재학회 1997 대한치과재료학회지 Vol.24 No.1

Dental composite resins have many advantages but still have problems like low strength, hardness and poor color stabilities. Many studies related to color changes have been carried out but there is nothing about color changes by Korean foods and drugs. To evaluate the color changes caused by Kimchi and herb medicines, Aelitefil(Bisco Co., U.S.A.), Veridonfil(Hyosung T&C Co.,Korea), Z-100(3M Co., U.S.A.) and experimentally manufactured materials were chosen and all materials were A2 shade. The specimens(8mm dia., 2mm thickness) were made according to manufacturer's instructions and colors were measured by spectrophotometer(CD35000D, Minolta, Japan) according to CIEL*a*b* system. Then the specimens were immersed in Kimchi and herb medicines at 23℃, dark room and were measured color after 24, 48, 72hours and 7days. The color changes(ΔE) were calulated using ΔE={(ΔL*)²+(Δa*)²+(Δb*)}% equation and statistically tested by Duncans Multiple Range Test, Wilcoxon Test, Kruskal Wallis and Mann Whitney usage test. The results were as follows : 1. The color changes by Kimchi were greater than by herb medicines(P<0.05). 2. L* values decreased and a*, b* values increased by immersion in Kimchi(P<0.05). 3. There were no relationship of changes of L*, a*, b* values in case of treatment immersed in herb medicines. 4. The color changes of Z-11 were greatest among tested materials and those of Aelitefil were least. It was concluded that special considerations were needed to use in oral cavity and to manufacture the new composite resins because it was easily changed by Kimchi.

레이저를 이용한 치과용 도재의 glazing 효과

김광만,김경남 대한치과기재학회 1996 대한치과재료학회지 Vol.23 No.2

Two types of dental ceramics for metal-ceramic system(CeramcoⅡ, VMK 68) and one type of dental ceramic for all-ceramic system(Empress) were choosed and all were A2 shade. Specimens were made by manufacturer's instruction and divided by 3 experimental groups that mechanical polished using Sofu porcelain kit(Polish), furnace glazed using porcelain furnace(Glaze) and laser glazed using CO₂laser(Laser). Controls were roughened by #100 sandpaper. The color changes were measured L*, a*, b*, according to CIELab system by spectrophotometer (Minolta 3500D, Japan) and surface roughness were measured Ra and Rz by surface troughness tester(Surfrecord, Kosaka, Japan). The results were as follows: 1. Only all-ceramic systems (Empress)were glazed by laser but metal-ceramics systems (Ceramco Ⅱ and VMK 68) were cracked by laser. 2. All experimental groups had lower L* value and higher b* value but had no significant difference in a* value compared with control(p<0.05). 3. All-ceramic systems(Empress)had highest L* value and b* value but lowest a* value compared with other systems in all treatment groups(p<0.05). 4. The surface roughness of control were highest in all treatment groups and Empress were lowest in all products(P<0.05). Dental all-ceramic systems had a possibility to laser glazing and L* values were decreased and b* values were increased in polishing, glazing and laser glazing group.

컴포머(Compomer)와 복합레진의 색조안정성에 대한 비교연구

김희재,김광만,김경남 대한치과기재학회 2000 대한치과재료학회지 Vol.27 No.4

Compomer materials have the advantages of glass-ionomer cements and similar physical properties of composite resins. But there were a few studies about the color stability of compomers. In this study, two commercial compomers, Dyract and F2000, and two composite resins, Estelite and Z100, were used. They were stored in 37℃ water bath for 1 week and in 60℃ water bath for another 1 week and then they were aged with 150k1x xenon lamp for 1 week and another 1 week. The original colors just after light cured as the control color were measured by a spectrophotometer according to the C.I.E. L*a*b* Systems, and the colors stored in 60℃ water bath for 1 week, the colors aged with xenon lamp for 1 week in dry and wet condition, the color aged with xenon lamp for 2 weeks in dry and wet condition, were measured by the same method and compared with the control color. The results were as follows. The □E values of dyract after water bath storage and xenon lamp aging were over 10, and the □E values of F2000 after xenon lamp aging were 3.3-6.35. and the □E values of Z100 after xenon lamp aging were 3.3-5.23, and there were not ? E values of Estelite over 3.3 When the thickness of specimen increased the L*, a*, b* values of all material except Dyract were significantly increased(P<0.05), and Compared with dry condition, the L* values were significantly reduced, and the b* values were significantly increased in wet condition(P<0.05). It was concluded that Dyract compomer was not acceptable for and esthetic restorative material in permanent teeth for the color changes were over 10, and F2000 compomer had the color stability similar to the Z100 composite resin.

분무 열분해에 의한 Ba1-xSrxFe12O19계 자성 미립자의 제조 및 특성 변화

김동현,김광만,김경남,최세영,심인보,이용근 大韓齒科器材學會 2004 대한치과재료학회지 Vol.31 No.1

Magnetic particles with alternating magnetic field are expected to be useful as thermoseeds in hyperthermic cancer treatment, since they can be targeted and confined to the cancer site. Hard magnetic ferrites such as barium ferrite and strontium ferrite are good candidates for thermoseeds of hyperthermia because of their great hysteresis loss. In order to verify the effect of Sr-substitution to Ba-site, synthesized Ba1-xSrxFe12O19 microspheres with various compositions through spray pyrolysis followed by sol synthesis using barium nitrate, strontium acetate and iron nitrate. Coercive force was increased with increasing substitution amount of Sr whereas magnetic saturation was almost constant. Spherical microspheres with average diameter of 11.7~17.0 ㎛ were produced by spray pyrolysis at 400~1000℃. The mean size was dependent on the pyrolysis temperature and flow rate of carrier gas. In order to obtain a single phase of SrFe12O19 crystal, the spray pyrolyzed spheres were undertaken subsequent heat-treatment above 1000℃. During the subsequent heat-treatment, however, spherical microspheres were agglomerated because of necking between particles. Further study has to be continued working on synthesis of pure SrFe12O19 crystal by means of improvement of pyrolysis temperature scheme and extend the heating period.

온도변화에 따른 치과용 인상재의 크기변화

김광만,이종석,김경남,신상완 대한치과기재학회 1998 대한치과재료학회지 Vol.25 No.2

Dental impression materials are necessary for prosthodontic treatment and should have some desirable properties that easy to use, reprocuctibility to oral tissue, dimensional stability and compatibility to gypsum materials and additional silicone impression materials are used mostly. All materials have dimensional chage by thermal changes. So, impression materials shrink during cooling from oral temperature(37℃) to room temperature(23℃). 5 kinds of light body of addition silicone materials(imprint Ⅱ(IM), 3M Co., USA; Examix(EM), GC Co., Japan; Extrude(EX), Kerr Co., USA; Contrast(CT), Voco Co., Germany; Perfect(PF), Hankook JP, Korea) were chosen and the cylinderical specimens(6㎜ dia, 12㎜ height) were made and thermal expansion were measured by thermomechanical analyzer(TMA 2940. TA Instrument. U.S.A.) between 23℃ and 37℃. The data were analyzed by Mann Whitney U-Test. The results were as follows : 1. Thermal expansions of impression materials were increased in order to CT>PF≥EM>EX≥IM(p<0.05). 2. Anterior area had more dimensional change than posterior area in same impression materials. 3. Dimensional changes were more than 40㎛ at anterior area but less than 40㎛ at posterior area in all impression materials. In conclusion, thermal expansions of impression materials were significantly different from each other(p<0.05), and anterior area had more dimensional change than posterior area in same impression materials.

인산염계 실리카 매몰재의 성분변화에 따른 티타늄의 주조특성

김광만,은진원,이상배,김경남 대한치과기재학회 1999 대한치과재료학회지 Vol.26 No.2

A large increase in the use of titanium in density is driven by the desire to take advantage of titanium's excellent biocompatibility and its high resistance to corrosion. The development of investments suitable for titanium castings is critical because their mechanical properties are greatly affected by the surface-reacted layer. The purposes of this study were to evaluate the characteristics of Titanium Vest Ⅱ(CO) and experimentally produced four phosphate- bonded SiO₂ investments(EA, EB, EC, ED). A great deal of attention was focused on the influence of investments, such as setting time, compressive strength, casting compatibility, casting defects, surface microhardness and interfacial zone of the cast titanium. The following results were obtained; 1. The setting time of all experimental groups were significantly shorter than control group(p<0.05). 2. Experimental groups were significantly greater than control group in compressive strength of 1hr and 2wks(p<0.05) and there was no significant difference among the experimental groups(->0.05). Compressive strength after 2wks was significantly greater than 1hr in all tested groups(p<0.05). 3. EA was showed the highest casting compatibility and CO the lowest. 4. There was no fin in the casting of all groups. There were small porosities in a dental x-ray inspection of EA. 5. CO was showed the highest microhardness at the distance of 50 ㎛ from the surface. 6. The interfacial zone was composed of four layers in all groups. There was irregular and thick layer in CO. According to these results, titanium is castable with experimentally produced phosphate-bonded SiO₂investments. In addition, there is room for further investigation of investment materials to improve the precise casting of titanium.

복합레진에 대한 표면도표전색재의 효과

김희재,김광만,김경남 대한치과기재학회 1996 대한치과재료학회지 Vol.23 No.2

Although there have been many improvements in physical properties of the composite resin, they did not fulfil the requirements as a posterior restoration. Many researches have been done to improve the property of abrasion resistance and the use of surface penetrating sealants after polishing was suggested. The aim of this study was to evaluate the effects of surface penetrating sealants on the wear and the surface roughness of the composite resins. Three different surface coating penetrating [Fortify(Bisco, U.S.A.), C1, C2(Experimental samples)] and three different hybrid composite resins [Hyosung T&C, VeridonFil-photo(Korea), Aelitefil(Bisco, U.S.A.), Restorative Z-100(3M, U.S.A.)] were used. The Ra values(㎛) were measured by surface roughness tester)Surfcorder, Japan) and in wear test weights were measured with analytic balance(Surfcorius, U.S.A.) before and after the abrasion test. The results were as follows : 1. The surfaces using Mylar matrix showed the smoothest surface(p<0.05). 2. There were no significant differences in surface roughness and wear between uncoated coated composite resins after polishing(p<0.05). 3. There were no significant differences in surface roughness and wear between groups which experimentally composed to have different hardness number(p<0.05). Considered the results, it will be nessessory to develope an improved and hard surface penetrating sealant which can effect the surface of the polished composite resins.

로디움 첨가량에 따른 Au-Ag 합금의 미세조직과 기계적 성질에 관한 연구

김경남,김광만,노학,박정종 大韓齒科器材學會 2000 대한치과재료학회지 Vol.27 No.3

There are solid solution strengthening, precipitation strengthening, dispersion strengthening, grain size strengthening and strain hardening in strengthening mechanism of alloys. Grain size refiners in dental casting alloys were generally high melting point platinum group metals- Ir(iridium), Ru(ruthenium), Rh(rhodium) etc. But they are shown greater segregation in casting ingot because they have relatively large atomic mass and little additional amount than other alloying elements. In this study, 75wt% Au-25wt% Ag was selected basic composition, and then 0.05wt%, 0.1wt% and 0.3wt% Rh was added to a basic composition as a grain refiner. Analytic specimen were made with diameter 5 mm and length 40mm, and tensile test specimens were prepared with conical shoulders. To evaluate Rh effect, changes of microstructure and X-ray diffraction patterns were observed. Tensile strength and micro-Vickers hardness were also measured. In according to Rh content, percentage of dendrite was decreased and disappeared at 0.3 wt% Rh addition. From the result of x-ray diffraction, second phase was not observed. Each value of yield strength was 46.9±6.1MPa(0.00 wt% Rh), 57.5±4.2MPa(0.05 wt% Rh), 59.8±5.3 MPa(0.1 wt% Rh)and 66.2±6.5 MPa(0.3wt% Rh). From these result, it was shown that yield strength, tensile strength and micro-Vickers hardness were increased with increasing Rh content. In conclusion, addition of Rh to 75wt% Au-25wt% Ag alloy improved microstructure and mechanical properties.