시효처리와 마모체가 치과용 콤포짓트 레진의 마모에 주는 영향

김승헌,임범순,문현정,이용근,김철위 大韓齒科器材學會 2001 대한치과재료학회지 Vol.28 No.4

Over the last decade, the use of posterior resin composites has grown considerably. Wear resistance of restorative materials is important for clinical longevity, esthetics, and resistance to dental plaque. The purpose of this study was to evaluate the effect of artificial saliva and 75% ethanol solution on the wear resistance of composite resins by measuring the amounts of wear, and compare the effect of antagonistic materials on the wear resistance of composite resins. Four universal composite resins (Z100, Aelitefil, Spectrum, and Unifill F) and two condensable composite resins (Surefil and Synergy Compact) were measured. Cylinder type specimens were light-cured for 40 sec on the wear surface, and 20 sec on each side surface. The surface for wear testing was polished by 600 grit SiC paper. Three different antagonistic materials (600 grit SiC paper, amalgam, and procelain) were used as an antagonist for 2-body wear test. After speciments were aged in 37℃, artificial saliva and 75% ethanol solution for specific periods (1 day, 1 month and 2 month), 2-body wear testing was performed by the FRP-2000 friction tester with applying 500 g load (80 kPa) to the specimen. The wear test was performed for 10 min and 30㎖ distilled water was used as lubricant. Amount of wear was measured by microscopic measuring device of Micro Hardness Tester in 0.1㎛ scale. There was significant difference in wear resistance of composite resins (p<0.05). Composite resins with filler content below 59 vol.% showed higher wear resistance that composite resins those with filler content above 62 vol.%. In composite resins from 1 day to 1 months (p<0.05). On the contray, the wear amounts of groups which filler fraction were above 62 vol.% did not show any significant differences with increasing aging period (p>0.05). In 1 day aged groups, the wear amounts of the groups aged in 75% ethanol solution were more than those of the groups aged for 1 month (p=0.045) and Spectrum group aged for 2 month (p=0.006). Amounts of wear were significantly decreased with changing antagonist from 600 grit SiC paper to amalgam or porcelain (p<0.05).

치과용 글라스 아이오노머 시멘트의 압축, 간접인장 및 전단 결합강도에 관한 연구

김철위,이용근,임범순 서울대학교 치과대학 치과생체재료학교실 1994 치과생체재료학 논문집 Vol.2 No.1

The purpose of this study was to evaluate the compressive strength, diametral tensile strength and shear bond strength of the glass ionomer cements and to compare strengths of the glass ionomer cements independent of their type. The present study utilized one brand of dental zinc phosphate cement and twelve brand of dental glass inomer cements. The load at failure was measured using a Instron universal testing machine (Instron Model 1122), with crosshead speed of 0.05㎝/min. for compressive and diametral tensile test, 0.02 ㎝/min. for shear bond test. From the load at failure, the strength of the specimen could be calculated. Testing of compressive strength, diametral tensile strength, and shear bond strength were carried out at 24 hours and specimens were maintained in distilled water at 37°±2℃ just prior to testing. From the experiments, the following results were obtained; 1.The glass ionomer cements presented a wide variance of compressive strengths. The light-cured glass ionomer cements showed higher compressive strength than self-cured glass ionomer cements. 2. No significant difference (P<0.05) in the diametral tensile strength was observed among self-cured glass ionomer cements. On the contrary, the light-cured glass ionomer cements showed 3∼4 times higher dimetral tensile strength than the self-cured cements. 3. The glass ionomer cements showed a good shear bond strength to dentin.

상아질 표면처리제 및 결합제가 레진강화형 글라스 아이오노머와 상아질의 전단결합강도에 주는 영향

김용대,이용근,임범순,김철위 대한치과기재학회 2000 대한치과재료학회지 Vol.27 No.4

Resin-modified glass ionomers (RmGIs) have been widely used and are recommended for restoring cervical lesions that include enamel and dentin margins, and for caries-prone patients because of the possible anticariogenic effect of fluroride. The purpose of this study was to evaluate the shear bond strength of two resin-modified glass ionomers to dentin using four different dentin surface treatments and two one-bottle bonding agents. Human dentin was pretreated with 35 % phosphoric acid, 10 % citric acid and 3 % ferric chloride, 10 % polyacrylic acid and EDTA 3-2 solution, and was applied with One-Step and Single Bond. Two resin-modified glass-ionomers, Fuji Ⅱ LC(FLC) and Vitremer (VTM), were then adhered to the dentin. After 24 h in distilled water at 37 ℃ the shear bond strength between the resin-modified glass-ionomers and the pretreated dentin was measured with an Instron at a crosshead speed of 0.5 mm/min and the dentin-dentin bonding agent-RmGI interface of the specimen was observed by SEM. From the experiment, the following results were obtained : 1.For the dentin treated only with surface treatments except EDTA 3-2 solution, the shear bond strength of resin-modified glass ionomers to dentin was statistically significant higher than that of resin-modified glass ionomers to dentin treated with dentin surface treatments (p<0.05). 2.For the dentin applied with dentin bonding agents subsequent to pretreatment with dentin surface treatments, the shear bond strength of resin-modified glass ionomers to dentin was statistically significant higher than that of resin-modified glass ionomers to dentin treated only with dentin surface treatments (p<0.05). 3.When the specimens were applied with One-Step or Single Bond subsequent to four different dentin surface treatments, the shear bond strength of resin-modified glass ionomers to dentin was not statistically different between One-Step and Single Bond (p<0.05). 4.With applications of dentin bonding agent, 35 % phosphoric acid or 10 % citric acid + 3 % ferric chloride solutions were found to be the most effective in improving bond strength to dentin, followed by 0.5 M EDTA 3-2 solution and 10 % polyacrylic acid solution. 5.From SEM observations, 10 % polyacrylic acid solution did not completely remove the smear layers, but 35 % phosphoric acid, 10 % citric acid + 3 % ferric chloride, and 0.5 M EDTA 3-2 solution completely removed the smear layers so that could form resin tag.

치과용 알지네이트 인상재의 국산화 및 개량에 관한 연구 : Ⅱ. 불소 화합물 첨가 후 특성 변화 Part Ⅱ. The Effects of Fluoride Incorporation on the Properties

이용근,임범순,김철위 大韓齒科器材學會 2002 대한치과재료학회지 Vol.29 No.3

The goal of this study was to develop dental alginate impression materials that is proper for domestic usage conditions. After incorporation of additional techniques into this material to make multifunctional impression materials, this final product can be commercialized. In the first year of this study, although the characteristics were different by the viscosity of sodium alginate, two formula for dental alginate impression materials were determined, which contain sodium alginate, calcium sulfate, diatomaceous earth, borax, magnesium oxide, potassium chloride, sodium acetate, sodium phosphate, zinc fluoride and zinc oxide (WM₃, WM₄, WH₃ WH₄). New technique tried in the second year was the fluoride incorporation to deliver fluoride on the tooth surface during impression procedure. Four methods of fluoride incorporation were tested. Materials were mixed with distilled water, or 100-ppm fluoride solution. 1 or 2% sodium fluoride, or 1% stannous fluoride was incorporated into the powder. The fluoride-containing materials were mixed with distilled water. Fluoride release, compressive strength, elastic modulus, flexibility, recovery form deformation and setting time were determined. As the results, fluoride release was increased after incorporation of fluoride into water or materials, and the released amount was 0.762~14.76ppm. Sodium fluoride or stannous fluoride incorporation resulted in higher fluoride release than the control group (p<0.05). Incorporation of fluoride into alginate impression materials may be efficient in releasing fluoride without having any deleterious effect on the properties of material. Additional study on the method that can enhance the compatibility with gypsum products was performed. All compositions reproduced 50 ㎛ line for 25 ㎜, and immersion of impression into a 2% potassium chloride solution resulted in better surface quality. From the results, these compositions can be used to make commercial dental alginate impression material, however development of additional commercialization procedure is needed. Domestic sodium alginate should be developed to down the price of ingredient materials.

치과용 알지네이트 인상재의 국산화 및 개량에 관한 연구 : Ⅰ. 조성이 특성에 주는 영향

이용근,임범순,김철위 대한치과기재학회 2001 대한치과재료학회지 Vol.28 No.3

Dental alginate impression materials have become widely used to take study impression for orthodontic and other purposes and, to a limited extent, have been applied in inlay, crown and bridge procedures. The alginate impression products have good elastic properties and compare well with the agar materials. The final purpose of this serial study is to develop a domestic dental alginate impression material which is proper for use in Korea. The final purpose of this first year study was to find a proper composition of alginate impression material, which shows appropriate mechanical properties and high biocompatibility. Several kinds of experimental alginate impression materials were prepared by mixing sodium alginate, calcium sulfate dihydrate, diatomaceous earth as filler, borax, magnesium oxide, potassium chloride, sodium acetate, sodium phosphate, zinc fluoride and zinc oxide in varied proportions. Texture of powder and mixture, flexibility, recovery from deformation, setting time, compressive properties, compatibility with dental stone, reproduction of detail and cytotoxicity by MTT assay and neutral red inhibition zone of mixed experimental and commercial alginate impression materials were tested according to the specifications of Korean Food and Drug Administration, Korean Dental Association No. 8, American Dental Association No. 18 and International Standardization Organization 1563 (1990). From this study, proper compositions of experimental alginate impression material which showed flexibility of 5∼20% (in accordance with the specification), and proper setting time of 1.5∼5 minutes was found. Although the property of recovery from deformation was lower than that of the specification, these values were similar to those of commercial alginate impression materials. The compressive strength was in accordance with the specification of more than 0.35 Mpa. Some compositions showed proper detail reproduction. Cytotoxicity was not different regardless of the composition, and was similar to those of commercial materials. From the above results, two promising compositions were determined to be used as the basic composition for making a domestic alginate impression material. On this result, beneficial properties of fluoride release, reduced dust production and sufficient antibacterial effect will be added before marketing.

치과용 콤포짓트 레진의 적정중합을 위한 최소 광조사 시간 평가

임범순,이용근,김철위,최기열,이중배 大韓齒科器材學會 2004 대한치과재료학회지 Vol.31 No.1

The aim of this study was to estimate the minimum irradiation time for dental composites using a dynamic mechanical analyzer (DMA) and FT-IR. Six commercially available dental composites with A3 shade were tested: Heliomolar RO (Vivadent, Liechtenstein), Charisma (Kulzer, Germany), Herculite XRV Enamel (Kerr, USA), Aelitefil (Bisco, USA), Z100 (3M, USA), and Z250 (3M, USA). Storage modulus was measured by using DMA (StressTech Rheometer, Rheologica Instrument, Sweden) with fast oscillation mode (1 Hz). After disk-type (4 ㎜ ?1 ㎜) samples were irradiated with 500 mW/cm2 for 1, 2, 3, 4, 5, 10, 15, 20, and 30 s, storage modulus was recorded continuously for 60 min. Degree of conversion was also measured using FT-IR spectroscopy (FTS-165, Biorad Win-IR, Perkin-Elmer, USA) at 60 min after irradiation with same curing condition as DMA test. Sample irradiated with 500 mW/cm2 for 120 s was used as a control. The average of results for five specimens was compared using Tukey multiple comparison test (p=0.05) and the minimum irradiation time of composites was determined. The minimum irradiation time to get adequate polymerization was different depending on the dental composites. Both Z100 and Z250 require short irradiation times (5 s) and Charisma requires long irradiation time (15 s).

레진기질과 생체활성 필러에 따른 콤포짓트레진의 특성

이용근,임범순,김철위 大韓齒科器材學會 2003 대한치과재료학회지 Vol.30 No.2

In dentistry, since composite resins are used to restore teeth, their chemical and physico-mechanical characteristics should be similar to those of natural tooth. The mineral phase of bone and teeth is mainly hydroxyapatite. Therefore, synthetic hydroxyapatite would seem a good choice as an inorganic filler to he used in dental restoration or bone implant. The purpose of this study was to gain more insight into the possibility of the bioactive filler incorporated composite resin as restorative material, limns; material or pulp capping material through the evaluation of mechanical properties and cytotoxicity. Bioactive fillers such as apatite-wollastonite (AW) glass ceramic, bioglass (BG) and hydroxyapatite (HA) powders, and conventional glass fillers were incorporated into light-curing resin matrices composed of Bis-GMA and TEGDMA (6:4 by wt.), Bis-GMA and HEMA (6:4 by wt.), Bis-GMA, HEMA and TEGDMA (3:4:3 by wt.). and UDMA and TEGDMA (6:4 by wt.). Compressive, diametral tensile and flexural strength of light-cured specimens immersed in 37℃ DW for 24 hours was measured. Cytotoxicity by MTT method was also evaluated. When Bis-GMA and TEGDMA mixture was used as the resin matrix, compressive, diametral tensile and flexural strength of bioactive filler incorporated composite resin was 17.72∼128.22 ㎫. 39.57∼84.46 ㎫ and 21.35∼57.36 ㎫, respectively. When Bis-GMA and HEMA mixture was used as the resin matrix, BG filler incorporated composite resin did not cure, and the highest compressive and diametral tensile strength of bioactive filler incorporated composite resins was 40.24 ㎫ and 35.30 ㎫, respectively. When Bis-GMA, HEMA and TEGDMA mixture was used as the resin matrix, BG filler incorporated composite resin did not cure, and three strength values were highest after incorporating HA filler. When UDMA and TEGDMA mixture was used as the resin matrix, compressive, diametral tensile and flexural strength of bioactive filler incorporated composite resin was 38.61∼137.31 ㎫, 32.59∼110.47 ㎫ and 17.10∼48.70 ㎫, respectively. Generally, cytotoxicity of bioactive filler incorporated composite resin was higher than those of conventional glass filler incorporated resins. From the above result, mechanical properties of bioactive filler incorporated composite resins made of conventional Bis-GMA, UDMA and TEGDMA matrices were moderate; however, those of HEMA-incorporated matrices were low.

치과용 인산칼슘계 충전 및 재생재료 개발(Ⅰ)

이용근,임범순,김철위 대한치과기재학회 2001 대한치과재료학회지 Vol.28 No.3

Because calcium phosphate materials including hydroxyapatite are bioactive and exhibit good biocompatibility, these compositions are actively tried as the hard substituting materials. At the beginning of the development of the calcium phosphate materials, these materials were used as sintered ceramics. After then, plastic calcium phosphate cements were developed to make the shape of the material directly at the site of application. Reports on the dental calcium phosphate materials can be assorted into some categories; development of root apex sealing material or canal sealer, development of pulp capping material or cavity liner, or the reinforcement through addition of resin materials. Studies on the biocompatibility and drug delivery system may be other categories. The final purpose of this study is the development of dentine substituting materials based on calcium phosphate, which is highly biocompatible with the tooth pulp and additionally can stimulate or accelerate the dentine formation. In this preliminary study, PMVE-Ma (polymethy1 viny1 ether-maleic anhydride), HPMC (hydroxypropy1 methy1 cellulose), acrylic resin and acrylic-maleic copolymer was added into the PBS (phosphate buffered solution) to optimize the mechanical and chemical properties of calcium phosphate cement. From this study, AC-1 (4:1 mixture of cement powder and resin powder mixed chemical cure acrylic resin solution) showed the highest diametral tensile strength after storage in 100 % relative humidity for 24 hours, and AM-3, AM-2 (4:1 mixture of cement powder and resin powder mixed with 40 or 30 % acrylic-maleic copolymer) followed. The ranking of compressive strength from the highest in the same condition was AC-1, AM-2 and HP-4 (cement powder mixed with 15 % PMVE-Ma in DW). HP-4 showed the highest diametral tensile strength after storage in normal saline for 24 hours, and AC-1 and AC-2 (9:1 mixture of cement powder and resin powder mixed chemical cure acrylic resin solution) followed. The ranking of compressive strength from the highest in this condition was AC-1, HP-4 and HP-6 (cement powder mixed with the 1:1 mixture of 2 % HPMC in DW and 15 % PMVE in DW). From the point of the mechanical properties, AC-1, HP-4, AM-3 and AM-2 seemed proper for dentine filling material. Addition of resin materials did not influence on the speed and ratio of hydroxyapatite formation. From this study, appropriate compositions based on calcium phosphate for dentine filling materials can be found.

치과용 콤포짓트 레진의 중합수축 응력

임범순,이용근,김철위 대한치과기재학회 2001 대한치과재료학회지 Vol.28 No.2

배양조건에 따른 치수세포 RPC-C2A의 특성 : 배양용기 및 BMP 처리 Culture Ware and BMP Treatment

이용근,임범순,김철위 大韓齒科器材學會 2003 대한치과재료학회지 Vol.30 No.4

Odontoblasts are highly differentiated cells aligned at the periphery of the dental pulp. Pulp tissue responds to injury by generating reparative dentine elaborrated by odontoblast-like cells that differentiated from pulp cells. In vitro, dental pulp cells cultured under certain conditions are able to express typical markers of cell differentiation; however, no culture sysem can simulates clinical pulp response. The purpose of this study was to evaluate the effect of culture ware and BMP on the seeding. growth sne differentiation of pulp derived cell line, RPC-C2A. Large pore-sized PET membrane (0.4 ㎛, Cell Culture Insert, BD Science, USA), rhBMP-4 (R & D Systems, USA) and polystyrene modified by vacuum-gas plasma treated culture surface (Primaria, BD Science, USA) were tested. RPC-C2A cells are maxillary incisor pulp cells from male Wistar rats (Kasugai el al., 1988). Cells were cultured on a traditional polystyrene culture ware (PS), transparent PET membrane (MI), Insert + rhBMP-4 (20 ng/ml, MB), and Primaria culture ware (PM) up to 21 days. Culture media was 10% FBS added DMEM with 10 mM β-glycerophosphate, 10^-8 M dexamethasone, 50 ㎍/ml ascorbic acid and 50 mM sodium fluoride. Formation of multilayered cell layer and mineral nodule was determined with a phase contrast microscope and EDXA. There were no differences in cell attachment and growth rate among four culture conditions up to three-days culture. Multilayered cells were observed after six-days culture, and mineral nodules were observed in MB condition after seven-days culture. After nine-days culture, mineral nodules were observed in PS, and new nucleation of mineral nodules was prominest in MI and MB conditions. Exfoliation of cells from the dish was observed in PS after 13-days culture, and vaeuoles were formed in MI after 19-days culture. After 21-days culture, cell death was accompanied by increase of mineral nodules in MB. Growth and development of pulp cells were influenced by the culture ware and BMP. In MB condition, the duration for the formation of multilayered cells and mineral nodule was shortened compared to other conditions.