치과용 콤포짓트 레진의 중합수축 응력

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

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).

티타늄 표면처리에 따른 조골세포의 반응

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

It is well known that surface modification of titanium for implant has been shown to improve the adhesion, migration and differentiation of adjacent cells and tissues. This study presented the results of an experimental study on the interaction between MC3T3-E1 (mouse calvarian osteoblast cell line) cells and cp-titanium treated by thermal oxidation at four different temperatures after TiO2 blasting and NaOH treatment, which could provide the benefits of surface roughening and favorable oxide layer formation. No heat treatment group was used as a control. Cell interactions were studied using the combination of phase contrast microscope and scanning electron microscope. Potential cytotoxicity was tested by MTT assay. The response of osteoblast cells was different according to the condition of surface modifications. Thermal oxidation at 600℃ showed the best early cell attachment and calcium nodule formation compared to other groups. Thermal oxidation at 800℃ showed the worst cell attachment and proliferation. In general, osteoblast cells were attached to accompanying the formation of cellular process, spreaded and differentiated on the specimen surfaces. Calcium nodules were formed on the surface after these cells were developed multiple cell layers. These early osetoblast/titanium interactions might play a critical role in the osteoinduction stage of osseointegration. There was no statistically significant difference in cytotoxicity among the heat treated surfaces from the MTT assay(p>0.05). The results of microstructure analysis of the characterized cp-titanium surface of this study will be published separately.

유기용매에서 치과용 콤포짓트 레진의 시효처리에 따른 표면조도 및 색 변화

임범순,김철위,문현정 대한치과기재학회 1999 대한치과재료학회지 Vol.26 No.1

The purpose of this study was to evaluate the degree of color stability and examine the surface change of esthetic restorative materials in various organic solutions. Ten esthetic restorative materials were used : three chemical-cured composite resins(HPC, PAS, and PAL), four light-cured composite resins(CHA, Z100, AEL, and FLO), three light-cured polyacid modified composite resins(HYT, DYR, and COM). Specimens were prepared as disks of 14mm in diameter and 1.2mm in thickness. After polymerization, specimens were immersed in six different solutions(distilled water, artificial saliva with mucin, 0.1 mole acetic acid solution, 10% hydrogen peroxide solution, and 50% and 75% ethanol) for 1,7,14,21,28,56,84,112, and 140 days. The specimens were maintained at 37℃ throughout the study. Color was measured by CIE L*a*b* against to CIE standard illuminant C reflected on spectrophotometer(CM-3500d, Minolta, Japan.) with specular component exclusive(SCE). After various treatments, the surface of specimens was examined by Surface Roughness Tester(Surtronic 3P, Rank Taylor Hobson Ltd., England.). From the experiment, the following results were obtained. In distilled water, specimens showed an acceptable color stability except for CFS. The water hardening glass ionomer cement, CFS, showed the highest color change(△E>5.0). Color stability of specimens in artificial saliva with mucin was similar to that in distilled water. CFS and KTM showed high color change(△E>5.0) and it would not be acceptable in the clinical situation. In acetic acid solution, all of the glass ionomer cements and compomer specimens showed high color change due to the dissociation of metal-polyacrylate by chemical reaction with H+ ions. CFS, FLC, and FLT showed high color change in ethanol. Color change of specimens in 50% ethanol was higher than that in 75% ethanol. 10% hydrogen peroxide solution resulted in high color change for chemical-cure glass ionomer cements and destroyed the specimens. FLC and CPG showed high color change due to oxidation of residual reaction accelerator and inhibitor by hydrogen peroxide.

은, 동 및 팔라듐이 치과용 저금계 합금 및 은-팔라듐계 합금의 표면경도, 황이온에 의한 변색 및 부식저항성에 주는 영향 : Ⅱ.Experimental Low Gold Based Alloys Ⅱ. 실험용 치과용 저금계 합금

임범순,문현정,김철위 대한치과기재학회 1999 대한치과재료학회지 Vol.26 No.2

Nine experimental low gold based alloys (Au = 20 %) were prepared with various concentrations of Pd, Ag, and Cu. Experimental alloys were divided into three groups : casted alloys, quenched alloys subsequent to solution treatment, and aged alloys subsequent to solution treatment. Microstructure of alloys was examined by Optical microscope and SEM with EDXA, and surface hardness of alloys was measured by Vickers' hardness tester. Color changes and anodic polarization curves of alloys in the modified Fusayama's artificial saliva with various S² concentrations (0.01, 0.10, 0.50, 1.00, and 5.00 mM/ℓ) were evaluated by Spectrophotometer and Potentiostat. With an increase of Pd concentration in experimental alloys, color change (ΔE) of alloys was significantly decreased and surface hardness was moderately increased, but it had surprisingly little effect on the anodic polarization curves (p>0.05). Color change (ΔE) and surface hardness were increased with a decrease of Ag/Cu ratio in experimental alloys, but anodic polarization curves did not change significantly (p>0.05). Color changes of the quenched alloys was lower than those of the aged alloys. Corrosion potential of alloys was not affected by heat treatments, but current densities were affected at high potential (>400 mVSCE). Significantly higher current density of the aged alloys, compared to the quenched alloys, could result in server corrosion. The surface hardness of the casted alloys was apparently greater than that of quenched alloys. In SEM and EDXA analysis, it was observed that Pd was precipitated in the Cu-rich phase and Au migrated to the Ag-rich phase.

인공타액에서 염소이온과 황이온 농도가 치과용 귀금속계 합금의 변색 및 부식저항에 주는 영향 : 1. 시판 치과용 귀금속계 합금 1. DENTAL COMMERCIAL NOBLE METAL BASED ALLOYS

임범순,문현정,김철위 대한치과기재학회 1998 대한치과재료학회지 Vol.25 No.2

The object of this study was to study effect of Cl- and S²- ions on tarnish and corrosion resistance of dental noble metal alloys in the artificial saliva. Twenty-four commercial dental noble metal based alloys(five for high-Au based alloys, seven for low-Au based alloys, four for Pd-based alloys, and eight for Ag-Pd based alloys) were investigated by the Potentiostat and the Spectrophotometer. Modified Fusayama's artificial salivas with various concentrations of Cl- ion(1.22, 12.22, 24.44, and 61.10 mM/ℓ) and S²- ions(0.01, 0.10, 0.20, 0.35, 0.50, 1.00, 5.00, 10.0, and 20.0 mM/ℓ) were used as electrolytes for test. From the experiments, the following results were obtained. Concentration of Cl- ion in artificial saliva did not in fluence the potentiodynamic polarization curves for dental noble metal alloys. On the other hand, concentration of S²- ion in artificial saliva strongly influenced the potentiodynamic polarization curves for dental noble metal alloys ; corrosion potentials were decreased up to 500 mV and current densities were increased by 100 times. In color change measurements after potentiodynamic polarization curve test, the values of ΔE for high-Ae and Pd-based alloys were increased as the concentration of S²- increased up to 1.00 mM and then were reached a plateau at higher concentration of S²-. For low-Au and Ag-Pd based alloys, the values of ΔE were drastically decreased as the concentration of S²- increased up to 1.00 mM and then were reached a plateau at higher concentration of S²-. By determining the color of an alloy before and after exposure to a test solution, the color changes were ranged of 4∼6 for high-Au and Pd-based alloys and 20∼35 for low-Au and Ag-Pd based alloys.

치과수복용 글라스 아이오노머 시멘트의 개발

임범순 大韓齒科器材學會 1995 대한치과재료학회지 Vol.22 No.2

The purpose of this study was to synthesize the experimental restorative glass ionomer cement by change of glass component and fusing temperature. Mixtures of Al₂O₃, SiO₂, CaF₂, NaF, AlPO₄and SrCO₃were fused in recrystallized alumina crucibles. Initially 6 mixtures were fused at 3 different temperatures (1050℃, 1200℃, and 1350℃), but 17 groups (exception of GI-6C) were tested. The glasses were ground, and the fraction which passed through a 44㎛ sieve was collected. The glass powders were analyzed by a differential thermal analyzer and a x-ray powder diffractometer. A chemical-cured glass ionomer cement (FI-A) and a light-cured glass ionomer cement (FI-B) were used as control group. The powder/liquid ratio for cement formation was 2.3g/0.8g. Compressive strength of specimens was measured by a Instron universal testing machine. Surface hardness of specimens was evaluated by Vickers hardness tester, and fluoride ion release from specimens was estimated by the fluoride ion electrode and standard solutions. Solubility of specimens in 0.1 M lactic acid solution was also measured. From the experiment, the following results were obtained. 1. Compressive strength, surface hardness, and fluoride release of experimental groups which were fused at 1050℃ were greater than those of the groups fused at 1350℃. Experimental groups which were fused at 1350℃ however, exhibited the lowest solubility in lactic acid solution. 2. GI-1 group base cements showed better physical properties than the other groups. Especially, the results showed that GI-1B base cement was comparable in physical properties to Fuji Ⅱ glass ionomer cement except for short working time. 3. It was observed that SrCO₃would act as a radio-opacifier in GI-2, GI-3, GI-5 and GI-6 base cements. 4. GI-3A and GA-6B groups were unsuitable for clinical use since it base cements dissolved in lactic acid solution and exhibited a delayed setting reacting respectively. GI-6A Group was unsuitable since it base cement dissolved in lactic acid as well as exhibited a delayed setting reaction.

광도 및 시효에 따른 치과용 콤포짓트 레진의 물성에 관한 연구

임범순,김철위 대한치과기재학회 1997 대한치과재료학회지 Vol.24 No.2

Eleven kinds of dental composite resins were used in this study, which were three chemical curing resins and eight light curing composite resins. The initial polymerization degree of the light-curing composite resins was controlled by altering the light intensity of the curing unit. Four different relative light intensities(25, 60, 90, and 100%) were used. Specimens were aged various conditions ; four different aging periods(1, 7, 14, and 28 days), four different aging environments(water, artificial saliva, ethanol, and 0.1 M acetic acid solution), and two different aging temperatures(36 and 60℃). Then, compressive strength and fracture toughness were measured by using Instron Testing Machine. Solubility and sbsorption of water wer evaluated by measuring the weight changes. From the experiment, the following results were obtained : 1. In light-curing composite resins, the higher reative light intensity used for curing, the higher compressive strength, fracture toughness, and solubility resistance were observed. 2. The highest compressive strength was obtained with the groups of aged in air, the highest fracture toughness was obtained with the groups of aged in 0.1 M acetic acid solution gave rise to significant effect on compressive strengtth for with the groups of aged in ethanol. 3. The groups aged in ethanol showed significant variation on compressive strength with increasing of aging period. Aging treatment in 0.1 M acetic acid solution gave rise to significant effect on compressive strength for the chemical-cured composite resins. 4. In chemical-curing composite resins, no significant difference was observed between groups aged in 36℃ and groups aged in 60℃.

치과용 아말감과 상아질의 결합강도에 관한 연구

임범순,김철위,김명국,백기석 대한치과기재학회 1996 대한치과재료학회지 Vol.23 No.1

The purpose of this study was to evaluate the shear bond strength of amalgam to dentin treated with the various bonding agents and to examine the failure mode after bond test. Four kinds of dental amalgam and six kinds of dentin bonding agents were used in this study. Copalite varnish was used for control group. The extracted human molars were mounted in a self-cured acrylic resin and the nonocclusal surface of the crown was exposed by grinding. A well-fitted wax mold was placed on the dentin surface and dentin adhesives were applied according to the manufacturer's instructions before condensing the amalgam. After condensation of the amalgam, specimens were stored at 37℃ and 100% relative humidity for 24 hours to complete hardening process. Specimens were aged in a deionized water at 37℃ for 24 hours, then tested in shear on a Instron universal testing machine at a cross-head speed of 0.2mm-min. From the experiment, the following results were obtained: 1. The bonding agents which included NTG-GMA, showed a low shear bond strength. It was observed that the fracture modes between bonding agents and amalgam were adhesive failure. 2. The bonding agents which included 4-META, showed a high shear bond strength. Some fracture modes between bonding agents and amalgam showed cohesive failure, although many fracture modes showed adhesive failure. 3. For the bonding agents which included a phosphate ester system, the shear bond strength showed large scattering depending on bonding agent. When specimens showed a high shear bond strength, the mixed (adhesive/cohesive) failure mode between bonding agents and amalgam were observed. 4. BDX produced a low shear bond strength. It was observed that the control group(CPL) was' not effective for amalgam bonding agent.

치과용 합금의 부식성에 관한 연구

임범순,이용근,윤숙진,김철위 大韓齒科器材學會 1995 대한치과재료학회지 Vol.22 No.1

Corrosion of dental alloys in the oral cavity can affect the mechanical, esthetic properties and efficiency of metallic restorations, and has great influence upon the local and systemic health of patients. The purpose of this study was to clarify the corrosion behavior of various dental alloys, and to measure the galvanic currents between dissimilar alloys. Fifty-eight kinds of dental casting alloys such as twenty-nine high gold alloys, ten low gold alloys, fourteen silver-palladium alloys, five base metal alloys, and twenty kinds of ceramic alloys such as seventeen noble metal alloys, three base metal alloys, were used as the experimental alloys. Modified Fusayama's artificial saliva titrated to pH 6.7 with phosphoric acid was used as an electrolyte. The specimens were immersed in the modified artificial saliva of 37℃. The rest potentials, anodic polarization curves, corrosion potentials, and galvanic currents were measured by using the potentiostat / galvanostat and zero shunt ammeter. From the experiment, the following results were obtained : 1) The gold based alloys showed the high rest potentials and the low current densities within experimental potential range. 2) The rest potentials and the current densities of the palladium-based alloys were influenced by the content of platinum, palladium, and silver. 3) In the nickel-chromium base alloys, the formations of passivation film were influenced by chromium content. The copper-aluminum alloy showed very high current density which was more than 150 mV . 4) The corrosion potentials of ceramic alloys were lower than those of dental casting alloys, but the trend of anodic polarizations were generally similar to the other alloys. 5) The amount of galvanic current and the polarity in the bimetallic galvanic cell could not be predicted considering only the alloy composition. The galvanic current decreased while the measuring time passed, but flew continuously.