To fabricate dental ceramics restorations development of a novel CAM system using RP layering method was attempted. Composite slurry with acrylic resin and alpha-alumina particle was layered and cured by UV laser. The fabricated object was heated to remove resin, and then ceramic crown was obtained by sintering.

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我々は，オールセラミッククラウンのコーピングを特別な機器や複模型を使用せずに，短時間で容易に製作可能な焼成陶材法を開発し，臨床応用の可能性があることを報告した．第2報では製作時間の大幅な短縮を可能とした．強度については臨床応用に許容される値であった。さらに強度を改善する必要が明らかとなった．そこで今回は，強度を大きくすることを目的として検討を行った．

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部分床義歯の良好な経過を得るには，義歯の動揺を抑制することが重要である．そのためには，多くの場合，支台歯のクラウンと義歯フレームワークの精密な適合を与える必要がある．本研究は，支台歯と支台装置の精密な適合性とメタルフレーム製作上の合理性を兼ね備えたキャストオン法について，臨床応用するための基礎的データを得ることを目的とし，鋳型温度の違いによる鋳造界面への影響を検討した．

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Electrolyzed water obtained by electrolyzing dilute saline solution has been widely used for sterilization and disinfection owing its excellent bactericidal activity. Corrosion behavior of metals was examined in the water in the present study. The metals involved pure aluminum, pure copper, rolled steel, 18-8 stainless steel and zinc-plated steel. The specimen was prepared by cutting each sheet into rectangular plate 1.5x1.5x0.5mm. The specimen was immersed in 30ml testing water, strong acid electrolyzed water, neutral electrolyzed water and tap water for 3, 6, 12 and 24hr. The strong acid water was severely corrosive to the metals. The neutral water showed much less corrosiveness similarly to tap water except for the rolled steel which was tarnished after 3hr immersion leaving brownish precipitates.

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We have been carrying out research works to develop Pd-free dental noble alloys from the viewpoint of stable supply of precious metal alloys for crown and bridge restorations to the dental services. Cyclic voltammetry (CV) was carried out on experimental Ag-Au-Pt-Cu low-gold dental alloys to examine their corrosion resistance in a 0.9% NaCl solution. It was found that the Au/Ag atomic ratio is a controlling factor of corrosion resistance.

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本研究は純チタンおよびチタン合金の疑似口腔内環境における腐食挙動を調査したものである。純チタンおよびチタン合金は、ミュータンス菌が産生する酸と500ppm程度のフッ素が混在する環境では腐食する可能性があることが示唆された。

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The alloy showed the maximum age-hardenability at the ageing temperature of 400. The hardness drastically increased to reach the maximum value, and then decreased continuously with ageing time. By ageing at 400 for 50 min when the maximum hardness value was obtained, the alpha 0 phase was separated into the alpha 1 and AuCu I phases in the matrix, and the fine InPd precipitates containing Zn were formed at the grain boundary. By prolonged ageing until the hardness decreased significantly, the matrix was replaced by the coarse lamellar structure composed of the AuCu I phase containing Pd and Zn and the Ag-Au-based alpha 1 phase of Cu-, Pd- and Zn-depleted. The hardness increase at the early stage was caused by the nucleation of the AuCu I phase in the alpha 0 matrix which introduced lattice strains into the interface of the AuCu I phase and the matrix. The hardness decrease in the later stage was caused by the formation and coarsening of the lamellar structure. Only 1 wt% of In resulted in the Zn-containing InPd phase formation, which induced an initiation of the grain boundary precipitation in the specimen alloy.

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In the hardness test, the hardness began to increase and reached a maximum value with increasing ageing time, and subsequently the hardness decreased gradually. By considering XRD results and SEM observations together, the solution-treated specimen consisted of three phases, the Ag-rich alpha 1 phase as a matrix, the Cu-Pd alpha 2 phase and the CuPd beta phase with a CsCl-type as particle-like structures. By ageing the specimen, the Ag-rich alpha 1 and Cu-Pd alpha 2 phases were transformed into the Ag-rich alpha 1' and Cu3Pd alpha 2' phases, respectively. The CuPd beta phase with a CsCl-type was not changed apparently during the ageing process. From the hardness test, XRD, SEM and EDS, it could be derived that the hardness increased by the diffusion and precipitation of the Cu-rich phase from the Ag-rich matrix during the early stage of phase transformation of alpha 1 into alpha 1' and that the progress of coarsening of the Cu-rich precipitates with an entanglement structure caused the hardness decrease during the later stage of phase transformation of alpha 1 into alpha 1'. The particle-like structures composed of the Cu-Pd alpha 2 and the CuPd beta phase with a CsCl-type did not contribute to the hardness change.

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To improve corrosion resistance of Ni-Ti orthodontic wires, anodic oxidation was done using direct-current power source in different concentration of NaOH or H₂SO₄ solutions. By SEM observation and XPS analysis, formation of smooth and thicker oxide films on surfaces of the wires was confirmed.

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歯科修復用材料として合金などの金属材料、硬質レジンなどの有機材料、陶材などの無機材料およびその複合材料が用いられている。一般的に、人は平均１年間に400,000回の咀嚼を行うといわれている。その度に上下歯牙や修復物の接触により摩擦摩耗現象が起こっていると考えられる。この摩擦摩耗の発生により歯牙や修復物が磨り減り、咬合高径を低くし、その結果、顎関節に異常を起こすことが予想される。このような観点から、修復物に使用される材料を種々組合せた時の摩擦摩耗挙動を検討することは材料の機械的性質や化学的安定性試験と同様に重要である。われわれはこのような観点からTypeIV金合金および12％金パラジウム銀合金、試作チタン合金およびステンレスSUS304の摩耗特性を検討した。

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Au-28.3 mass% Pt alloy was a MRI-artifact-free alloy and possibly a base alloy for biomedical application. The mechanical properties was probably not sufficient for the application but could be improved by working and age hardening. Au-Pt phase diagram suggested that the hardening was caused by phase separation.

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In order to obtain basic data for the establishment of a dental examination for metal allergy, saliva characterization and elution behavior of dental alloys to human saliva were examined. The present results did not show any direct relation between saliva and elution from dental alloys in terms of metal allergy. However, further detailed studies on saliva are still needed.

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The ZrO2 coating was more homogeneous and more complete at -0.5 V than at -0.8 V.

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The purpose of the present study was to evaluate the effect of combined addition of Ga and In on properties of 50Pd-25Au-15Cu-10Ag alloy. As Ga increased from 1% to 3% and In decreased from 3% to 1%, the proof stress of the alloy increased whereas its elongation and coefficient of thermal expansion decreased.

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Objective: Pure Ti as well as Ti-6Al-4V alloy exhibit excellent properties for dental implant applications. However, for a better biocompatibility it seems important to avoid in the composition the presence of V due to the toxic effects of V ion release. Thus Al and V free and composed of non-toxic element such as Nb, Zr alloys as biomaterials have been developed. Especially, Zr contains to same family in periodic table as Ti. Addition of Zr to Ti alloy have an excellent mechanical properties, good corrosion resistance, and biocompatibility. In this study, effects of Zr content on the electrochemical characteristics of Ti alloy for biomaterials have been investigated using by electrochemical methods. Methods: Ti-Zr(10, 20, 30 and 40 wt%) alloys were prepared by arc melting and homogenized for 24 hr at 1000 ?C in argon atmosphere. Phase constitutions and microstructure of the specimens were characterized by XRD and SEM. The corrosion properties of the specimens were examined through potentiodynamic test ( potential range of -1500 ~ 2000 mV in artificial saliva solution by potentiostat (EG&G Co, PARSTAT 2273. USA ). Results: In as-casted and homogenized Ti-xZr alloys, ?-phase was identified by XRD. Microstructures were changed from lamellar structure to needle-like structure as Zr content increased. From the results of polarization behavior in the Ti-xZr alloys, it was found that the corrosion resistance was increased with increasing Zr content. Conclusions: Consequently, in the Ti-xZr alloys, surface stability for biomaterials increased as Zr content increased.

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Ti-Hf (10, 20, 30 and 40 wt %) alloys manufactured by non consumable vacuum arc melting furnace. All the specimens were heat treatment at 1000 celsius temperatures for 24hr in Ar atmosphere followed by furnace cooling and quenching into 0 celsius temperatures ice water, respectively. Phase constitutions and microstructure of the samples were characterized by XRD, SEM and investigated mechanical properties using Micro Vickers hardness tester. The results were as follows: 1. Microstructure clearly observed that lamellar structure translated to needle-like structure with increased Hf contents. Especially, microstructure of water quenched Ti-Hf specimens more fine than furnace cooling specimen. 2. As a result of XRD, a -phase peak was detected for all samples. 3. From the results of Micro Vickers hardness test, Ti- 40Hf alloy showed significantly increasing of hardness and tensile strength than others in the case of both water quenched and furnace cooling sample.

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In biomedical implants and dental fields, titanium has been widely utilized for excellent corrosion resistance and biocompatibility. However, Ti and its alloys are nonbioactive after being implanted in bone. In this study, for the purpose of improvement in biocompatibility the anodic TiO2 layer on Ti-xNb alloys were fabricated by electrochemical method in phosphate solution, and the effect of Nb content on the pore size, the morphology and crystallinity of Ti oxide layer formed by the anodic oxidation method was investigated. The Ti containing Nb up to 3wt%, 20wt% and 40wt% were melted by using a vacuum furnace. The sample were cut, polished, and homogenized for 24hr at 1323K for surface roughness test and anodizing. Titanium anodic layer was formed on the specimen surface in an electrolytic solution of 1M phosphoric acid at constant current densities (30mA/cm2) by anodizing method. Microstructural morphology and surface roughness of oxide layer were observed by FE-SEM and roughness tester, respectively. The structure of alloy was changed from a-phase to b-phase with increase of Nb content. Surface roughness test and SEM results, pore size formed on surface and surface roughness decreased as Nb content increased.

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Electrochemical properties of MC3T3-E1 cell cultured Ti-Ta alloy with low elastic modulus were investigated for biomedical applications. In this study, electrochemical behaviors of surface modified and MC3T3-E1 cell cultured Ti-30Ta alloys have been investigated using various electrochemical methods. The Ti alloys containing Ta were melted by using a vacuum furnace and then homogenized for 6 hrs at 1273 K. MC3T3-E1 mouse osteoblasts for 2days. The microstructures were conducted by X-ray diffraction (XRD) meter and field emission scanning electron microscope (FE-SEM). The corrosion resistance was measured using Electrochemical impedance spectroscopy (Potentiostate, Model 263, EG&G, USA) and Potentiodynamic (-1500 mV ~ + 2000 mV) test in artificial saliva solution. From the microstructure analysis, Ti-Ta showed the martensite structure of a+b phase. The microstructure was changed from lamellar structure to needle-like structure as Ta content increased. Morphology of MC3T3-E1 cell cultured on the Ti-Ta alloy have a quite round form. From corrosion test of MC3T3-E1 cell cultured Ti-Ta alloy, corrosion resistance increased as Ta content increased. From the analysis AC impedance analysis in artificial saliva solution, Rp value of MC3T3-E1 cell cultured Ti-40 Ta alloys showed higher than those of other Ti alloy. Polarization resistance of cell-cultured Ti-Ta alloys increased in compared with non-cell cultured Ti alloy.

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The purpose of this study is to examine the color differences and weight change of Ag-Sn-Zn-In alloys after immersed in electrolyzed acidic, neutral and alkaline water. In order to examine change of water used for immersion, we measured pH value, residual chloride density and oxidation-reductive potential (ORP).

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生理食塩水中，精製水中，大気中において歯科用金銀パラジウム合金の疲労き裂進展特性について調べた．疲労き裂の進展にはき裂開閉口挙動が大きく影響をお及ぼすので同時にき裂開閉口挙動の観察も行った．生理食塩水中ではき裂閉口を助長するので疲労き裂進展抵抗が上昇することが分かった．そこでき裂閉口を助長させる化学成分についても検討を行った．ここで調査対象としたのは銅と銀の成分量についてである．その結果，銅の成分が多い方が破面上堆積物を増加させ，き裂閉口を助長させることが分かった．

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Introduction: The major cause of late failures could be attributed to peri-implant infections. Complete removal of bacterial deposits and their toxins from the implant surface is not necessarily achieved with conventional, mechanical therapy. Therefore, development of novel systems for peri-implantitis is required. As lasers can achieve excellent tissue ablation with strong bactericidal and detoxification effects, they are one of the most promising new technical methods for peri-implantitis treatment. The aim of this study was the morphological, the chemical and structural analysis of laser irradiated 3 different endoosseous dental implant.. Materials and Methods: Ninety titanium with three different surfaces (machined surface, MS; RBM treated surface, RS; anodized surface, AS) were used to evaluate surface changes. Titanium discs were equally and randomly assigned to the following test: diode laser irradiation or Er/Cr:YSGG laser irradiation at 5 different energy levels (1 W, 2 W, 3 W, 4 W and 5 W). The surface of each disc was irradiated on the middle of the disc for 10 seconds. The distance from the end of the delivery system was kept direct contact on the disc surface. The SEM observation was carried out for evaluating the surface morphological alterations such as signs of melting as well as micro-cracks. The EPMA examination was additionally performed to estimate the compositional alteration. The XRD analysis was done to estimate the structural alteration by laser irradiation. Results: Diode laser and Er/Cr:YSGG laser irradiation did not affect the compositional and crystalline structural alterations of titanium surface at any different power levels, but morphological changes were observed. Diode laser did not damage the implant surface at 1-3 W, but damages were observed above 4 W. All surfaces were damaged at 5 W. Er/Cr:YSGG laser could damage on RBM treated and anodized surface even at low energy level, but no damage was observed on machined surface at 1-2 W. Especially, anodized surface damaged from 1 W. Conclusions: Diode laser was safer than Er/Cr:YSGG laser if diode laser can control temperature elevation. However, further studies are required to examine microbiologic aspects and can control temperatures elevation that occurs during diode laser treatment.

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We have studied the deposition of calcium phosphate compound (CPC) on Ti by an anodization of it with alternate polarity inversion in a hydroxylapatite (HAP) supersaturated-H3PO4 solution prepared at pH 3 (sHAP3 solution). The characteristics of the CPC deposited on Ta, Nb and Zr (valve metals) by the same process of anodizing Ti were studied with FTIR, XRD, AFM and XPS. The results show that the CPC was a calcium deficient HAP with nano grain size. The XPS spectra of the specimen treated for the valve metals yielded that the anodic oxide films had phosphorus incorporated into them.

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The surface treatment by the use of sandblast media combined with steam cleansing on titanium to increase the bonding strength with porcelain was performed. Both sandblast treatment and steam cleaning on titanium showed significant increase of the bonding strength between titanium and porcelain.

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The results indicated that the expected excellent corrosion resistance and biocompatibility of the experimental Ti-20Zr and Ti-30Zr alloys, which were similar to those of pure Ti used as standard dental materials, suggesting their potentials for dental applications.

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The present study aims to investigate the effect of anodization time on pore features of oxide nanotubes obtained from neutral electrolytes. The oxides were heat-treated and soaked in simulated body fluid (SBF) for a specified time to produce HA. The effect of heat-treatment on the formation of HA is also studied.

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Titanium and its alloys are used for implant applications in orthopedics and dentistry because of their biocompatibility. However, when it is applied in body implant applications, it does not bond directly to the bone. In order to improve bone-bonding ability titanium surface modification methods are usually adopted. Electrochemical cathodic deposition is one such technique and can be used to deposit hydroxyapatite (HA) on the titanium implant material. Electrochemical deposition of HA coating can be conducted at room temperature. The coating morphology can be controlled by modifying the deposition parameters. Also these are expected to show good results in vivo. Purpose of this study is to know the influence of current density, bath temperature on the kinetics of hydroxyapatite coating formation on titanium substrate.

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Ti-Al-Nb合金をPd基金属ガラスで赤外線ろう接を行った.接合試料は37度のHunk's液中で長時間浸漬し，液中で曲げ試験を行った.

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Commercially pure titanium has been adopted by the dental profession as a metal for crown, bridge, and dental implant for more than a decade, because of their high toughness and excellent biocompatibility. Titanium dioxide (TiO2) has received great attention because of its high reactivity and chemical stability under UV light irradiation. Photocatalytic activities of surface modified TiO2 films were evaluated by methylene blue degradation test. Microorganisms used in anti-adherence test were Streptococcus mutans ATCC 31989 and Staphylococcus aureus ATCC 29231. The TiO2 film treated for 10min at 200Wshowed the highest degradation efficiency of MB. The concentration of MB reduced from 5.0 to 4.1 ppm in 4 hr under 30W fluorescence light. The number of S. aureus was 500 CFU in the case of the nitrogen and nitrogen gas plasma treatment when illuminated with visible light for 24 hr, whereas it was 25 x 106 CFU in the control. Plasma treatment is an excellent process for surface modification of photocatalytic TiO2 films. Surface modified TiO2 films can be used to prevent the growth of oral pathogen during orthodontic treatment.

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We have already found titanium plates treated with discharging in NaCl solution and titanium cast plates obtained from MgO-based investment with an additive of NaCl powders into the powder of investment showed antibacterial effects. Especially possibility of anti-bacterial effect of cast titanium seems promising to be applied in clinics. Considering the manipulation of investment, in this study we investigated the effect using the NaCl solutions for mixing liquid of investment.

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This study presents the first observation of the interface between acid-etched titanium and cultured osteoblastic tissue at micro- and ultra-structural levels. EDS line scan revealed that elemental peaks of Ca and P existed in an identical level of vicinity.

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　本研究は、デンタルインプラントフィクスチャー形状が周囲骨に与える影響について ３次元有限要素法を用いて比較検討を行った． ３次元有限要素モデルは、下顎第一大臼歯にインプラントを埋入したものとし、周囲骨として、 皮質骨と海綿骨を想定して作製した。 荷重条件として、垂直荷重５００N、拘束条件として、皮質骨底部を完全拘束し、 解析を行った。結論として、インプラントフィクスチャー部の長軸が長いものほど応力分布の軽減が認められた。 形状により、周囲骨の応力分布に差異が認められた。

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Commercial pure titanium and titanium based alloys are widely used as a dental root implant material in clinical dentistry and as an orthopedic implant material. Surface modifications are widely used to adjust the properties of the titanium surface to the specific needs of the particular medical applications, but there are certain disadvantages such as poor osteoconductive properties and low corrosive-ware resistance. Hydroxyapatite(HA, Ca10(PO4)6(OH)2) has been widely used as a coating materials for dental and orthopedic implants for many years, due to close similarity of chemical composition and high biocompatibility with natural bone tissue. However, interfacial bond strength of the HA coating on the untreated Ti substrate is observed to be low. Anodization was performed by potentiostatic experiment using a conventional two electrode configuration in 1 M H3PO4 electrolyte at room temperature. The HA coatings was produced by reactive RF magnetron sputtering on anodized Titanium oxide layer, using target of HA (99.99%). A RF power of 100 W was applied to the target during 40 min for all the depositions, obtaining an average with a constant substate temperature of 100 C. A set of coating was obtained with a constant argon gas flow of 40 sccm. The HA thin films were found to achieve total crystallinity. From the electrochemical test, corrosion resistance decreases in the case of HA film coating. Therefore HA coated surface shows the good corrosion resistance.

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口腔内における放射線治療後に,歯の切削が容易になるという報告が臨床家より報告されている．しかしながら，60kGの放射線照射直後においては，象牙質の引張強さおよび被削性への影響は認められなかった．そこで，本研究では放射線照射した象牙質をクロラミンT,チモールの2種類の消毒液中に1年保管した後の引張強さの変化を測定したので報告する．

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Fukase et al. developed the bio-artificial material for the bone filling cement (alpha-DTC). Alpha-DTC has enough mechanical properties for supporting occlusal force with bone. When alpha-DTC was applied for bone defect area, new bone formed at the space between the original bone and alpha-DTC. The volume of new bone formation is limited by the volume of this space. In this study, the disintegration of alpha-DTC was improved and evaluated. The disintegration ratio of alpha-DTC with HPC and PLG increased chronologically on calvaria bone cavities of rabbits. The disintegration of artificial biomaterials is necessary for increasing the space of bone formation. In order to set the functional characteristics into the alpha-DTC, choosing appropriate binders/fillers are important.

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ヒトテロメレース触媒サブユニット（hTERT）およびヒトパピローマウイルス(HPV)のE6, E7遺伝子をイヌ歯髄細胞へ遺伝子導入を行い、不死化細胞の分離および新規覆髄剤の象牙質再生効果をin vitro培養実験でモニタリングできる実験システムの構築を研究の目的とした。

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Eembryonic stem cell test (EST) is an in vitro assay that has been developed to assess the teratogenic and embryotoxic potential of drugs and chemicals. We examined the effects of dental alloys containing indium using EST and the rat whole-embryo culture method. These Results differed from the report of the animal experiment about the indium compound, and demonstrate that there is a very low embryotoxicity risk from the alloys containing indium examined in this test.

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本研究では，デキストリン-HAP複合体を作製して，in vivoにおける生体適合性の評価と骨欠損部に移植時の有効性を検討した．9週間後では炎症性細胞の浸潤は認められず線維性結合組織による被包化が観察され，緊密に骨補填がされていた．デキストリン-HAP複合体は，有効な骨補填材であることが示唆された．

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This study evaluated safety and reliability of dental magnetic attachments on the basis of bone compatibility of the magnetic stainless steels (XM27 and 447J1) and activities of osteoblasts (SaOS-2) under a static magnetic field given by the magnetic assembly composing the dental magnetic attachments.

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Introduction: Recent reports suggest that osteoblast in bone marrow plays important roles for quiescence of hematopoietic stem cell (HSC) 1,2). Osteobast attach to the trabecular bone, and the Ca concentrations are altered by the degree of the bone maturation in this small microenvironment (HSC niche). To understand the effect of Ca ions on HSC niche related osteoblast functions, we cultured osteoblast with different concentration of Ca ions, and investigated the HSC niche related gene expression in osteoblast. Materials and Methods: Osteoblast-like cell (3T3E1) was used in this study. Cells are cultured in?MEM containing 10% FBS and P/S. CaCl2 (1.8-50 mmol/l) was added in cell culture medium to investigate the effect of Ca ions on osteoblast functions. Cell proliferation was measured by WSD assay, and the real time RT-PCR was carried out to measure the HSC niche related gene expression in osteoblast. We also investigated the alterations of osteogenic gene expression under the different concentrations of Ca ions. Von Kossa staining was carried out to understand the effect of different Ca concentrations on in vitro mineralization. Results and Discussion: Cell proliferation results showed that 6-14 mmol/l of Ca containing medium enhanced cell proliferation rate, however, cells in each conditions reached to the confluent after 7 days of culture. Confluent conditions were maintained at the further culturing period in 1.8-14 mmol/l of Ca containing medium, however, cell aggregations were observed onto cell layer in 30-50 mmol/l of Ca containing medium. To understand the HSC niche related gene expression of osteoblast caused by Ca ions, we examined the gene expression level of angiopoietin-1/-2. The results showed that 14 mmol/l of Ca containing medium enhanced approx. 3.6 folds of angiopoietin-1 expression compared with control (1.8 mmol/l of Ca) or 50 mmol/l of Ca containing culture at day 11. In contrast, angiopoietin-2 expression was minimum at day 11 and showed highest value at day 7. Von Kossa staining showed that mineralization was highest at 6mmol/l Ca containing culture, and this result was supported by previous report 3). Thus, our data suggested that Ca ions highly affect on HSC niche related gene expression in osteoblast, and these alterations might be caused by cell conditions including cell attachment to matrix and cell-cell interactions. References: 1) Wilson A, Trumpp A. Bone-marrow haematopoietic-stem-cell niches. Nat Rev Immunol. 2006,6,93-106. 2) Arai F et al. Tie2/angiopoietin-1 signaling regulates hematopoietic stem cell quiescence in the bone marrow niche. Cell. 2004,118,149-61. 3) Maeno S et al. The effect of calcium ion concentration on osteoblast viability, proliferation and differentiation in monolayer and 3D culture. Biomaterials. 2005,26,4847-4855.

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We made mixed self-assembled monolayers (mixed SAMs) with various ratios of amino, hydroxyl, carboxyl, and methyl groups and report the relationship between the surface composition and water contact angle, as the surface composition change induces cell growth and differentiation of the growth pattern of each cell under the same surface conditions The effect of the surface functional groups on cell proliferation was examined, and it was able to be shown that the waveform-like pattern of cell proliferation for the surface composition change differed for each cell.

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The present study investigated the differentiation of ATDC5 on porous titanium. The mRNA expressions of type II, X collagen, aggrecan and N-cadherin were investigated using real-time PCR. This study indicate that ATDC5 cells differentiated into chondrocytes on the porous titanium.

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In this study, we examine to isolate oral bacteria with a capacity to form biofilm on acrylic resin dentures using a scanning electron microscopy. The results indicate that several denture plaque bacteria exhibit biofilm phenotype.

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We tested to exploit a simple method for isolating biofilm-forming bacteria from denture plaque on acrylic resin dentures. The results might suggest that the combination of turbidity on their culture medium and positive calcofluor reaction can be used as a simple isolation method.

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ジルコニアは、歯科修復材料およびインプラントに用いられている。しかし、ジルコニアへの接触が細胞機能にどのような影響を与えるかは不明であった。我々が最近開発した方法により、この点につき種々の細胞を用いて検討した。ヒト歯肉線維芽細胞HGFが銅板に接触した場合、細胞付着能を失い、シスチン(CYS)の消費の増大、グルタミン(GLN)の利用の低下を伴う急激な細胞死が誘導された。これに対して、ジルコニア(A1, B3, C4, D2)との接触では、細胞付着能が維持され、CYSの消費やGLNの利用に影響を与えなかった。短期間の接触では、ジルコニアは、細胞傷害活性を有しないことが判明し、口腔領域への応用が支持された。

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我々は、これまで銅板との接触によりHL-60細胞において急激な細胞が誘導されることを報告した。今回、この発見の一般性を確かめるために、我々が最近開発した方法を用いて、種々の金属との接触が細胞の機能に与える影響につき検討した。銅板との接触は急激な細胞傷害活性を誘導したが、金との接触では細胞の増殖がむしろ増強した。他方、銀あるいはパラジウムとの接触では時々細胞傷害活性が誘導されたが、その場合グルタミンを含むほとんどのアミノ酸の消費がなくなり、抑制性アミノ酸のグリシンやグルタミン酸の産生が促進した。アミノ酸の代謝は、金属との接触により誘発される細胞機能の変化を測定するのに有効であることが示唆された。金属表面の性状は、金属に対する細胞の反応を変化させる一つの要因と思われる。

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In view of the beneficial effects of both fluorine(F) and silver(Ag) ion deposition by Plasma-based ion deposition(PBID), the aims of this study were to evaluate the depth profile of deposited dual elements and spectra of binding conditions by X-ray photoelectron spectroscopy (XPS), as well as evaluate the effect of dual ion implantation or deposition on contact angle. XPS analysis suggested that Ag was bound with Cr, and F was bound with Cr and carbon on the surface of SUS. Fluorine and silver ion deposited SUS surface showed a significantly higher contact angle than non-deposited or dual ion implanted surface. The mentioned above, it was suggested that F and Ag deposition is available to the surface modification for prevention oral infection disease.

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This study aimed to establish in vitro model to simulate biofilm formed in dental unit waterlines (DUWLs), and to investigate the ability of fluoride-coating tube to inhibit biofilm formation. Incubation of the waterline tube for 4 days and over in the mixed flora of three predominant bacteria, which were isolated from biofilm clinically formed, was found to be an adequate method to simulate formation of matured biofilm in DUWLs. Using this model, a polyvinylidene fluoride (PVDF)-coating tube was proven to be effective in preventing biofilm formation.

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歯質表面への初期付着では、口腔細菌はイオン結合、疎水性相互作用などを介して付着する。その中には、糖鎖-レクチンによる選択的な相互作用も知られている。そこで本研究では、Streptococcus mutansと人工複合糖質高分子の相互作用について検討した。その結果、菌溶液に人工複合糖質高分子を添加したところ、糖鎖構造による選択的な増殖阻害および時間依存的な阻害が観察された。また、添加初期では菌体表面への人工複合糖質高分子の付着が観察された。これらの結果より、阻害機構は選択的な糖鎖認識を含むものと推測される。

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To investigate in vivo tissue reaction and evaluate biocompatibility, high resolution observation of CNTs in tissue was carried out by high voltage electron microscopy (HVEM). The study showed that CNTs are not strong prophlogistic substances and they have rather excellent biocompatibility for cell growth, which would serve for biomedical applications.

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著者らはこれまで、金属材料の生体内での溶出挙動を蛍光XAFS法（X-ray absorption fine structure）を用いて測定してきた。本研究では耐食性が高いとされるTi, Ni-Ti及びSUS304を動物皮下に埋入した周囲組織中に溶出したTiとNiの状態を蛍光XAFS法で分析し、周囲組織への溶出を確認した。

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