新規の低粘性のエトキシ化ビスフェノールAジメタクリレートをベースモノマーとしたコンポジットレジンを試作し、物性を調べた結果、これらのモノマーはフロアブルコンポジットレジンのモノマー混合物として有効であることが明らかとなった。

抄録全体を表示

Introduction: New Light-cure fluoride releasing esthetic tooth make-up material has been induced. The purpose of this study was to characterize color of new resin composites.. Materials and Methods: Composite resin (SI-R20209 Shofu) disks with diameters approximately 8mm were made by injecting materials onto a silicone coated glass slide and flattened to 0,5 mm with another silicone coated glass slide and light cured for 40 seconds. The resin disks( White Group (BW1,BW2,BW3,BW4,WO),Color Group (Reddish,Yellowish,Natural,Natural-O)) was measured in CIE L*a*b* coordinates using a spectrophotometer (PR-650, Photo Research) over white and black backgrounds(5 samples for each resins). Contrast ratio(CR) were then compared. Results: The color of composite resin on white background were as follows; Color L*(SD) a*(SD) b*(SD) BW1 97.8 (0.4) -1.8 (0.1) 4.4 (0.5) BW2 98.2 (0.3) -2.6 (0.1) 6.4 (0.4) BW3 97.7 (0.5) -3.2 (0.1) 6.7 (0.2) BW4 97.9 (0.3) -3.7 (0.1) 7.2 (0.2) WO 98.0 (0.4) -4.2 (0.1) 11.9 (0.7) Natural 89.0 (0.3) 3.1 (0.2) 28.2 (0.4) Natural-O 86.1 (0.8) 4.8 (0.2) 23.5 (0.8) Reddish 89.0 (0.2) 7.5 (0.3) 17.2 (0.2) Yellowish 93.7 (0.2) -2.5(0.1) 29.7(0.5) The results showed L*values of CIELAB color composite color values were significantly different between 2 groups(White Group and Color Group). Conclusions: New Light-cure fluoride releasing esthetic tooth make-up material were showed higher L* values on white background.

抄録全体を表示

To make a base polymer of a new soft resin material, the copolymer of 1,3-bis (methacryloxypropyl) tetramethyl disiloxane(BMPMS) and methyl methacrylate monomer(MMA) was used. The copolymer of BMPMS and MMA showed high elasticity.

抄録全体を表示

The purpose of this study was to examine the effects of curing sequence and polymerization temperature on the mechanical properties of provisional restoration resins.

抄録全体を表示

Mixtures of two urethane oligomers and urethane oligomers with the methacrylate monomers were made, and the viscosity of the mixtures and mechanical properties of the polymers were measured to apply the soft type urethane oligomer for the soft lining material.

抄録全体を表示

We recently developed a prototype ethanol-free tissue conditioner by using a combination of vinyl esters (VE) and PEMA to overcome the disadvantages of conventional ethanol-containing tissue conditioners. However, there is little information on the general toxicity of VE. Gene expression changes provide specific mechanistic information concerning the mode of action of toxicants. The purpose of the present study was to monitor the drug toxicity of VE at the transcriptional level.

抄録全体を表示

The aim of this study was to evaluate the effects of experimental fiberglass strengthener on the flexural properties of resin denture base comparing to a conventional metal strengthener.

抄録全体を表示

The mechanical properties of thermo-polymerized VE/PEMA pastes were evaluated for seeking the possibility as long-term denture liners. It was possible to make the thermo-polymerized VE/PEMA pastes either soft or hard character by selecting the chemical structure of VE in VE/PEMA pastes. Therefore, the thermo-polymerized VE/PEMA pastes showed the potential as long-term soft and/or hard denture liners.

抄録全体を表示

Polymethylmethacrylate (PMMA) has been commonly used as a main ingredient of denture base resin because of its high transparency. However application in clinical use has been limited because of its inherent brittleness. It induced the low resistance to impact against extraoral force such as accidental falling. In this study, core-shell composite particles composed of a rubbery core and a glassy shell (PMMA) were prepared to improving impact strength for denture base resin. Denture base resin toughened by core-shell composite particles, impact strength was larger than common denture base resin. Impact strength was increased with increasing content of core-shell composite particles.

抄録全体を表示

Soft denture lining materials are required to be minimally contaminated from the viewpoint of oral hygiene. The experimental materials containing fluorinated monomers showed high flexibility and high contamination resistance. It is suggested that these materials will be clinically applicable as soft denture lining materials in the future.

抄録全体を表示

The purposes of our study are that the development and evaluation of the new material "TissueCare" which consists of polymeric plasticizer instead of an ordinary one. From the comparison with other Tissue Conditioners, "TissueCare" maintains the softness, and there is only slight elution of plasticizer in "TissueCare".

抄録全体を表示

Polu(methyl methacrylate) plates were used to study the effect of the defects in the flexure strength test. If any kind of defect exists, the crack was straight. In the fracture surface, inicial point was clearly shown. In the tensile side (the lower side) the ripple-like patterns were shown. The comprssion side (upper side) was tansparent and smooth.

抄録全体を表示

In the heat-cured resins, the polymer particles which did not react with monomer are visible. In the flexure strength test, these particles were extremly distorted in the tensile side (the lower side of the specimen). In the fracture surface, the same patterns reported in Part1 (poly(methyl methacrylate) plate) were observed.

抄録全体を表示

The rheological property of the material with low viscosity, such as tissue conditioner, is markedly affected by the amount of water absorbed. This investigation was to examine the relationship between creep compliance or fluidity and the amount of absorbed water, and to discuss the effect of absorbed water (moisture) on the rheological properties of tissue conditioners.

抄録全体を表示

緑茶ポリフェノールのEGCGでコラーゲンを架橋した。この架橋コラーゲンの生体内組織適合性と分解性を検討した。

抄録全体を表示

The purpose of this study was to evaluate the effect of blockage the flowability of a polyether impression material in the Shark Fin Test. The flowability of a polyether impression material was significantly influence both by the number and diameter of the blockage.

抄録全体を表示

In the present study, the effects of substrate temperatuere and solution pH on the HA film formation were eexamined and the mechanism of HA deposition was elucidated. It was demonstrated that the growth of HA layers was not controlled by the diffusion process of calcium and phosphate ions in the solution. It was also found that the deposited HA gradually dissolved in a saline solution and the pH of the solution increased due to the released hydroxyl ions and phosphate ions. Both releasing calcium ions and the buffering action of the HA film probably play an important role in enhancing bone formation around the implant.

抄録全体を表示

　本研究では、CAD/CAM用の部分安定化ジルコニアおよびポーセレンブロックに対する2種の接着性レジンセメントの接着強さについて、表面処理の及ぼす影響とともに比較検討した。
　以下にその結果を示す。
　ジルコニアおよびポーセレンに対するレジンセメントの接着強さはサンドブラストおよびプライマー処理を行った条件がもっとも大きな値を示した。ポーセレンに比較してジルコニアの接着強さは有意に小さな値を示した。

抄録全体を表示

Marginal fracture is a shortcoming of ceramic restoratives due to brittle nature of the ceramic material. The influence of marginal angle on the marginal fracture was evaluated using indentation fracture technique in bonded dental ceramics.

抄録全体を表示

Recently, high strength ceramics such as zirconia and alumina are widely used in dental restoratives. Furthermore, these ceramics may be applied to implant fixtures. However, there are few information about the X-ray opacity of these ceramics. The aim of this study is to investigate the X-ray opacity of zirconia and alumina in comparison to commercially pure titanium (cpTi).

抄録全体を表示

炭酸含有アパタイト焼結体の高温下での超塑性挙動と、それによる物性の変化を検討した。800℃で荷重10MPaの条件では約70%の塑性変形を示した。この変形体の物性について検討した結果、Ｘ線回折およびSEM観察では結晶の配向が認められ、空隙の減少も認められた。硬さについては荷重方向に平行な面で硬さが増加した。また、加熱変形後も変形体には約９wt%の炭酸が残留し、炭酸含有アパタイトとしての応用の可能性が示された。

抄録全体を表示

We have previously synthesized strontium-substituted hydroxyapatite (Sr-HAP) by using Sr containing solution, but more solubility is required. Therefore, the purpose of this study is to develop Sr-substituted carbonate apatite (Sr-CAP) by mixing alpha-tricalcium phosphate containing up to 20 mass % SrCO3 with Sr-containing solutions.

抄録全体を表示

Introduction:
Ideal bone graft material is a material which will be replaced by new bone. Biodegradable substitutes corresponded with the ideal concept have received increasing interest.
We developed a new biodegradable bone graft material based on calcium phosphate. In this study, we performed chemical analyses of the new bone graft material and evaluated the effects of this material on the cytotoxicity in the mouse bone stromal cell as well as the regeneration of calvarial bone in Sprague-Dawley(SD) rats.
Materials and Methods:
Calcium phosphate glass(CPG) powder in the system CaO-CaF2-P2O5-MgO-ZnO was prepared. The 7.5 wt% Na₂CO₃ was added to 92.5 wt% CPG. This powder was mixed with 1.5 M NaOH solution at the ratio of 4 g/mL. The mixed paste was loaded into a mould. The hardened specimens were stored at 37^oC under 100% relative humidity. After 24 hrs, some specimens were used for the chemical analyses and the preparation of extracts and the others were grounded to granules of 500-600 um and freeze-dried for the animal test. The chemical analyses were carried out using XRD, EPMA and DTA. The cytotoxicity was determined by MTT method using ST2 cell (mouse bone marrow stromal cell). Brushite was selected as the control group of cytotoxicity test. The extracts were obtained from 24 hrs immersing in PBS at 37^oC and exposed to the cell for 24 hrs. A circular defect with 8 mm diameter was created on calvarial bone of SD rat. The control group was not grafted with any material and the experimental group was placed with the new graft material. After 2 and 8 weeks, animals were sacrificed. The tissue slides for histomorphometric analysis were prepared using H-E staining method and examined using a light microscope.
Results and Discussion:
In the XRD data of the bone graft material, no crystalline phases were detected. This amorphous phase is the calcium phosphate which has a Ca/P molar ratio of 0.6 and 15 at% Na in the result of EPMA. Moreover, this material has showed the different pattern from the CPG in the DTA data. The relative cell viability of the experimental group was higher than that of the control group. In addition, the enhanced effect on the proliferation was observed in the experimental group. In animal test, the immature bone was already formed around the graft material after 2 weeks in the experimental group, while the defect was filled with loose connective tissue after 8 weeks in the control group.
Conclusions:
A novel developed bone graft material is expected having a fast resorption rate due to their amorphous phase and low Ca/P ratio. This material showed superior cell viability than that of the commercial brushite product in spite of the fast dissolution. In addition, this novel material promoted a new bone formation in the calvarial defect of SD rat.
Acknowledgement:
This work was supported by grant No. R13-2003-12 from the Medical Science and Engineering Research Program of the Korea Science & Engineering Foundation.

抄録全体を表示

In this study, the glass powders of MgO-CaO-Al₂O₃-SiO₂-P₂O₅ system were fabricated to porous specimens using stearic acid as pore agent. The porosities of these fabricated porous glass-ceramics specimens were from 26.96% to 45.89% after sintering. The elastic modulus and bending strength were 2.26 to 4.35 GPa and 13.01 to 22.67 MPa, respectively. The pore size in the present study also seems to be in agreement with the cell penetration.

抄録全体を表示

Bi-layers porous glass-ceramic scaffolds using the replication and twice sinter methods were fabricated successfully in this study. Using this twice sinter method, not only would the higher mechanical properties be obtained by inner layer but the better biocompatibility also attained by outer layer.

抄録全体を表示

Low-crystalline carbonate apatite (CAP) foam that has quite similarities to cancellous bone in composition and morphology is expected to be an ideal bone replacement because it would show excellent osteoconductivity and cell-mediated resorbability in bone defect. However, preparation of the CAP foam cannot be done by traditional ceramic foam preparation since this method employs a sintering process at high temperature and this would make CAP decompose easily during the sintering process. Therefore, we attempted to prepare low-crystalline CAP foam by phase transformation based on dissolution-precipitation process. We prepared alpha-tricalcium phosphate (alpha-TCP) foam, that is stable at high temperature, by sintering, and investigated the feasibility to prepare low-crystalline CAP foam from alpha-TCP by hydrothermal treatment with sodium carbonate.

抄録全体を表示

The aims of this study were to establish an effective new silica coating method on the enamel surface using hydrogen peroxide (H2O2) solution and CO2 laser and to estimate the details of PHPS- silica conversion mechanism. Effective PHPS-silica conversion was conducted by CO2 laser-assisted rapid process regardless the different processing. It was concluded that silica coating method by a laser-assisted rapid process is expected to be applicable for safe, simple, and expeditious tooth coating.

抄録全体を表示

Introduction: Glass ionomer cements (GICs) have been popularly used for the restoration of tooth structures in dentistry. Along with their general use as a luting agent and direct filling restorative material, GICs are now gaining much interest for the repair and regeneration of hard tissues. To be potentially applicable in the regenerative areas, the GICs require improved mechanical properties and high osteogenic potential to regulate bone cell functions. For this purpose, herein we prepared bone-bioactive GIC by incorporating bioactive glass powders into the commercially-available ionomer cement and investigated the physical and mechanical properties as well as the in vitro bioactivity of the cements. Materials and Methods: Bioactive glass powder was prepared according to the sol-gel procedure reported in our previous paper. The glass powder was mixed with commercially-available ionomer cement GC Fuji I at 10 and 30 wt%. The setting time of the cements was measured using Vicat needle. The mechanical properties of the cements including diametral tensile strength (DTS) and hardness were measured after immersion in distilled water at 37 oC for different periods. For the in vitro bioactivity test, the hardened cements were immersed in a simulated-body-fluid and the surface change was observed with scanning electron microscopy (SEM, Hitachi). The weight change during the immersion test was also monitored. The tissue cell viability to the cements was examined by means of MTS assay. Results & Discussion: The measured setting time of the cements was in the range of ~2 to 7 min depending on the powder to liquid ratio and the composition. In particular, the addition of bioactive glass powder retarded the setting reaction of the ionomer cement. The mechanical properties (DTS and hardness) of the bioactive glass-added cements were in the similar levels with respect to those of the pure GC. Moreover, both mechanical properties showed only slight changes during the immersion in water at least for up to 10 days. However, the bioactive glass-added cements were shown to induce apatite-like mineral phase on their surface during the immersion in SBF, which was not the case in the pure GC. The tissue cells were observed to adhere and grow actively on the bioactive cements, with the cell viability to a significantly higher level than that on the pure GC. Conclusions: Current study showed the addition of bioactive glass into ionomer cement GC Fuji I did not degrade the mechanical properties such as hardness and DTS. Moreover, those mechanical properties were maintained during the immersion in distilled water at 37 oC at least for 10 days. Importantly, the in vitro bioactivity of the cements in SBF as well as the cell viability was significantly improved by the addition of the bioactive glass.

抄録全体を表示

歯科用CAD/CAMシステムで用いるためのハイブリッドセラミックブロックに対する3種類の接着性レジンセメントの接着力について　微少引っ張り試験を行った。その結果、いずれのレジンセメントも効果的な接着力を有することが判った。

抄録全体を表示

ヒドロキシアパタイト(HA)セラミックスのポーラスおよび緻密体の分極処理法と、処理されたHAの骨形成能の向上について報告する。現象的には疑似体液中での骨類似アパタイトの析出を中心に紹介する。

抄録全体を表示

The clinical success of ceramic restorations is heavily dependent on the cementation procedure. The purpose of this study was to evaluate the shear bond strengths of four resin bonding systems including ceramic primer and dual-cured resin luting agent to Procera AllCeram Zirconia (Nobel Biocare) intaglio surface.

抄録全体を表示

Introduction: This research paper focuses on whether the light curing pulp capping materials had actual improvements, preserving the advantages of Ca(OH)2. We thus observed the emission of Ca+ and P element and maintenance of high pH level, which are the advantageous properties of Ca(OH)2, measured the solubility to find out whether the problems were solved, and experimented microleakage, one of the most significant properties as a restoration material. Materials and Methods: Four pulp capping materials (Dycal, Ionosit, Lime-lite, Ultrablend plus) used in the study. The main component of Ionosit (DMG, Germany) is glass ionomer. Ion releasing (Ca and P ions) was measured with ICP-OES (Optima 4300 DV, Perkin-Elmer, USA) to detect the ion emission. Solubility test was performed with vacuum oven and electrical balance. Ion releasing and solubility test was conducted every week for the first five weeks and then after 30 days. The pH was measured in two groups. In the first group (C-group), deionized water was changed for fixed intervals, and in the second group (NC-group), deionized water was not changed from the beginning to end of measurement. Every specimen was measured its pH level on fixed intervals of 15 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 12 hours, 24 hours, 48hours, 3 days, 4 days, 5 days, 6 days, 7 days, 14 days and 21 days. Microleakage test also performed. Results: The experimental groups of light curing pulp capping materials have less Ca2+ emission compared to Ca(OH)2 paste. (Lime-lite, Ionosit: 1% of Dycal, Ultrablend: 20% of Dycal). Ultrablend had the most amount of emission among the light curing pulp capping materials (50 times more than other materials). Phosphorous ion was emitted in small amount from Ultrablend and Lime-lite and not emitted at all from Ionosit and Dycal. Ultrablend had the most amount of emission. Ca(OH)2 paste had substantially high rate of pH (11-12) and maintained it constantly. Ultrablend turned out to have the highest level of pH (8-9) among the light curing pulp capping materials. Solubility of the light curing pulp capping materials was very low. Ultrablend had solubility of 2-3 % and Lime-lite and Ionosit rarely had any degree of solubility. Microleakage in the inferior surface of composite resin appeared frequently in all the light curing pulp capping materials. The process of acid etching did not affect the result of microleakage. The inferior surface of composite resin had rather better results without acid etching. Conclusions: Ultrablend is expected to perform excellently as a pulp capping materials if only the problem of microleakage observed in the inferior surface of composite resin is solved.

抄録全体を表示

The purpose of this study was to examine how much the color of indirect resin composites placed on different colored abutments was affected when experimental resin cements with different transparencies were applied between the composite and the abutment. The transparency levels of the cement layer beneath the indirect composite resin influenced the color of the indirect composite more with the darker-colored abutment.

抄録全体を表示

This study aimed to evaluate the mechanical strength and the chemical composition of hydroxyapatite glass ionomer cement (HA-GIC).HA-GIC was significantly higher than conventional GIC at the flexural strength and resin modified GIC at the compressive strength. XPS showed the elemental spectra of Ca and P in the HA-GIC and HA100-GIC. The ratio of Ca/P in HA-GIC hydrogel matrix was different from pure hydroxyapatite. It suggests that the chemical reaction was occurred between hydroxyapatite and GIC.

抄録全体を表示

Bond strength of resin cements to zirconia were evaluated. The specimens pre-treated with silane coupling agent which contains 10-Methacryloyloxydecyl dihydrogen phosphate (MDP) and bonded with non-MDP-containing resin cement showed significantly highest shear bond strength.

抄録全体を表示

The purpose of this study was to evaluate and to compare the physical properties and chemical composition of MTA with those of commercially available pulp- capping agents.Our results demonstrate that the physical properties of MTA are as good as those of the 2 commercial dental pulp-capping agents used for comparison.

抄録全体を表示

クエン酸ならびにタンニン酸処理した象牙質へのレジン添加型グラスアイオノマーセメントの接着強さを測定した．接着強さはクエン酸処理により増加したが，タンニン酸処理のみでは増加しなかった．クエン酸処理に引き続いてタンニン酸処理することは接着強さを減少させることはなかった．

抄録全体を表示

ジルコニアセラミックスに対するレジンセメントとレジン添加型グラスアイオノマーセメントの剪断接着強さを計測した。プライマー処理を施したジルコニアセラミックスに対する剪断接着強さは未処理のものよりも高い値を示したが、これらは機能性モノマーを含んだレジン添加型グラスアイオノマーセメントよりも低い値となった。

抄録全体を表示

The purpose of this study was to determine the composition on the surface of MTA after it had been soaked in simulated body fluid (SBF).The deposits on MTA soaked in SBF were small and round crystals that mainly included calcium and phosphorus. Those crystals might be calcium phosphate-like deposits.

抄録全体を表示

Recentry, rapid-heat phosphate-bonded investments have been introduced. These rapid-heat investment save laboratry time and simplify the casting procedure. But, little information is available on the properties of these materials. This study examined the effect of heating condition on total expansion of phosphate-bonded investment.

抄録全体を表示

In our previous study, the feasibility of titanium casting using a room temperature mold with boron nitride (hBN) was investigated. In the present study, the temperature of the mold with hBN was 600 ºC. The improvement in the defects of titanium casting and the surface oxidization were investigated. The casting mold using hBN showed that the oxidization of the casting surface was made less at 600 ºC as well as at room temperature. The casting rate in 600 ºC mold was improved drastically in comparison with that of room temperature mold.

抄録全体を表示

To consider a cause to retard hardening of beta calcium sulfate hemihydrate(CSH), Zeta-potential values of CHPD and CHP crystal were calculated by the measurement of the electrophoresis of the crystal, respectively.

抄録全体を表示

Introduction: The increased use of all-ceramic restorations has resulted in a decline of metal-ceramic restorations, which fail to meet the aesthetic demand of patients. Zirconia-based ceramics are gaining popularity in dentistry, particularly in fixed prosthodontics, due to their superior biocompatibility, mechanical properties and the development of new technologies (CAD/CAM) which allow the fabrication of all-ceramic crowns and fixed partial dentures. Adjustments by grinding may be required to improve the fitting of the restoration, and sandblasting of the inner surface of the restoration is commonly used to enhance the adhesion of the luting agent to the framework. The fabrication of an all-ceramic restoration is therefore, conducted through a number of steps involving grinding, polishing, sandblasting and heat treatment. The influence of such steps on the flexural strength of Y-TZP is not fully understood. The aim of this study was to investigate the influence of grinding methods on the flexural strength and reliability of four commercially available zirconia dental core ceramics. Materials and Methods: Four commercially available dental zirconia ceramics (Cercon Base, Lava, ZirAce, and Digident Zir-Ceram HIP) were tested. The specimens (40 disks) were equally divided into four groups according to surface treatment (mirror polished, ground with 80, 140, and 800 grit diamond wheels). After surface treatment, surface roughness of specimens was measured using a confocal laser microscope (Conrad MRC-1024, Biorad, USA). Biaxial flexure test was used to calculate the flexural strength. X-ray diffraction analysis (XRD; D8 Advance, Bruker AXS, Germany) was used to estimate the relative amount of monoclinic phase. The reliability of strength was assessed through the Weibull distribution. Results were statistically analyzed by the ANOVA and Tukey multiple comparisons test (p=0.05). Results: Surface grinding has a significant influence on the surface roughness of zirconia ceramics, but surface roughness did not have linear relationship with grinding medium (80, 140 and 800 grit). DZC showed the significantly higher flexural strength than any other experimental groups. Flexural strength was significantly increased with surface grinding (p<0.05). Except ZRA group, the highest Weibull characteristic strength (?0) was observed at specimens ground with 140 grit diamond wheel. In ZRA group, specimen ground with 80 grit diamond wheel showed the highest Weibull characteristic strength, but there was no significantly difference between specimens ground with 140 or 800 grit diamond wheel (p>0.05). Except DZC group, the highest Weibull modulus (m) was observed at specimens ground with 140 grit diamond wheel. DZC showed the highest Weibull modulus at specimen ground with 80 grit diamond wheel. Zirconia ceramic contained 5.88-8.99% monoclinic phase after finer polishing (control group). The greatest amount of monoclinic phase (19.45%) is measured in DZC after grinding with 800 grit diamond wheel. The amount of monoclinic phase is significantly increased with surface grinding (p<0.05). The coarse grinding (80 grit) transformed less monoclinic phase than the fine grinding (140, 800 grit).

抄録全体を表示

熱膨張係数の異なる２種の長石質ガラス粒子を用いた歯科用ポーセレンの強化が報告されてきた．ガラス間の熱膨張係数のミスマッチが機械的性質の改善の理由として考えうる．シリカはガラスの主成分であり，４つの多形がある．溶融石英ガラスの熱膨張係数は小さく，クリストバライトの熱膨張係数は変態のために大きい．この研究の目的は，SiO₂の多形の添加が長石質ポーセレンの機械的性質に及ぼす影響を調べることである．

抄録全体を表示

セリア安定型ジルコニアとガンマアルミナを混合し、焼結した。そして電気泳動を行った。この研究から、電気泳動に適したセリア安定型ジルコニア／アルミナナノコンポジットをつくるには、1300℃で焼結することが有効であることがわかった。さらに、焼結後にガラス浸潤を行うと物性が向上した。

抄録全体を表示

金の高騰によって、陶材焼付け用合金としてCo-Cr合金が注目されているが、他の金属とCo-Cr合金について陶材焼き付け強度について検討したところ、金合金より劣るものの、Ni-Cr合金より強い焼き付け強度を示し、標準偏差も小さかった。

抄録全体を表示

Commercially Pure titanium (cpTi) and its alloys are frequently used for dental prosthetic devices. When they are used to restore anterior teeth, titanium prostheses are generally covered with an aesthetic material, retention beads are generally cast on the metal surface to promote mechanical retention – and this form of mechanical retention has the highest survival rate in clinical prostheses. We applier super critical water, alkaline treatment, and concentrated acid etching to titanium for enhancing the bonding strength between the titanium and the veneering resins. In this study, the effect of the concentrated acid-etching of cpTi on bonding strength to veneering dental porcelains was investigated according to ISO 9693.

抄録全体を表示

We investigated the bond strength between three-point and four-point flexure bond test for several dental metal-ceramic systems. Total six types of dental alloy, two types of each high-noble, base metal alloy, and titanium metal, were used to prepare metal-ceramic specimens with Vita VMK68 and Vita Titan porcelains according to their respective manufacturer instructions. Specimens for three-point flexure (3PF) and four-point flexure (4PF) bond test were tested in the same configurations according to ISO 9693 specification. There was a significant correlation between mean debonding loads tested by 3PF and 4PF (r2=0.95). Failure load of various dental metal-ceramic systems tested with specimen and test configurations by ISO 9693 was strongly influenced by mode of debonding failure and elastic modulus of metal substrate.

抄録全体を表示

Introduction: Fluorescence is the absorption of ultraviolet (UV) light (black light) by a substance and the spontaneous emission of visible light in the bluish spectrum within 10 ^-8 second of activation. The purpose of this study was to determine the fluorescent emission of all ceramic core, veneer and layered specimens with a color measuring spectrophotometer. Materials and Methods: The A2-corresponding shade of seven all ceramic core materials and 1 sintering ceramic as reference were prepared in clinically relevant thicknesses (0.4 to 0.8 mm). The A2- and A3-corresponding shades of each recommended veneer ceramic specimens were made to fabricate layered specimens that were 1.5 mm thick. Color of core, veneer and layered specimens was measured with a reflection spectrophotometer. An UV filter was positioned to 100% or 0% UV including condition. From the spectral reflectance values, the difference in reflectance by the inclusion (100% UV) and the exclusion (0% UV) of the UV component was calculated. Color difference (∆E*ab-FL) by the inclusion or the exclusion of the UV component was calculated. Two-way ANOVA with the fixed factors of the kind of ceramic and the brand/thickness combination within each kind on the color difference was performed (a=0.05). Results: ∆E*ab-FL value for core ceramics was 0.23 to 1.11 ∆E*ab units, that of veneer ceramics was 0.46 to 0.94 ∆E*ab units and that of layered specimens was 0.41 to 4.33 ∆E*ab units. ∆E*ab-FL value was significantly influenced by the kind of ceramic and the brand/thickness combination, and there was significant interaction between them. Discussion: Though the color difference by the inclusion or the exclusion of the UV component of the CIE standard illuminant D65 varied by the kind and brand of ceramics, clear fluorescent peaks in the differential spectral reflectance curves were not observed. Conclusions: All ceramic core and veneer ceramics investigated in the present study did not emitted fluorescence based on the protocol employed in this study. Further refinement of the measurement protocol is recommended.

抄録全体を表示

The catalyst effect of acetic acid, phosphoric acid and ammonia water adding to the 3-methacryloyloxypropyltrimethoxysilane were investigated. It was suggested that the 5.0vol% acetic acid, 5.0vol% phosphoric acid and 5.0vol% ammonia water added to 3-methacryloyloxypropyltrimethoxysilane had significantly higher coupling effect on modification of glass plates.

抄録全体を表示