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Takashi AKIYAMA, Atsufumi MANABE, Chihiro TANI, Yoichi TAKAHASHI, Kazu ...
2007 Volume 26 Issue 3 Pages
312-315
Published: 2007
Released on J-STAGE: February 06, 2009
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The aim of this study was to evaluate tri-ethylene glycol mono-methacrylate (TEGMA) in terms of dermatological allergic reaction using a Guinea Pig Maximization Test. Skin reaction was evaluated according to the criteria of International Contact Dermatitis Research Group. TEGMA, as a constituent in new primers, has been reported to contribute to a priming ability similar to that of highly purified glyceryl mono-methacrylate (GM). In this study, it was found that its adverse effect was less than that of 2-hydroxy ethyl methacrylate (2-HEMA), but similar to that of highly purified GM. In conclusion, it was anticipated that TEGMA would hereafter replace 2-HEMA as a primer, as it posed a lower risk of triggering dermatological allergic reaction.
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Hiroyuki MINAMI, Sayaka HORI, Hisanori KURASHIGE, Sadaaki MURAHARA, Ko ...
2007 Volume 26 Issue 3 Pages
316-322
Published: 2007
Released on J-STAGE: February 06, 2009
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The purpose of this study was to evaluate the effect of thermal cycling on the surface texture of restorative materials. Disk-shaped specimens made of seven resin composites (Beautifil: BF; Esthet-X: EX; Filtek Supreme: FS; Inten-S: IS; Point 4: PT; Solare: SR; and Venus: VS) were finished with 1-μm alumina suspension, and then thermocycled between 4 and 60°C in distilled water for 20,000 or 50,000 cycles with a dwell time of 60 seconds. Staining susceptibility and mean surface roughness, Ra, were examined, and surface texture was observed by scanning electron microscopy. Dye penetration test showed that the surfaces of all resin composites were more stained after thermal cycling. Mean Ra of all resin composites, except PT, significantly increased after 50,000 thermal cycles. Dislodgement of filler particles was observed for all resin composites after thermal cycling, except FS. It was concluded that thermal cycling significantly affected the surface texture of the seven examined resin composites.
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Yukinori MARUO, Goro NISHIGAWA, Morihiko OKA, Shogo MINAGI, Masao IRIE ...
2007 Volume 26 Issue 3 Pages
323-328
Published: 2007
Released on J-STAGE: February 06, 2009
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The aim of this study was to investigate how to achieve sufficient and stable adhesive strength between impression material and tray. Impression materials were molded between autopolymerizing resin columns, and tensile strength was measured as a function of these factors: tray storage time (1, 2, 4, 7, and 10 days), adhesive drying time (0, 1, 5, 10, and 15 minutes), and tray surface roughness (air abrasion, bur-produced roughness, and no treatment). Tensile bond strength was not affected by tray storage time throughout the entire evaluation period of 10 days. As for tray adhesive drying time, Reprosil and Exaimplant yielded extremely low values for drying times of 10 minutes or less (P<0.05), while Imprint II and Impregum were not influenced by drying time. Vinyl polysiloxane achieved the highest adhesive strength with bur-produced roughness, which was significantly higher than with air abrasion or no treatment (P<0.05), whereas polyether achieved the lowest value with bur-produced roughness (P<0.05). It was concluded that surface treatment of custom tray should be adapted to the type of impression material used to achieve optimum bond strength.
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Orhan Murat DOGAN, Selda KESKIN, Arife DOGAN, Hande ATAMAN, Ali USANMA ...
2007 Volume 26 Issue 3 Pages
329-334
Published: 2007
Released on J-STAGE: February 06, 2009
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With a view to understanding the structure-property relation of a silicone-based soft lining denture material after polymerization, its chemical composition and viscoelastic properties were investigated. Chemical compositions of the cured and uncured polymers of a commercial silicone permanent soft liner were determined by infrared spectroscopic analysis, nuclear magnetic resonance (NMR), and X-ray photoelectron spectroscopy. Dynamic mechanical analysis (DMA) method was used to investigate the viscoelastic behavior of the cured polymer of liner.
Spectroscopic analysis showed that the main component of soft liner was vinyl-terminated poly(dimethylsiloxane), and the adhesive was 3-methacryloxypropyltrimethoxy silane. NMR results revealed that other components included benzoyl peroxide as initiator for polymerization and also silicilic acid. Surface analysis by XPS provided interesting insights about the nature of adhesive bonding, as well as diffusion of silicilic acid through the matrix of the processed material and leaching-out. DMA results showed a two-phase character, and that the cured polymer was highly elastic.
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Sule KAVALOGLU CILDIR, Nuket SANDALLI
2007 Volume 26 Issue 3 Pages
335-341
Published: 2007
Released on J-STAGE: February 06, 2009
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The aim of this study was to investigate the compressive strength and surface roughness of two glass ionomer cements and two resin-based fissure sealants before and after fluoride release and recharge. Twenty-one specimens were prepared and divided into three groups for each material. First group was loaded in compression until failure. Fluoride released was measured from the remaining specimens, and then the second group of seven specimens was loaded at 28
th day. The remaining seven specimens were exposed to 0.05% NaF solution and 1.23% APF gel. Fluoride amount was measured, and the last group was loaded at 70
th day. Surface roughness measurement of five more disk-shaped specimens from each material was also carried out. After exposure to APF gel, all materials were recharged. At the end of experimental period, it was found that surface roughness increased, whereas compressive strength decreased, over time. In conclusion, fluoride-releasing fissure sealants could act as show, rechargeable fluoride release systems. However, if a fissure sealant exhibited high fluoride release, it had inferior mechanical properties.
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Akinari NAKAGAWA, Shigeki MATSUYA, Akari TAKEUCHI, Kunio ISHIKAWA
2007 Volume 26 Issue 3 Pages
342-347
Published: 2007
Released on J-STAGE: February 06, 2009
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Effects of added α-tricalcium phosphate (α-TCP) and β-TCP were investigated to shed light on the setting reaction of apatite cement (AC) consisting of tetracalcium phosphate (TTCP) and dicalcium phosphate anhydrous8 (DCPA). Added β-TCP showed no reactivity, and thus resulted in extended setting time and decreased mechanical strength. In contrast, α-TCP dissolved to supply calcium and phosphate ions after initial apatite crystal formation by the reaction of TTCP and DCPA. Although setting time was delayed because α-TCP was involved only in the latter reaction of apatite cement, larger apatite crystals were formed due to its addition. As a result of larger apatite crystal formation, the mechanical strength of α-TCP-added apatite cement increased by approximately 30%, as compared to α-TCP-free apatite cement.
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Toshiko INOUE, Takashi MIYAZAKI, Fumio NISHIMURA
2007 Volume 26 Issue 3 Pages
348-354
Published: 2007
Released on J-STAGE: February 06, 2009
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This study investigated the effects of thermal cycling on the tensile strength of dentin. Bovine dentin were divided into 10 groups, which were then subjected to various conditions: intact after preparation, thereby serving as a control; heating in boiling water for 45 minutes; 10,000 thermal cycles in water; 10,000 thermal cycles in PBS; storage in water at 5, 23, or 55°C for two weeks; and storage in PBS at 5, 23, or 55°C for two weeks. Subsequently, bovine dentin were trimmed into dumbbell-shaped specimens and the tensile test performed in distilled water at 37°C. Mean tensile strengths were compared statistically by one-way ANOVA and Fisher's PLTD test (p<0.05). Fracture surfaces were observed by scanning electron microscopy, and reliability of the results was analyzed with Weibull distribution. Tensile strength did not significantly change after thermal cycling or storage in water and PBS at all temperatures tested (71.2-77.0 MPa) but decreased after treatment with boiling water (65.5 MPa).
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Priyadarshanee Manorika RATNAWEERA, Toru NIKAIDO, Dinesh WEERASINGHE, ...
2007 Volume 26 Issue 3 Pages
355-360
Published: 2007
Released on J-STAGE: February 06, 2009
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The aim of this study was to evaluate the micro-shear bond strengths of two all-in-one adhesive systems to unground fluorosed enamel.
Buccal surfaces of 24 normal and 24 moderately fluorosed teeth (Thylstrup and Fejerskov index, TFI=4-6) were bonded using G-Bond and Clearfil Tri-S Bond. The surfaces were then restored with a resin composite, stored for 24 hours in water, and tested for micro-shear bond strength (MSBS). Fracture modes, etching patterns, and adhesive interfaces were studied under a scanning electron microscope (SEM). Data were analyzed with two-way ANOVA, whereby no significant differences in MSBS were found among the four groups (p>0.05). Through SEM examination, it was shown that 1 μm of resin tag-like extensions had penetrated into the enamel for both adhesives at the enamel-adhesive interface. Based on the results obtained, it was concluded that MSBS was not influenced by the severity of fluorosis. Furthermore, there were no differences in enamel bond strength between G-Bond and Clearfil Tri-S Bond.
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Irmgard HAUSER-GERSPACH, Eva M. KULIK, Roland WEIGER, Eva-Maria DECKER ...
2007 Volume 26 Issue 3 Pages
361-366
Published: 2007
Released on J-STAGE: February 06, 2009
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Bacterial adhesion to tooth surfaces or dental materials starts immediately upon exposure to the oral environment. The aim of this study, therefore, was to compare the adhesion of
Streptococcus sanguinis to saliva-coated human enamel and dental materials—during a one-hour period—using an
in vitro flow chamber system which mimicked the oral cavity. After fluorescent staining, the number of adhered cells and their vitality were recorded. The dental materials used were: titanium (Rematitan
® M), gold (Neocast 3), ceramic (Vita Omega 900), and composite (Tetric Ceram).
The number of adherent bacterial cells was higher on titanium, gold, and ceramic surfaces and lower on composite as compared to enamel. As for the percentage of adherent vital cells, it was higher on enamel than on the restorative materials tested. These results suggested that variations in the number and vitality of the adherent pioneer oral bacteria,
S. sanguinis, in the
in vitro system depended on the surface characteristics of the substratum and the acquired salivary pellicle.
The
in vitro adhesion model used herein provided a simple and reproducible approach to investigate the impact of surface-modified dental materials on bacterial adhesion and vitality.
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Mau-Chin LIN, Sheng-Chieh LIN, Yu-Tsai WANG, Suh-Woan HU, Tzu-Hsin LEE ...
2007 Volume 26 Issue 3 Pages
367-372
Published: 2007
Released on J-STAGE: February 06, 2009
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The purpose of this study was to evaluate the fracture resistance of Nd:YAG laser-welded cast titanium (Ti) joints with various clinical thicknesses and welding pulse energies. A four-point bending test was used to assess the effects of various specimen thicknesses (1-3 mm) and welding pulse energies (11-24 J) on the fracture resistance of Nd:YAG laser-welded Ti dental joints. Fracture resistance was evaluated in terms of the ratio of the number of fractured specimens to the number of tested specimens. As for the fracture frequencies, they were compared using the Cochran-Mantel-Haenszel test. Morphology of the fractured Ti joints was observed using a scanning electron microscope. Results showed that decreasing the specimen thickness and/or increasing the welding pulse energy,
i.e., increasing the welded area percentage, resulted in an increase in the fracture resistance of the Ti joint. Where fracture occurred, the fracture site would be at the center of the weld metal.
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Takashi NEZU, Tomohiro MORIKAWA, Kaori SASAKI, Setsuo SAITOH, Masayuki ...
2007 Volume 26 Issue 3 Pages
373-381
Published: 2007
Released on J-STAGE: February 06, 2009
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Effects of hydrophobic environment adjusted by various alcohols on the structural stability of calfskin collagen (CSC) were studied to elucidate the nature of collagen-monomer interaction in adhesion. The stability of CSC in aqueous alcohol solutions was represented by its denaturation temperature,
Td, measured by DSC. The hydrophobicity of the alcohol solutions was quantified with their specific dielectric constants, ε
r, calculated from their concentrations. The effect of each alcohol to stabilize or destabilize CSC was evaluated by the initial slope of each
Td vs. ε
r plot, denoted as -(d
Td/dε
r)
ini and termed as stabilization power. Results showed that a hydrophobic environment with a smaller ε
r lowered the stabilization power. Stabilization power ranged from -3 (strong destabilization) for phenol (ε
r=12) to +0.3 (weak stabilization) for glycerol (ε
r=47). In view of the encouraging results obtained in this study, the new index was therefore helpful in predicting the effects of new dental materials of known ε
r values on the stability of dentinal collagen.
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Norihiro NISHIYAMA, Masahiro AIDA, Kou FUJITA, Kazuomi SUZUKI, F.R. TA ...
2007 Volume 26 Issue 3 Pages
382-387
Published: 2007
Released on J-STAGE: February 06, 2009
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Three experimental self-etching primers—consisting of N-methacryloyl-ω-aminoalkyl phosphonic acid (NMωP) with different methylene chain lengths and N-methacryloyl glycine (NMGly)—were formulated. The influence of methylene chain length in NMωP derivatives on the chemical nature of calcium salts was examined following their application to tooth components. Bond strengths of experimental self-etching primers created with these monomers to enamel and dentin were also investigated. Nuclear magnetic resonance spectroscopy showed that NMωPs decalcified tooth components with formation of calcium salts, which changed from calcium hydrogen phosphonate to calcium phosphonate with increase in methylene chain length within the NMωP structure. Disparity in calcium salt formation was related to increases in bond strength to enamel from 18 to 24 MPa. However, bond strength to dentin remained unchanged (22 MPa). The relative dependency of bond strength on monomer methylene chain length was probably attributable to the sites where these NMωP calcium salts had deposited on the bonding substrates.
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Kazushi YOSHIKAWA, Douglas T CLARK, Susan R BRAILSFORD, David BEIGHTON ...
2007 Volume 26 Issue 3 Pages
388-392
Published: 2007
Released on J-STAGE: February 06, 2009
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MDPB, 12-methacryloyloxydodecylpyridinium bromide, was tested for its ability to inhibit the growth of organisms associated with active root caries lesions and to modify the growth characteristics of these organisms at sub-MICs. MICs and MBCs of MDPB for independent isolates (n=5) of the following taxa:
Streptococcus mutans, Streptococcus oralis, Streptococcus salivarius, Actinomyces naeslundii, Actinomyces israelii, Actinomyces gerensceriae, Actinomyces odontolyticus, Lactobacillus spp., and
Candida albicans were determined, and the effects at sub-MIC on microbial growth kinetics were assessed. All isolates were sensitive to inhibition by MDPB. The median MICs and MBCs of MDPB for these organisms were in the range of 3.13 to 25.0 μg/ml and 6.25 to 50.0 μg/ml, respectively. As for the influence of pH, inhibition was sensitive to acidic pH. Even at sub-MICs, the growth of all strains, measured as cell yield and doubling time, was significantly reduced. Based on the results of this study, MDPB exhibited the potential to inhibit the growth of microbiota associated with active root caries lesions.
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Norihisa OHASHI, Hiroyasu KOIZUMI, Yumi ISHIKAWA, Mika FURUCHI, Hideo ...
2007 Volume 26 Issue 3 Pages
393-400
Published: 2007
Released on J-STAGE: February 06, 2009
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The purpose of this study was to evaluate the influence of heating, cast bonding, and subsequent polishing procedures on attractive force of magnetic attachments. Two magnetic attachment systems with keepers of different chemical compositions (Hicorexslim 3013, 447J1; Magfit EX400, AUM20) were employed. Keepers examined were: (1) untreated; (2) heated; (3) cast-bonded with Ag-Pd alloy; (4) cast-bonded with Ag-Pd alloy and polished; (5) cast-bonded with gold alloy; and (6) cast-bonded with gold alloy and polished. Attractive force was determined with a force gauge, and surface structure was evaluated with scanning laser and electron microscopes. Attractive force of the Hicorex system was reduced by cast bonding, whereas that of the Magfit system was reduced by both heating and cast bonding. However, attractive force of both systems was somewhat recovered through the polishing process. Based on the findings of this study, it was suggested that careful polishing after cast bonding was indispensable to the recovery of attractive force for both attachment systems.
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Karl-Thomas WRBAS, Jörg Fabian SCHIRRMEISTER, Markus Jörg AL ...
2007 Volume 26 Issue 3 Pages
401-408
Published: 2007
Released on J-STAGE: February 06, 2009
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The aim of this study was to evaluate the effects of post surface conditioning with adhesive systems on tensile bond strength between two composite resin core systems and FRP posts (ER DentinPost). Forty-eight posts were trimmed at the coronal part, and the upper part of 3 mm was covered with a standardized composite resin core build-up. Twenty-four posts were treated with the respective adhesive systems. Four groups were formed: G1—ClearfilCore; G2—Clearfil New Bond + ClearfilCore; G3—MultiCore Flow; and G4—AdheSE + MultiCore Flow. Mean (SD) bond strengths in MPa were 7.53 (0.89) for ClearfilCore and 8.08 (0.93) for New Bond + ClearfilCore; 5.80 (0.39) for MultiCore Flow and 5.92 (0.43) for AdheSE + MultiCore Flow. ClearfilCore achieved significantly higher bond strengths than MultiCore Flow (two-way ANOVA; p<0.0001). In conclusion, composite resin core materials exerted a significant influence on tensile bond strength, while adhesive systems did not significantly affect the results.
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Maki OSHIRO, Hiroyasu KUROKAWA, Susumu ANDO, Atsushi IROKAWA, Masashi ...
2007 Volume 26 Issue 3 Pages
409-413
Published: 2007
Released on J-STAGE: February 06, 2009
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The purpose of this study was to determine the elastic modulus of enamel during bleaching procedure with the use of an ultrasonic device. Enamel sections were obtained from freshly extracted bovine incisors. Specimens were exposed to 10% carbamide peroxide for two hours, followed by an application of a fluoride-containing toothpaste for five minutes and stored in artificial saliva (pH 7.0). An ultrasonic device was used to measure the sound velocities of longitudinal and shear waves as well as elastic modulus. The mean elastic modulus of bleached enamel decreased with time, from 15.5 GPa to 10.1 GPa. Conversely, the elastic modulus of bleached enamel followed by application of a fluoride-containing toothpaste increased with time, from 15.2 GPa to 20.2 GPa. Results of this study indicated that a decrease in elastic modulus associated with bleaching occurred, and that fluoride-containing toothpaste reversed this effect.
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Yasuhiro MATSUDA, Yukie MURATA, Toru TANAKA, Hisanori KOMATSU, Hidehik ...
2007 Volume 26 Issue 3 Pages
414-421
Published: 2007
Released on J-STAGE: February 06, 2009
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To the end of developing a convenient research tool to calculate the mineralization status of teeth in detail, a new program was developed using Visual Basic for Applications combined with Microsoft Excel 2004. To demonstrate the usefulness of this program, it was used to analyze tooth enamel mineralization after acid exposure. Transverse microradiography images (TMR) of specimens were digitalized with a charge-coupled device camera with a microscope (CCD camera) and a digital film scanner (FS). Subsequently, the mineral content profile of each specimen after de- and remineralization studies were calculated using the Angmar's formula. The newly developed program was applied to calculating the mineral loss (ΔZ), lesion depth (Ld), surface zone depth (SZd), and lesion body depth (LBd) of tooth specimens. In addition, the outer surface zone (OSZ), inner lesion body (ILB), and sandwich area (SA) between OSZ and ILB—which together constituted ΔZ—were calculated by the newly developed program. Data obtained with the newly developed program were in good agreement for both CCD camera and FS, indicating that the program was reliable for tooth enamel mineralization research studies.
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Ahmed Samir BAKRY, Alireza SADR, Hidekazu TAKAHASHI, Masayuki OTSUKI, ...
2007 Volume 26 Issue 3 Pages
422-428
Published: 2007
Released on J-STAGE: February 06, 2009
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The purpose of this study was to investigate the chemical characteristics of dentin after Er:YAG laser irradiation using various output energies with or without water irrigation. Analysis was carried out by means of attenuated total reflectance Fourier transform infrared spectroscopy (FT-IR/ATR) and X-ray diffraction (XRD). Furthermore, the relative infrared peak intensities of dentin specimens were compared statistically. Results showed that Er:YAG laser with an output energy of 100 mJ/pulse with water irrigation did not cause any detectable change in dentin. However, a higher energy output or the absence of water irrigation affected the organic portion of dentin. With XRD, no obvious phase changes were observed between the XRD pattern of the control (non-irradiated) dentin powder and those after Er:YAG irradiation—regardless of Er:YAG laser output energy or dehydration condition. It was suggested that the intrinsic water content of dentin—together with extrinsic water irrigation—were important factors to achieving the desired outcome of dentin ablation by Er:YAG laser.
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Mamoru MURAKAMI, Naotsugu KAWAHATA, Eiichi NAGAOKA
2007 Volume 26 Issue 3 Pages
429-436
Published: 2007
Released on J-STAGE: February 06, 2009
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The aim of this study was to develop a three-dimensional method to analyze edentulous ridge shapes.
A laser projection method was used to record the shape of edentulous plaster models. Contour of residual ridge on the reconstructed image was then subdivided into small triangles, and a ‘normal line’ representing the center of gravity of each triangle was determined buccolingually and anteroposteriorly. Angle between the normal line on the residual ridge and the tentative occlusal plane was calculated for each triangle. These angles were then used to analyze the ridge shape.
This method was used to analyze the ridges of 20 edentulous patients with excessive bone resorption. The results suggested that this method was useful for analyzing edentulous ridges regardless of ridge shape and degree of resorption.
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Takeshi SHIBATA, Nobushiro HAMADA, Katsuhiko KIMOTO, Tomofumi SAWADA, ...
2007 Volume 26 Issue 3 Pages
437-444
Published: 2007
Released on J-STAGE: February 06, 2009
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The purpose of this study was to develop an acrylic resin with antifungal properties by leveraging the photocatalytic activity of apatite-coated titanium dioxide (Ap-TiO
2).
Candida albicans was used for antifungal activity assay of the specimen plates under ultraviolet A (UVA) with a black light source. Statistically significant decreases in cell viability in acrylic resins containing 5 wt% and 10 wt% Ap-TiO
2 were observed after irradiation for two, four, and six hours (P<0.01), when compared to the control. As for the flexural strength and modulus values of acrylic resins mixed with Ap-TiO
2 and TiO
2 particles, they varied before and after irradiation. Among the tested specimens, a 5 wt% content of Ap-TiO
2 in acrylic resin exceeded the requirements of ISO 1567. It was thus suggested that acrylic resin containing 5 wt% Ap-TiO
2 could exert antifungal effects on
C. albicans, while at the same time maintain adequate mechanical properties for clinical use.
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Nipaporn WATTANAWONGPITAK, Takako YOSHIKAWA, Michael F BURROW, Junji T ...
2007 Volume 26 Issue 3 Pages
445-450
Published: 2007
Released on J-STAGE: February 06, 2009
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This study evaluated the effect of thermal stress on marginal sealing and cavity wall adaptation using two adhesive systems. Cylindrical cavities were prepared in superficial dentin of bovine incisors and bonded with Clearfil SE Bond or Single Bond adhesive. Cavities were bulk-filled with Photo Clearfil Bright or Filtek Flow resin composite and light-cured for 40 seconds. Specimens were thermocycled for 0, 500, or 5000 times. A dye penetration test was carried out to determine adaptation to the cavity wall. Dye penetration length was calculated as a percentage of the total cavity wall length. Clearfil SE Bond showed excellent marginal sealing and cavity wall adaptation regardless of composite type up to 500 cycles of thermal stress. As for the Single Bond groups, significantly greater marginal leakage occurred after 500 cycles. At 5000 cycles of thermal stress, both adhesive systems showed significantly decreased marginal integrity compared with the 0 cycle group.
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Masao YOSHINARI, Kenichi MATSUZAKA, Sadamitsu HASHIMOTO, Kazuyuki ISHI ...
2007 Volume 26 Issue 3 Pages
451-456
Published: 2007
Released on J-STAGE: February 06, 2009
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Simvastatin acid (SVA) has been reported to stimulate bone formation by increasing expression of BMP-2 in osteoblasts. Due to their multi-functional characteristics and bioadaptability, cyclodextrins (CDs) are capable of forming inclusion complexes with many drugs by including a whole drug molecule inside their cavity. In the present study, we prepared SVA/CD inclusion complex solutions with different pH values. These were then used to determine their SVA release behavior after coating on titanium substrates, as well as to clarify the characteristics of SVA/CD complexes
per se. Results showed that the lower the pH value of the solution, the lower the release kinetics of SVA. Besides, the amount of crystalline complexes in the coatings increased with decrease in pH. These results suggested that the release rate of SVA depended on two factors: pH of the solution and concomitant crystallinity of the coating.
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Hisako HIRAGUCHI, Hisami NAKAGAWA, Masahiro KAKETANI, Hideharu HIROSE, ...
2007 Volume 26 Issue 3 Pages
457-462
Published: 2007
Released on J-STAGE: February 06, 2009
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This study investigated the effects of disinfection of combined agar/alginate impressions on the dimensional accuracy of resultant stone casts. Impressions of a master cast designed to simulate an abutment tooth were prepared by combining each of two brands of cartridge-form agar impression materials with an alginate impression material. The impressions were immersed in 1% sodium hypochlorite for 10 minutes or 2% glutaraldehyde for 30 minutes. The remaining impressions were sprayed with these two disinfectants and then stored in sealed bags for 10, 30, 60, and 120 minutes. Stone casts obtained from the non-disinfected impressions were also prepared as control. Changes in diameter of the stone casts were then measured. Results indicated that storage for 10 minutes after spraying with 1% sodium hypochlorite was an appropriate disinfection method for combined agar/alginate impressions, as well as immersion in 1% sodium hypochlorite for 10 minutes.
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