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Volkan TURP, Betul TUNCELLI, Deniz SEN, Gultekin GOLLER
2012 年 31 巻 6 号 p.
891-902
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The aim of this study was to evaluate the effects of pH changes in the oral cavity on the mechanical properties of zirconia and feldspathic ceramics. Bilayered zirconia-feldspathic samples were prepared from three different commercial brands of Y-TZP blocks: Zirkonzahn, Cercon, and Everest. Samples were stored in artificial saliva with different pH values (3.5, 7.0, and 10.0) for 10 days at 37°C. Flexural strength, Vickers hardness, and fracture toughness were calculated after samples were subjected to biaxial flexure test. Microstructural analysis of the materials was also performed.Data were analyzed by one-way analysis of variance (ANOVA), and multiple comparisons were performed using Tukey's test (α=0.05). Acidic and alkaline environments adversely affected the mechanical properties of zirconia, resulting in material degradation, loss of stabilizer content, and increase in tetragonal-monoclinic phase transformation. Commercial dental zirconia blocks have varied mechanical properties, but they are generally susceptible to degradation when exposed to corrosive environments.
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Xinjing ZHANG, Xiuyin ZHANG, Bangshang ZHU, Kaili LIN, Jiang CHANG
2012 年 31 巻 6 号 p.
903-908
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The aim of this study was to investigate the mechanical and thermal properties of denture polymethyl methacrylate (PMMA) reinforced with aluminum borate whiskers (ABWs). To improve bonding between ABWs and PMMA matrix, the surface of ABWs was modified with a silane coupling agent. Varied contents of silanized ABWs —ranging between 1 and 20 wt%— were mixed into the PMMA resin matrix to prepare ABW/PMMA composites, which were subjected to three-point bending test, Vickers hardness test, and thermal analysis. Silanized ABWs improved the flexural strength, surface hardness, and thermal stability of PMMA. Optimal amount of ABWs in the PMMA matrix was 5 wt%, which provided the ABW/PMMA with maximum reinforcement.
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Sai MA, Satoshi IMAZATO, Ji-hua CHEN, Gen MAYANAGI, Nobuhiro TAKAHASHI ...
2012 年 31 巻 6 号 p.
909-915
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The purpose of this study was to evaluate the ability of a coating material containing the surface pre-reacted glass-ionomer (S-PRG) filler to protect the root from demineralization
in vitro. The proprietary coating resin containing the S-PRG filler (PRG Barrier Coat) was applied to human root dentin and immersed in acid buffer at pH 4.5 for 3 d. Demineralization was evaluated by micro-CT scanning and the dentin-material interface observed by scanning electron microscopy. The ability of the coating resin to modify acid production by
Streptococcus mutans was investigated by monitoring pH using an ion-sensitive field-effect transistor pH electrode. Application of PRG Barrier Coat produced a coating layer with the thickness of approximately 200 µm and completely inhibited demineralization. The bacteria-induced pH fall at the material surface was significantly inhibited. We conclude that S-PRG fillercontaining coating resin may be an effective material for protecting exposed root from both chemical and biological challenges.
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Christian MELLER, Christian KLEIN
2012 年 31 巻 6 号 p.
916-923
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The objective was to assess the fluorescence properties of current commercial resin composites. Sixteen light-curing resin composites, representing a total number of 241 shades, were analyzed. Fluorescence measurements of all samples were taken using the monochromator-based fluorescence reader Synergy
TM Mx (BioTek Instruments Inc. ). Additionally, samples of dentin and enamel were analyzed for comparison. The mean of the maximum excitation wavelength was (398±5) nm and the mean of the resulting emission wavelength was (452±9) nm for all composite shades. The maximum fluorescence varied widely between 50 and 70,808 RFU with a mean of (28,948±15,380) RFU. The maximum for dentin was (9,308±3,676) RFU and enamel (5,467±506) RFU. The results showed that the analyzed composites fluoresced at nearly the same excitation-emission wavelengths combination but with varying optical intensities. These results provide useful reference for optimal fluorescence induction and may help to develop better fluorescence diagnostic methods needed for treatment, forensic investigations and epidemiological research/analyses.
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Theodora BRAVIS, Peter PILECKI, Ron F. WILSON, Michael FENLON, Timothy ...
2012 年 31 巻 6 号 p.
924-932
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The effect of loading on microleakage and microtensile bond strength of MOD composite restorations bonded with either self-etching or etch-and-rinse adhesive was investigated. MOD cavities were prepared in 28 extracted molar teeth. 14 teeth were bonded with a one-step self-etching adhesive (G-Bond) and 14 with an etch-and-rinse adhesive (Optibond Solo Plus) then restored with resin composite. For each adhesive, 7 teeth were loaded and 7 unloaded (controls). Loading was achieved with an axial force of 80 N at 2.5 cycles/s for 250,000 cycles. All the teeth were stored in 0.25% rhodamine solution for 24 h and sectioned in a bucco-lingual direction at the proximal boxes to examine microleakage then further sliced mesiodistally into beams for the μTBS test. Failure modes were determined using confocal and scanning electron microscopy. ANOVA assessed the effect of loading on microleakage and bond strength. After loading, restorations bonded with G-Bond exhibited significantly greater dye penetration compared to Optibond Solo Plus at both the axial walls and cavity floor. On the other hand, loading significantly reduced the μTBS of Optibond Solo Plus, whereas it had no significant effect on the μTBS of G-Bond.
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Mau-Chin LIN, Kuo-Lung TUNG, Sheng-Chieh LIN, Her-Hsiung HUANG
2012 年 31 巻 6 号 p.
933-940
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
This study investigated the bonding of dental porcelain to non-cast Ti surface with different treatments. Mechanically ground non-cast Ti strips, simulating surface conditions produced by CAD/CAM, were Al
2O
3-sandblasted, then subjected to different surface treatments, including immersion in HNO
3-containing acid, NaOH-containing alkaline, and NaOH-containing alkaline then HNO
3-containing acid. Ti-porcelain specimens preparations and their bend strength measurements were based on ISO 9693. Ti surface treatment changed not only surface roughness but also surface chemistry, leading to influence on bond strength. Bond strengths of all Ti-porcelain groups were higher than ISO 9693 minimum requirement. The sandblasted/acid-treated Ti surface showed the highest bond strength (34.60 MPa) with porcelain; no significant difference in bond strength (27.92-29.63 MPa) was found among other Tiporcelain groups. All Ti-porcelain specimens showed adhesive bond failure. Bonding between non-cast Ti and dental porcelain was strengthened by a simple and practical sandblasting/acid-etching treatment of the Ti surface prior to porcelain sintering.
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Keisuke NAKAMURA, Yasutomo YAMADA, Yukyo TAKADA, Takayuki MOKUDAI, Hir ...
2012 年 31 巻 6 号 p.
941-946
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The purpose of the present study was to evaluate the corrosive effect of disinfection solution containing hydroxyl radicals generated by photolysis of H
2O
2on dental metals. Static immersion test was performed on four different dental metals: Ti, Type 316L stainless steel, Ag-Pd-Cu-Au alloy, and Co-Cr alloy. Metal specimens were immersed in 1 M H
2O
2(=3.4%) with or without light-emitting diode (LED) light irradiation (wavelength: 400 nm) for 1 week, and then the amounts of released ions were analyzed. Corrosive effect of the disinfection solution containing hydroxyl radicals on any dental metals tested in the present study never exceeded that of H
2O
2 alone. Therefore, disinfection systems based on the photolysis of H
2O
2 for the cleaning of dentures and treatment of oral infectious diseases would not cause problematic metal corrosion whenever the concentration of H
2O
2 does not exceed 3%, which is a concentration used as an oral disinfectant.
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Eren İŞMAN, Emine Şirin KARAARSLAN, Rıdvan OKŞAYAN, Ali Rıza TUNÇDEMİR ...
2012 年 31 巻 6 号 p.
947-953
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
This study evaluated the shear bond strength (SBS) of a traditional orthodontic bracket bonding agent (Transbond XT) against two self-etch, self-adhesive systems (Maxcem Elite and Vertise Flow). Sixty premolar teeth and sixty brackets were randomly and equally divided into five groups: Transbond XT (TXT) as the control, Maxcem Elite (ME) without etching, ME with etching (ME/ Etch), Vertise Flow (VF) without etching, and VF with etching (VF/Etch). Respective SBS results of the five groups were 9.86±3.20, 4.67±2.94, 7.82±2.56, 2.55±0.77, and 7.89±1.17 MPa. SBS values of the new self-etch adhesive systems were significantly lower than the traditional etch-and-rinse control (
p<0.005). However, no significant differences were found between TXT and the self-adhesives applied with etching (
p>0.005). After debonding, ARI scores “0" and “1" were predominant in non-etched ME and VF groups. It was concluded that new self-etch, self-adhesive bonding systems require additional phosphoric acid application to achieve comparable SBS values as the traditional orthodontic bonding agent.
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Ryosuke MURAYAMA, Tetsuya FURUICHI, Miho YOKOKAWA, Fuminori TAKAHASHI, ...
2012 年 31 巻 6 号 p.
954-959
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
This study investigated the effect of a coating material containing S-PRG fillers on the demineralization of bovine enamel and dentin, by measuring changes in the transmitted ultrasonic velocity. Bovine enamel and dentin specimens with and without coating (
n=6 for each condition) were cut into blocks, immersed in 0.1 M lactic-acid buffer solution (pH 4.75) for 10 min twice daily throughout the test period, and stored in a demineralising artificial saliva solution (pH 7.0) between treatments. The propagation time of longitudinal ultrasonic waves was measured by a pulser-receiver with a transducer. Data were evaluated using ANOVA followed by Tukey's HSD test (α=0.05). The sonic velocity decreased over time for specimens stored in demineralising solution; however, coated specimens had a significantly higher sonic velocity than those without coating. The coating material containing pre-reacted glass-ionomer fillers therefore appeared to reduce the demineralisation of enamel and dentin.
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Hiroshi KANO, Tadafumi KUROGI, Takaharu SHIMIZU, Masahiro NISHIMURA, H ...
2012 年 31 巻 6 号 p.
960-968
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
We evaluated adhesion strength to acrylic resins under various experimental conditions and viscosity of 4 cream-type denture adhesives and 2 mouth moisturizers. The viscosity was determined by a sine-wave vibro viscometer. The adhesion strength tests were performed with 2 resin plates at a universal tester. In Method A, various constant thicknesses of material layer were tested and tensile strength was measured, while in Method B a constant load was applied before measurement. Five tests were carried out for each measurement. With Method A, adhesion strength increased exponentially as the layer got thin. Effect of the material thicknesses (contribution ratio ρ=79.0%) was much larger than that of material type (ρ=15.3%). Materials with higher viscosity had greater levels of adhesion strength in Method A, whereas those with the higher viscosity had lower levels of adhesion strength in Method B. Adhesion strength was significantly affected by the experimental condition prior to applying tension.
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Monica MATTIOLI-BELMONTE, Giovanna ORSINI, Francesca GIULIODORI, Adria ...
2012 年 31 巻 6 号 p.
969-974
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
This study evaluated a new automated system using alternative irrigants for root canal cleaning treatments. This method relies on a system inserting an enzymatic solution based on Trypsin flowing inside the pulp chambers and root canals, completely avoiding traditional endodontic instrumentation. Sixty freshly extracted human molar teeth were randomly divided into 4 groups to assess 3 regimens (R1-3) differing in 0.25% Trypsin/EDTA and 5% Sodium Hypochlorite (NaOCl) solutions administration. Scanning electron microscopy observations and scores taking into account changes in dentin tubules were used to assess treatment effects in pulp chambers and roots. Significant changes in root cleaning ability relative to administration timing were observed, with the best results found in R3, with scheduled alternated cycles of Trypsin/EDTA and NaOCl inside the tooth. The non-invasive root canal method demonstrates good teeth cleaning ability independent of root morphology. This equipment may provide lower discomfort levels for patients undergoing endodontic treatment.
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Şebnem KURŞUN, Gül DINÇ, Bengi ÖZTAŞ, Selcen YÜKSEL, Kıvanç KAMBUROĞLU
2012 年 31 巻 6 号 p.
975-979
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
This study investigated the visibility of secondary caries lesions associated with two different adhesive systems of composite restorations (Optibond Solo Plus and Clearfil SE Bond) using a conventional dental x-ray film (Kodak D Speed) and a digital system (Digora) based on storage phosphor-plate technology for detection of secondary caries. For imaging techniques and adhesive systems, false positive scores were high. Intraobserver agreements ranged between 0.432 and 0.778, while interobserver agreements for the readings ranged 0.321-0.731 and 0.411-0.701, respectively. No statistical difference was found between the Az (area under curve) values obtained from PSP (photostimulable storage phosphor) and film images with the exception of the second observer's first reading for total etch adhesive system (Optibond Solo Plus) (
p=0.0258). Furthermore, no statistical difference was found between both the bonding systems assessed (
p>0.05). Adhesive materials should also have enough radiopacity to facilitate diagnosis of secondary caries.
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Keisuke KAMBARA, Masatoshi NAKAJIMA, Keiichi HOSAKA, Masahiro TAKAHASH ...
2012 年 31 巻 6 号 p.
980-987
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The purpose of this study was to compare the dentin bond strength of three self-adhesive cements with smear layer pretreatments using a calcium-chelating agent (EDTA) and deproteinizing solution (NaOCl) and to evaluate their interfacial characteristics. Smear layer-covered dentin surfaces were pretreated with EDTA for 60 s, NaOCl for 5 and 15 s, or none. Three self-adhesive cements; Clearfil SA luting (Kuraray Medical), Rely X Unicem clicker (3M ESPE) and Breeze (Pentron) were applied to the dentin surfaces. After 24-h water storage, shear bond strengths to dentin were determined. In addition, nanoleakage evaluation at the interface was performed using FE-SEM and EDS. EDTA-pretreatment significantly improved the bond strength of BR (
p<0.05) and NaOCl-pretreatment for 15 s significantly improved the bond strength of RX (
p<0.05). On the other hand, for SA, both pretreatments significantly decreased bond strength to dentin (
p<0.05). Nanoleakage formation was observed in various amounts at the cement-dentin interfaces.
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Luca MARIGO, Carlo LAJOLO, Raffaella CASTAGNOLA, Daniele ANGERAME, Fra ...
2012 年 31 巻 6 号 p.
988-994
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The aim of this study was to perform a morphometric evaluation of the resin-root canal dentine interface of four “etch and rinse" adhesive systems. Forty human teeth were restored through a fiber post insertion using: Group 1: XP Bond adhesive; Group 2: Prime & Bond NT; Group 3: Surgi Prime Bond adhesive; Group 4: Scotchbond Multi-Purpose Plus. Two cross-sections (apical and coronal) were obtained and analyzed in morphological confocal laser scanning microscope. The numbers of resin tags (RT) and the thickness of the hybrid layer (HL) were evaluated. Quantitative variables were tested by a Shapiro-Wilk test. Parametric variables by an Anova test. Group 4 produced the thickest HL and Group 1 showed the thinnest. Considering RT, Group 1 produced the highest density, while Group 3 the lowest density. All the adhesives produced good results in terms of HL thickness and RT density.
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Nurazreena AHMAD, Kanji TSURU, Melvin L. MUNAR, Michito MARUTA, Shigek ...
2012 年 31 巻 6 号 p.
995-1000
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The effect of the solubility of the precursors, alpha tricalcium phosphate (α-TCP) and beta tricalcium phosphate (β-TCP) on the mechanical strength of hydroxyapatite (HAp) bone substitute was investigated. Uniaxially pressed block starting from these precursors were treated hydrothermally with 1 mol/L of ammonia solution at 200°C for various durations. XRD analysis revealed that α-TCP block took 3 h whereas β-TCP block took 240 h for complete transformation to HAp. The porosity of HAp obtained from β-TCP block was found to be lower than that of HAp from α-TCP block. Diametral tensile strength of HAp from β-TCP block showed a significantly higher value than that of HAp from α-TCP block. It is therefore concluded that solubility of precursor affects the mechanical strength of the HAp block.
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Takashi KAMEDA, Kazuo OHKUMA, Natsuki SANO, Hideo OGURA, Kazuto TERADA
2012 年 31 巻 6 号 p.
1001-1007
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
Very weak electrical, magnetic and ultrasound signal stimulations are known to promote the formation, metabolism, restoration and stability of bone and surrounding tissues after treatment and operations. We have therefore investigated the possibility of intraoral generation of electricity and magnetism by occlusal force in an
in vitro study. Biting bimorph piezoelectric elements with lead zirconate titanate (PZT) using dental models generated appropriate magnetism for bone formation,
i. e. 0.5-0.6 gauss, and lower electric currents and higher voltages,
i. e. 2.0-6.0 μA at 10-22 V (appropriate levels are 30 μA and 1.25 V), as observed by a universal testing machine. The electric currents and voltages could be changed using amplifier circuits. These results show that intraoral generation of electricity and magnetism is possible and could provide post-operative stabilization and activation of treated areas of bone and the surrounding tissues directly and/or indirectly by electrical, magnetic and ultrasound stimulation, which could accelerate healing.
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Nesreen SALIM, Julian SATTERTHWAITE, Riina RAUTEMAA, Nick SILIKAS
2012 年 31 巻 6 号 p.
1008-1013
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
This study investigated the impact of impregnation of a poly(ethyl methacrylate) /tetrahydrofurfuryl methacrylate (PEM/THFM) polymer with chlorhexidine or fluconazole on the degree of conversion (DC) and colour stability (ΔE). The DC of uncured (0 h) and cured (24 h) samples was analysed by Fourier transform infrared spectroscopy (FTIR) and colour stability was analysed colorimetrically. The DC percentage of the control samples was significantly greater than those containing chlorhexidine and fluconazole (
p≤0.05). The control discs exhibited only slight colour change compared to the impregnated discs which showed marked colour change (
p≤0.05). A strong negative correlation between the extent of colour change and the degree of conversion was detected (r=0.97). The DC and colour stability were influenced by the addition of chlorhexidine or fluconazole. However, the final values were comparable to other commonly used acrylic liners and within acceptable ranges. PEM/THFM can be considered as a biocompatible drug delivery system.
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Mitsunori YAMAMOTO, Harumasa WANIBE, Kazuhiko NAKATA, Shozo TSURUTA, T ...
2012 年 31 巻 6 号 p.
1014-1020
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The purpose of this study was to examine the apatite-formation ability and the viscosity of a mineral trioxide aggregate (MTA)polyvinyl alcohol (PVA) paste prepared. The MTA-PVA paste immersed in an artificial body fluid generated carbon apatite containing magnesium. The MTA-PVA paste exhibited fluidity and increased compressive strengths. It was considered possible to adjust the apparent viscosity of MTA paste by changing the concentration of the PVA solution. The MTA-PVA paste obtained using a 3-10 wt% PVA solution displayed a structural viscosity. The use of MTA may be elevated by the MTA-PVA paste with syringes in the field of endodontic treatment in order to improve MTA's operability.
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Iranzihuatl TORRES-GALLEGOS, Gabriel A. MARTINEZ-CASTAÑON, Juan-Pablo ...
2012 年 31 巻 6 号 p.
1021-1027
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The aim of this study was to evaluate the bond strength of three adhesive systems: Excite™, Adper Prompt L-Pop™ and AdheSE One™ to varying degrees of fluorotic enamel using micro-tensile bond strength (μTBS) tests. Human enamel was classified according to the Thylstrup and Fejerskov Index. The interface resin-enamel was observed using stereoscopic and electron microscopy. The Excite™, achieved the highest μTBS when bonded to healthy enamel and decreased as the degree of fluorosis increased (
p<0.05). The Prompt L-Pop™ improved the bonding on moderate and severe fluorosis. The μTBS of the AdheSE One™, was significantly lower in all degrees of fluorotic enamel (
p<0.05) indicating a very poor bonding ability to enamel. These results will provide clinicians with preliminary data to assist them in the selection of the most effective adhesive systems for treatment of fluorosis enamel, resulting in more successful restorative care.
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Zeliha YILMAZ, A. Lale DOGAN, Ozgur OZDEMIR, Ahmet SERPER
2012 年 31 巻 6 号 p.
1028-1032
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The purpose of this study was to evaluate the cytotoxic effects of commercially available root canal sealers [Sealite Ultra (SU), Tubli-Seal (TS), Tubli-Seal EWT (TS-EWT), Pulp Canal Sealer (PCS), Pulp Canal Sealer EWT (PCS-EWT), Endomethasone N (En N), and Apexit Plus (AP)] on L929 cells by using MTT assay. After incubation with each sealer's extract at 37°C in a humidified air atmosphere containing 5% CO
2 for 24 h, MTT (5 mg/mL) in saline was added into each well and further incubated at 37°C for 4 h. Formazan precipitate was dissolved in a buffer containing 23% sodium dodecyl sulfate and 50%
N,
N-dimethylformamide (pH 4.7). Optical densities of dissolved formazan were read using a microplate spectrophotometer. AP, TS, and TS-EWT showed no cytotoxicity at any dilution tested. Other sealers exhibited some degree of cytotoxicity at the 1/4 and 1/2 dilutions. PCS-EWT and SU exerted more potent cytotoxicity at 1/2 dilution than the other sealers.
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Takako YOSHIKAWA, Nipaporn WATTANAWONGPITAK, Eitetsu CHO, Junji TAGAMI
2012 年 31 巻 6 号 p.
1033-1038
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The aim of this study was to evaluate the effect of remaining dentin thickness (RDT) on resin composite bond strength to dentin surfaces when using various adhesive systems. One of three adhesives, Clearfil SE Bond, Single Bond or Clearfil Tri-S Bond, followed by Z100 resin composite were built up on flat dentin surfaces of human molars. The teeth were sectioned obtaining beams with crosssectional areas of approximately 1 mm
2. RDT was measured and microtensile bond strength was determined. Resulting data were categorized into four groups: RDT<2 mm; 2≤RDT<3 mm; 3≤RDT<4 mm; RDT≥4 mm. Clearfil SE Bond showed a correlation between µTBS and RDT. Single Bond showed no significant difference in µTBS for any RDT. The bond strength of resin composite to the different RDT flat dentin surfaces was affected by the adhesive system used.
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Sang-Hui YU, Yoon LEE, Seunghan OH, Hye-Won CHO, Yutaka ODA, Ji-Myung ...
2012 年 31 巻 6 号 p.
1039-1046
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The aim of this study was to evaluate the reinforcing effects of three types of fibers at various concentrations and in different combinations on flexural properties of denture base resin. Glass (GL), polyaromatic polyamide (PA) and ultra-high molecular weight polyethylene (PE) fibers were added to heat-polymerized denture base resin with volume concentrations of 2.6%, 5.3%, and 7.9%, respectively. In addition, hybrid fiber-reinforced composite (FRC) combined with either two or three types of fibers were fabricated. The flexural strength, modulus and toughness of each group were measured with a universal testing machine at a crosshead speed of 5 mm/min. In the single fiber-reinforced composite groups, the 5.3% GL and 7.9% GL had the highest flexural strength and modulus; 5.3% PE was had the highest toughness. Hybrid FRC such as GL/PE, which showed the highest toughness and the flexural strength, was considered to be useful in preventing denture fractures clinically.
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Satoshi YAMAGUCHI, Yuya YAMADA, Yoshinori YOSHIDA, Hiroshi NOBORIO, Sa ...
2012 年 31 巻 6 号 p.
1047-1053
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The virtual reality (VR) simulator is a useful tool to develop dental hand skill. However, VR simulations with reactions of patients have limited computational time to reproduce a face model. Our aim was to develop a patient face model that enables real-time collision detection and cutting operation by using stereolithography (STL) and deterministic finite automaton (DFA) data files. We evaluated dependence of computational cost and constructed the patient face model using the optimum condition for combining STL and DFA data files, and assessed the computational costs for operation in do-nothing, collision, cutting, and combination of collision and cutting. The face model was successfully constructed with low computational costs of 11.3, 18.3, 30.3, and 33.5 ms for do-nothing, collision, cutting, and collision and cutting, respectively. The patient face model could be useful for developing dental hand skill with VR.
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Ana Flávia Sanches BORGES, Juliete de Sousa SANTOS, Carla Müller RAMOS ...
2012 年 31 巻 6 号 p.
1054-1059
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The aim of this study was to compare the formation of marginal gaps after thermo-mechanical load cycling, between siloranebased and methacrylate-based restorations. Standardized class II cavities were made in 10 permanent human third molars that were restored with the adhesive system Clearfil SE Bond+composite Filtek Z-350 (Methacrylates) and with the composite bonding Filtek P90+P90 (Siloranes), respectively. After 24 h of storage in 100% humidity at 37°C, the restoration margins were stained, photographed, and evaluated. The gap length was calculated as the percentage of the total length of the margins. Thereafter, the specimens were tested by a thermo-mechanical machine and the marginal gap formation of the specimens was re-evaluated. The results were expressed as percentages of gaps and were submitted to a Mann Whitney test at 5% level of significance. Methacrylates showed a statistically significant higher percentage of gaps than Siloranes, both before and after cycling.
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Shinji TAKEMOTO, Akinori TASAKA, Masayuki HATTORI, Kaoru SAKURAI, Yuta ...
2012 年 31 巻 6 号 p.
1060-1067
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The objective of this study was to evaluate change in color in experimental titanium-20mass% chromium (Ti-20Cr) alloy in an oral environment. Pure Ti and Ti-6Al-7Nb and Co-29Cr-5Mo alloys, as references to compare change in color, were prepared by casting. The cast specimen was mirror-polished. Each specimen was affixed to a palatal plate and the plate then worn by a volunteer for up to 300 h. A few specimens showed a change in color. These changes and the median values among the tested alloys were not significant. Larger amounts of carbon, nitrogen, and oxygen were observed in the discolored alloys than in the slightly-discolored alloys. The spectra of the constituent elements of the alloys revealed no corrosion. In conclusion, the experimental Ti-20Cr alloys showed a level of resistance to change in color and corrosion similar to that in commercially available Ti and Co-29Cr-5Mo alloys.
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Binnaz HAZAR-YORUC, Andac Barkin BAVBEK, Mutlu ÖZCAN
2012 年 31 巻 6 号 p.
1068-1074
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
This study investigated the erosion kinetics of conventional and resin-modified glass-ionomer luting cements in acidic buffer solutions as a function of time. Disc shaped specimens were prepared from conventional (Ketac-Cem: KTC) and resin-modified glass ionomer cements (Fuji Plus: FP) and immersed in three acidic buffer solutions (0.01 M) namely, acetic acid/sodium acetate (AA
B), lactic acid/sodium lactate (LA
B) and citric acid/sodium citrate (CA
B) with a constant pH of 4.1 and stored for 1, 8, 24, 48, 80, 120 and 168 h. F concentration was determined using ion-specific electrode. Si, Ca and Al concentrations were determined by atomic absorption spectroscopy. Ca, Al, Si and F solubility rates in both FP and KTC were the highest in CA
B solution. The erosion rates of both FP and KTC in all buffer solutions increased as a function of immersion time. The amount of F eluted from FP was more than that of KTC. The total amount of elements released from FP was less than KTC in all solutions.
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Jiale FU, Feng PAN, Shinichi KAKUDA, Sharanbir K SIDHU, Takatsumi IKED ...
2012 年 31 巻 6 号 p.
1075-1081
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The purpose of this study was to evaluate the effect of air-blowing duration on the bonding performance of all-in-one systems using the same pressure (0.25 MPa). Three all-in-one systems were: EB (Easy Bond, 3M ESPE, USA), BB (BeautiBond, Shofu Inc., Japan) and GBp (G-Bond plus, GC Corporation, Japan). After adhesive application, the 3 systems were air-blown thereafter using 7 different durations (5 s, 10 s, 15 s, 20 s, 25 s, 30 s and 35 s). Bond strengths to dentin were determined using µTBS test after 24 h water storage. In addition, evaluation of both the resin-dentin interface and the fractured surface on the dentin side were performed by SEM. The maximum µTBS for each system, BB (40.4±14.8 MPa), EB (79.8±16.5 MPa), and GBp (47.3±17.6 MPa), were recorded with 15 s, 15 s and 25 s air-blowing duration respectively. Under the same air-pressure, the air-blowing duration could affect evaporation and the thickness of the adhesive layer, which contributed to the different bond strengths.
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Ayse ATAY, Vildan BOZOK CETINTAS, Ebru CAL, Buket KOSOVA, Atilla KESER ...
2012 年 31 巻 6 号 p.
1082-1086
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
The cytotoxicity of nine soft and hard lining materials (Mollosil Plus, Ufi Gel SC, Visco-gel, Molloplast-B, GC Tissue Conditioner, Vertex Rapid Simplified, GC Reline Hard, Vertex Self-Curing, Ufi Gel hard C) was evaluated using human gingival fibroblasts (HGFs). Twelve disk samples per lining material were prepared and incubated for 24, 48, 72, and 96 h. Cytotoxicity of each lining material's extract on cultured HGFs was measured using XTT assay. Data were analyzed using one-way ANOVA,
post hoc Dunnett's T3 and Bonferroni tests at a significance level of
p<0.05. At all incubation periods, all the hard lining materials (Vertex-SC, GC Reline Hard, Vertex-RS, and Ufi Gel hard C) showed cell viability higher than 90%. Among the soft lining materials, although there were no significant differences in cell viability among the different incubation periods for each lining material (
p>0.05), autopolymerized acrylic-based GC Tissue Conditioner showed significantly lower cell viability than the other soft lining materials at each incubation period. Among the hard lining materials, there were no significant differences both among the materials and across all incubation periods for each lining material (
p>0.05). In conclusion, all soft and hard liners exhibited good biocompatibility regardless of incubation time, except for GC Tissue Conditioner.
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Yoshinosuke HAMADA, Wataru FUJITANI, Naomasa KAWAGUCHI, Kiyoshi DAITO, ...
2012 年 31 巻 6 号 p.
1087-1096
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
In tissue engineering, biodegradable polymer materials with both high biocompatibility and high strength are very important as scaffolds for long term use. Therefore, in this research, we tried to prepare the three types of poly(L-lactic acid) (PLLA)/calcium phosphate (CP) hybrid composite for a scaffold biomaterial. The effects of addition of different CP on both biocompatibility and mechanical properties were evaluated. CP powders and voids were three-dimensionally and uniformly distributed in the solid samples and porous composite samples. These compositions of CP and PLLA greatly improved the cellular adhesiveness, which increased as the volume fraction of CP in the composite increased. For the porous samples, cells migrated into the pores. This study demonstrated that a composite of PLLA and CP is an effective new scaffold material that results in better osteoconductivity, bone regeneration, and mineralization and has moderately high strength.
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Reinhard GRUBER, Erik HEDBOM, Dieter D. BOSSHARDT, Roman HEUBERGER, Da ...
2012 年 31 巻 6 号 p.
1097-1102
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
There is a need for evaluating zirconia surface modifications and their potential impact on the biological response of osteogenic cells. Grit blasted zirconia discs were either left untreated or underwent acid or alkaline etching. Adhesion and osteogenic differentiation of MG63 cells was determined after one week of culture. The macro-scaled roughness of the grit blasted zirconia discs, independent of the surface treatment, was within a narrow range and only slightly smoother than titanium discs. However, the alkaline- and acid-etching led to an increase of the micro-roughness of the surface. The surface modifications had no effect on cell spreading and did not cause significant change in the expression of differentiation markers. Thus, in this respective setting, morphologic changes observed upon treatment of grit blasted zirconia discs with acid or alkaline do not translate into changes in MG63 cell adhesion or differentiation and are comparable to findings with anodized titanium discs.
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Taku KOYAMA, Toru SATO, Masao YOSHINARI
2012 年 31 巻 6 号 p.
1103-1110
発行日: 2012/11/30
公開日: 2012/12/01
ジャーナル
フリー
This study investigated the influence of surface roughness and cyclic loading on fatigue resistance in Y-TZP subjected to hot isostatic pressing (HIP). Fifty Y-TZP cylinders 3.0 mm in diameter were divided into Group A (polished by centerless method; TZP-CP) or Group B (blasted and acid-etched: TZP-SB150E). Twenty five cp-titanium cylinders (Ti-SB150E) were used as a control. Static and cyclic tests were carried out according to ISO 14801. The cyclic fatigue test was performed in distilled water at 37°C. Surface morphology and roughness as well as crystal phase on the surfaces were also evaluated. Fracture force under the static test was 1,765N (TZP-CP), 1,220N (TZP-SB150E), and 850 N (yield force, Ti-SB150E). Fracture values under the cyclic test decreased to approximately 70% of those under the static tests. These results indicate that HIPed Y-TZP with a 3.0-mm diameter has sufficient durability for application to dental implants.
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