Dental Materials Journal
Online ISSN : 1881-1361
Print ISSN : 0287-4547
ISSN-L : 0287-4547
Volume 32 , Issue 5
Showing 1-25 articles out of 25 articles from the selected issue
Original Paper
  • Takashi KIRIYAMA, Kenjiro KUROKI, Keisuke SASAKI, Masahumi TOMINO, Mas ...
    2013 Volume 32 Issue 5 Pages 679-687
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    A novel antibacterial polymer, coated with a silver-containing organic composite antibacterial agent, was dispersed in a self-cured acrylic resin. Residual viable cell count of each oral bacterial and fungal species cultivated on acrylic resin specimens containing the antibacterial polymer was significantly decreased when compared to those cultivated on specimens prepared from untreated polymer. A strong inverse correlation was found between the amount of eluted silver ions and the residual viable cell count of all species grown on the antibacterial polymer: the lower the viable cell count, the higher the amount of eluted silver ions. This clearly indicated the antibacterial activity of silver ions. As the content of organic composite antibacterial agent added to the polymer increased from 0.5% to 1.5% in 0.5% increments, amount of eluted silver ions significantly increased with each 0.5% increment to exert greater antibacterial effect.
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  • Sang-Kyu LEE, Tae-Wan KIM, Sung-Ae SON, Jeong-Kil PARK, Jong-Hwa KIM, ...
    2013 Volume 32 Issue 5 Pages 688-694
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    This study examined the effect of various light-curing units (LCUs) on the polymerization of low-shrinkage composite resins. Two different types of low-shrinkage composite resins (silorane-based and methacrylate-based) were light cured using a quartz-tungstenhalogen (QTH) (HX) unit, a single-peak light-emitting diode (LED) (DM) unit, and a dual-peak LED (GL) unit, respectively. Among the tested LCUs, HX showed the lowest light attenuation within the specimens. Among the specimens, Aelite LS and Venus Diamond showed the highest and lowest light attenuation, respectively. Silorane-based Filtek LS showed the highest degree of conversion both on the top and bottom surfaces. On the bottom surface, Grandio and Aelite LS showed the lowest (4.5–7.1%) and highest (25.0–40.0%) decrease in the degree of conversion compared to their top surface. For different LCUs, within the same resin product, the microhardness was significantly different. The silorane-based composite resin showed significantly less polymerization shrinkage than the methacrylate-based nanofiller-containing composite resins.
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  • Naho HAMANO, Satoshi INO, Takushi FUKUYAMA, Reinhard HICKEL, Karl-Hein ...
    2013 Volume 32 Issue 5 Pages 695-701
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    The purpose of our study was to evaluate the effects of surface treatment on the microtensile bond strength (MTBS) of silorane-based composites (Filtek Silorane, 3M ESPE) repaired with methacrylate-based composites (Ceram X, Dentsply). The MTBS were measured before or after thermo-mechanical fatigue simulation (FS). The surface conditioning regimes were: no treatment, bonding agent, silane, and silane+bonding agent. Before and after FS, no significant differences could be observed among the different pretreatment groups. FS did not change the MTBS although FS increased the repair strength of Silorane in our previous study under the same conditions, and after FS all of the failure modes showed adhesive failure, which means that the repair bond strengths between silorane-based composite and methacrylate-based composite were not durable. In conclusion, within the limitations of this study, with this composite neither bonding agent nor silane contributed to an increase in the tensile strength.
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  • Eiichiro OTSUKA, Akimasa TSUJIMOTO, Toshiki TAKAMIZAWA, Tetsuya FURUIC ...
    2013 Volume 32 Issue 5 Pages 702-708
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    The purpose of this study was to determine the influence of surface treatment of glass-ionomer (GIC) on bond strength of resin composite and surface free energies. Specimens were prepared and divided into three groups as follows: without pretreatment (control), phosphoric acid etching, and air-abrasion. Adhesive was applied and resin composite was bonded. For conventional GIC, acid etching or air-abrasion increased bond strength (8.5–8.8 MPa) when compared with controls (4.7 MPa); however, RMGIC resulted in significantly lower bond strengths (10.3–15.8 MPa) than in controls (14.2–20.5 MPa). The value of the γS component increased when conventional GIC was treated with phosphoric acid or air-abrasion (60.1–60.5 mJ•m−2) when compared with controls (52.8 mJ•m–2).These results indicate that surface treatment of conventional GIC promoted higher bond strength to resin composite and higher Lewis-base components, but decreased bond strength for RMGIC.
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  • Kyunghwan KIM, Kyung Mi SON, Ji Hyun KWON, Bum-Soon LIM, Hyeong-Cheol ...
    2013 Volume 32 Issue 5 Pages 709-717
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    During restoration of damaged teeth in dental clinics, dentin bonding agents are usually overlaid with restorative resin composites. The purpose of this study was to investigate the effects of restorative resin composites on cytotoxicity of dentin bonding agents. Dentin bonding agents were placed on glass discs, pre-cured and uncured resin composite discs. Bonding agents on the glass discs and composite resins discs were light cured and used for agar overlay cytotoxicity testing. Dentin bonding agents on composite resin discs exhibited far less cytotoxicity than that on glass discs. The polymerization of resin composite increased the surface hardness and decreased the cytotoxicity of bonding agents. In conclusion, composite resins in dental restorations are expected to enhance the polymerization of dentin bonding agents and reduce the elution of resin monomers, resulting in the decrease of cytotoxicity.
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  • Yoji INABA, Fumio TERAOKA, Masafumi NAKAGAWA, Satoshi IMAZATO
    2013 Volume 32 Issue 5 Pages 718-724
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    We have developed a new direct construction method for core build-up starting with the hypothesis that an improvement in pullout strength and a decrease in the number of voids in the restorative material will become possible by filling a hollow fiber reinforced post with the restorative material from the bottom of the root canal. For the pullout test, the hollow post was fixed to the head of a mixing tip and inserted into the bottom of a cylinder. The restorative material was then injected through the hollow post. The pullout load of the hollow posts was significantly higher than that of the solid fiber posts. The number of voids observed in the restorative material when using the hollow post was about 1/5 of that in the case of the solid post.
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  • Masanori HASHIMOTO, Hirokazu TOSHIMA, Tetsu YONEZAWA, Koji KAWAI, Taka ...
    2013 Volume 32 Issue 5 Pages 725-733
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    With the continuous progress in nanomaterial development for biomedicine, the potential cytotoxicity of nanoparticles is drawing more attention and concern for clinical applications. The purpose of this study was to evaluate biological responses of new waterdispersible silver nanoparticles (Ag-NPs) stabilized by Ag-C σ-bonds in cultured murine macrophages (RAW264.7) and osteoblastlike cells (MC3T3-E1) using cell viability and morphological analyses. For RAW264.7, Ag-NPs seemed to induce cytotoxicity that was dependent on the Ag-NP concentration. However, no cytotoxic effects were observed in the MC3T3-E1 cell line. In microscopic analysis, Ag-NPs were taken up by MC3T3-E1 cells with only minor cell morphological changes, in contrast to RAW264.7 cells, in which particles aggregated in the cytoplasm and vesicles. The ability of endocytosis of macrophages may induce harmful effects due to expansion of cell vesicles compared to osteoblast-like cells with their lower uptake of Ag-NPs.
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  • Naoya MATSUMOTO, Masao YOSHINARI, Shinji TAKEMOTO, Masayuki HATTORI, E ...
    2013 Volume 32 Issue 5 Pages 734-743
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    The purpose of the present study was to investigate the influence of the intermediate ceramics and firing temperature on bond strength between tetragonal zirconia polycrystal (TZP) and its intermediate ceramics. Two types of intermediate ceramics, defined as a ceramics placed between the TZP and its veneering ceramics, were used; one including high-strength lithium-disilicate (EP) or feldspathic liner porcelain (SB). The firing temperature of the intermediate ceramics was set at 930°C, 945°C or 960°C. Shear bond strength showed values of 35.8 MPa in SB and 54.9 MPa in EP at a firing temperature of 960°C. Electron probe microanalysis revealed that components of the intermediate ceramics remained on the TZP surface after debonding, indicating that fractures occurred in the intermediate ceramics near the TZP. These results indicate that the bond strength between and a TZP framework and its veneering ceramics could be improved by using a high-strength intermediate ceramics and a comparatively high firing temperature.
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  • Kazuhiro YOSHIDA, Tadafumi KUROGI, Tetsurou TORISU, Ikuya WATANABE, Hi ...
    2013 Volume 32 Issue 5 Pages 744-752
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    This study evaluated the effects of the fluorinated monomer of 2,2,2-trifluoroethyl methacrylate (TFEMA) on the properties of autopolymerized hard direct denture reline resins. Iso-butyl methacrylate (i-BMA) and 2-hydroxyethyl methacrylate (2-HEMA) containing 30% TFEMA by weight were used as monomers, while poly(ethyl methacrylate) was used as a powder. Setting characteristics, dynamic mechanical properties, and changes over time, as well as wettability were determined by use of an oscillating rheometer, dynamic viscoelastometer, and contact angle meter. Water absorption and solubility were also measured according to ISO specifications. The reline resin based on i-BMA had greater elasticity and stiffness properties, while that based on 2-HEMA showed fewer dynamic mechanical property changes over time with the addition of TFEMA. Furthermore, water absorption and solubility tended to be reduced and contact angle increased. The results of this study suggest that TFEMA improves mechanical properties and durability of reline resins over time.
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  • Masahiko MINAMI, Masaaki TAKECHI, Kouji OHTA, Akira OHTA, Yoshiaki NIN ...
    2013 Volume 32 Issue 5 Pages 753-760
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    The aim of the present study was to examine whether interconnected porous hydroxyapatite ceramics (IP-CHA) could be used as bone substitute for implant treatment in reconstructive surgery. We firstly assessed if surround of the titanium surface placed into granular or block-type IP-CHA can observe new bone formation in a rabbit bone defect model. Subsequently, osseointegration and stability of titanium implant inserted into block-type IP-CHA was investigated in a rabbit onlay graft model. Direct contact between new bone and the surface of the titanium in granular- or block-type IP-CHA was found in a rabbit bone defect. Further, new bone formation was found in direct contact with the implant surface in the block-type IP-CHA in an onlay graft model, and the implant stability quotient (ISQ) values were significantly increased after surgery. Therefore, IP-CHA may be a useful material for implant treatment in reconstructive surgery strategies.
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  • Wei WANG, Yuhe ZHU, Jiajia LI, Susan LIAO, Hongjun AI
    2013 Volume 32 Issue 5 Pages 761-766
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    This study investigated the efficacy of cold light bleaching using different bleaching times and the effects thereof on tooth enamel. Before and after bleaching, stained tooth specimens were subjected to visual and instrumental colorimetric assessments using Vita Shade Guide and spectrophotometric shade matching. Enamel surface alterations were examined using scanning electron microscopy (SEM) to analyze surface morphology, surface microhardness (SMH) measurement to determine changes in mechanical properties, and X-ray diffraction (XRD) to characterize post-bleaching enamel composition. Cold light bleaching successfully improved tooth color, with optimal efficacy when bleaching time was beyond 10 min. Significant differences in surface morphology were observed among the different bleaching times, but no significant differences were observed for enamel composition and surface microhardness among the different bleaching times. Results of this study revealed an association between the bleaching time of cold light bleaching and its whitening efficacy. Together with the results on enamel surface changes, this study provided positive evidence to support cold light bleaching as an in-office bleaching treatment.
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  • Leila DANESHMEHR, Fusun OZER, Francis K. MANTE, Markus B. BLATZ
    2013 Volume 32 Issue 5 Pages 767-774
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    The purpose was to evaluate the effect of air-blowing duration of three different adhesive systems on immediate or thermal aged resin-dentin shear bond strength (SBS). Human dentin surfaces were bonded with: one-step (Bond Force, BF), two-step (FL-Bond II, FLB) and three-step (Scotch Bond Multi-Purpose, SBMP) adhesive systems. Bonded surfaces from each group were air-blown for 0, 5, or 10 s and cured. Composite cylinders were built on the treated surfaces and cured. Half of the specimens from each group were tested immediately and the other halves were tested after thermal aging. Statistical analysis showed significant decrease in SBS after thermal aging compared to immediate testing in all groups, except BF after 5 s air-blowing or FLB and SBMP with no air-blowing (p>0.05). The results suggested that 5 s air-blowing is necessary to obtain a stable SBS for BF. However, extended airblowing duration of FLB and SBMP decreased the SBS significantly after thermal aging.
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  • Masahiro IIJIMA, Masanori HASHIMOTO, Naohisa KOHDA, Susumu NAKAGAKI, T ...
    2013 Volume 32 Issue 5 Pages 775-780
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    In this work, a bioactive glass was deposited on the alumina disk specimens by radio-frequency magnetron sputtering to study crystal formation ability in artificial saliva. Bioactive glass-coated specimens were immersed in artificial saliva for 1 week and 6 months. The specimens were observed with a scanning electron microscope (SEM) and the composition was determined by energy dispersive spectroscopy (EDS). The crystals that formed on the specimens were analyzed by Raman spectroscopic analysis and Micro-X-ray diffraction. SEM photomicrographs showed the formation of needle-like structures after immersion for 1 week, and tabular structures formed on the surface of the specimen for 6 months. EDS showed that both the needle-like and tabular structures were enriched with Ca and P. Raman and Micro-XRD spectra for the tabular structure showed peaks that may correspond to calcium phosphate. Thus, when immersed in artificial saliva, bioactive glass-coated alumina produced a crystal which might be calcium phosphate.
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  • Pornpot JIANGKONGKHO, Krid KAMONKHANTIKUL, Hidekazu TAKAHASHI, Mansuan ...
    2013 Volume 32 Issue 5 Pages 781-786
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    This study investigated the effect of fiber reinforced composite resin (FRC) post lengths, ferrule, and full coverage metal crown onfracture resistance of endodontically treated teeth (ETT) using an experimental FRC post with the similar elastic modulus of dentin (11.5 GPa). ETT was restored according to 1 of 7 combinations of FRC post length (10, 5, 2.5, 0 mm), ferrule (0, 2 mm), and with/without metal crown (n=6). An oblique compressive load was applied on the restored teeth using a universal testing machine. Fracture loads were evaluated with 1-way ANOVA and Tukey HSD test (p<0.05). Compared with tooth preparation only, the fracture loads of ETT restored with composite resin and different post lengths were not significantly different. The group with the ferrule with metal crown showed significantly greater fracture resistance than the others.
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  • Andreas ZENTHÖFER, Peter RAMMELSBERG, Clemens SCHMITT, Brigitte OHLMAN ...
    2013 Volume 32 Issue 5 Pages 787-792
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    To compare differences between the wear behavior of two types of metal-free resin composite crown with a control after three years in clinical service. Sixty-six participants needing one to three posterior single crowns were fitted with 120 crowns. Abutment teeth were randomly assigned to three groups: 40 resin composite crowns with fiber-reinforced framework, 40 resin composite crowns without fiber-reinforced framework, and 40 metal-ceramic crowns. To assess wear, gypsum replicas of the crowns were fabricated and scanned with a 3D laser scanner at baseline and after three years. Differences between the groups were analyzed by use of mixedeffects regression models. Wear of resin composite crowns with fiber-reinforced framework (p=0.0043) and resin composite crowns without framework (p=0.0246) was significantly greater than in the metal-ceramic group. Wear of metal-free resin composite crowns after three years was significantly greater than that of metal-ceramic crowns, but the wear was still clinically acceptable.
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  • Soichi KURODA, Akikazu SHINYA, Daiichiro YOKOYAMA, Harunori GOMI, Akiy ...
    2013 Volume 32 Issue 5 Pages 793-800
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    The effects of coloring agents (Vita in-ceram 2000 YZ coloring liquid (VL) and IPS e.max ZirCAD (IS)) and shades (1, 3, and 5) applied during sintering on the bending strength and fracture toughness of zirconia ceramics was examined. No differences in the bending strength or fracture toughness were observed for the type of coloring agent used. Moreover, the bending strength and Vickers hardness of the zirconia ceramics decreased, while the crack length and fracture toughness did not change with the different coloring agents. The marginal borders of the indentations formed were clear and linear, and no damage, including chipping, was observed. Therefore, clinical application of zirconia ceramics can be recommended because the coloring agents and shades applied during sintering have the same effect as an opaque layer and cause no significant deterioration of the mechanical properties of the zirconia ceramics.
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  • Rifat GOZNELI, Coskun YILDIZ, Burcin VANLIOGLU, Buket Akalin EVREN, Ya ...
    2013 Volume 32 Issue 5 Pages 801-807
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    The aims of this study were to investigate the retention force changes of different attachment systems after 10,000 insertion-separation cycles and the difference in retention force between precious and non-precious materials of the same attachment system. Four types of attachments (Ball, Rod, M3 stud, and AP-Piccolino), produced using both precious and non-precious metal alloys, were tested (n=6). Data were analyzed using analysis of variance (ANOVA), Tukey’s multiple comparison test, and t-test at a significance level of p≤0.05. Retention forces of all attachment types were significantly decreased after 10,000 insertion-separation cycles (p≤0.05). Rod and M3 attachment systems showed an initial increase in retention force, then an eventual decrease. At the end of the test, precious types of M3 and AP-Piccolino attachments had significantly higher retention force values than their non-precious ones (p≤0.05). Friction between non-precious attachment parts resulted in a higher retention loss than precious metal alloys.
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  • Qiu LI, Andrew D. DEACON, Nichola J. COLEMAN
    2013 Volume 32 Issue 5 Pages 808-815
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    Zirconium oxide (ZrO2) has been nominated as a radiopacifying agent for use in MTA-like Portland cement-based root-filling materials. This research examines the impact of 20 wt% ZrO2 nanoparticles in the size range 50 to 75 nm on the early hydration chemistry of white Portland cement. Nano-ZrO2 was found to accelerate the degree of hydration by 26% within the first 24 h by presenting efficient nucleation sites for the precipitation and growth of the early C-S-H gel products. The presence of nano-ZrO2 was also found to divert the fate of the aluminium-bearing reaction products by lowering the ettringite to monosulphate ratio, reducing the size of the ettringite crystals and by increasing the Al:Si ratio of the C-S-H gel phase. The chemical and microstructural changes conferred upon the cement matrix by the nano-ZrO2 particles had a positive impact on in vitro biocompatibility with respect to MG63 osteosarcoma cells (via MTT assay).
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  • Nicola MOBILIO, Bruna BORELLI, Roberto SORRENTINO, Santo CATAPANO
    2013 Volume 32 Issue 5 Pages 816-821
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    This study evaluated the combined influence of horizontal bone loss and post length on the fracture resistance of endodontically treated teeth (ETT). Twenty premolars were endodontically treated and divided into four groups of two different post insertion depths (5 and 7 mm) and two alveolar bone levels from cement-enamel junction (2 and 5 mm). After posts (RelyX Fiber Post) were cemented using a self-adhesive resin cement (RelyX Unicem Aplicap) and cores were built up (Filtek Supreme XT Universal Restorative, 3M ESPE, USA), cobalt-chrome copings were luted to each prepared tooth. All specimens were subjected to thermocycling and mechanical loading until fracture occurred. Mean fracture loads (N) were 1,445±342.2 (2 mm bone level/5 mm depth), 1,516±413.4 (2 mm bone level/7 mm depth), 1,736.4±1113.8 (5 mm bone level/5 mm depth), 1,038.6±600.2 (5 mm bone level/7 mm depth). No significant differences were found. Therefore, bone level and post length did not seem to influence the fracture resistance of ETT.
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  • Yusuke YAMANAKA, Yoshimi SHIGETANI, Kunihiko YOSHIBA, Tomoatsu KANEKO, ...
    2013 Volume 32 Issue 5 Pages 822-827
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    Major histocompatibility complex (MHC) class II molecule-expressing cells and macrophages play a pivotal role in mediating the host tissue response to biomaterials. This study investigated the responses of these cells to epoxy resin-based and 4-META-containing, methacrylate resin-based endodontic sealers (AH Plus and MetaSEAL respectively) in rat connective tissue. Silicone tubes loaded with one of the sealers or solid silicone rods (control) were subcutaneously implanted in male Wistar rats for three time periods of 7, 14, or 28 days. Tissue specimens were immunoperoxidase-stained for MHC class II molecules and CD68 (a general macrophage marker). Results showed that AH Plus-implanted tissue displayed significantly more MHC class II-positive cells than the control at 14 and 28 days, whereas MetaSEAL-implanted tissue showed significantly more CD68-positive cells than both AH Plus-implanted tissue and the control at all time periods. It was concluded that the epoxy resin-based sealer induced the infiltration of MHC class II molecule-expressing cells, whereas 4-META-containing, methacrylate resin-based sealer elicited macrophage infiltration.
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  • Maho SHIOZAWA, Hidekazu TAKAHASHI, Naohiko IWASAKI, Motohiro UO
    2013 Volume 32 Issue 5 Pages 828-833
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    The objective of this study was to evaluate the effect of the concentration of calcium chloride (CaCl2) solution on the surface hardness of restorative glass ionomer cements (GICs). Two high-viscosity GICs, Fuji IX GP and GlasIonomer FX-II, were immersed in several concentrations of CaCl2 solution for 1 day and 1 week. The immersed specimen surfaces were evaluated using microhardness testing, grazing incidence X-ray diffraction, and energy-dispersive X-ray spectroscopy. Immersion in a higher concentration of CaCl2 solution produced a greater increase in the surface hardness. No crystalline substance was observed on the immersed surface. Calcium ions were selectively absorbed in the matrix of the GIC surface after immersion. They reacted with the non-reacted carboxylic acid groups remaining in the cement matrix. These reactions were considered to cause an increase in the surface hardness of the GICs.
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  • Tissiana BORTOLOTTO, Davy GUILLARME, Daniel GUTEMBERG, Jean-Luc VEUTHE ...
    2013 Volume 32 Issue 5 Pages 834-838
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    The aim of this study was to evaluate relationship between shrinkage development and early solubility of two commonly used luting materials, a self-adhesive cement (GCem chemical and light cured) and composite resin (Tetric). Linear displacement, shrinkage forces and leaching of UDMA from specimens immersed in 75% ethanol/25% water were measured. The least amount of linear shrinkage (33.0±2.9 µm) and polymerization force (4.1±0.3 kg) was observed in Tetric. UDMA leaching (% µg/mL) was the following: chemically cured GCem (4.2±0.2)>light cured GCem (1.5±0.1)>Tetric (0.1). Shrinkage development in the early stages of polymerization was much slower in the self-cured specimens in respect to light cured ones. With the chemically cured self-adhesive cement, incomplete materials’ setting during the initial stages after polymerization favored monomer leaching from the cements’ mass.
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  • Yuichi TERUI, Kotaro SATO, Daisuke GOTO, Yasuhiro HOTTA, Yukimichi TAM ...
    2013 Volume 32 Issue 5 Pages 839-846
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    The aim of this study was to examine the compatibility of Ce-TZP/Al2O3 nanocomposite (CTA) frameworks and veneering porcelains using the Schwickerath crack initiation test and clarify the effects on debonding/crack initiation strength (DIS) of both surface pretreatment (include heat treatment) of the frameworks, type of veneering porcelain varying the coefficient of thermal expansion (CTE), and surface roughness of the frameworks. The surfaces of Ce-TZP/Al2O3 plates were mechanically treated and followed by post-heat treatment. The liner and body porcelains were built up and fired according to the manufacturer’s instructions. Surface analyses of the fractured plates showed compatibility with liner porcelains. Since no statistically difference in the DIS was found amongst the different surface treatments, post-heat treatments don’t be mandatory. Whereas, since differences in DIS were found when different porcelains with different CTE were used, we concluded the matching of CTE of the porcelain with that of Ce-TZP/Al2O3 was important for successful all-ceramic restorations using Ce-TZP/Al2O3 frameworks.
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  • Satoshi YAMAGUCHI, Yoshinori YOSHIDA, Hiroshi NOBORIO, Shinya MURAKAMI ...
    2013 Volume 32 Issue 5 Pages 847-852
    Published: August 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    Our aim was to evaluate haptic virtual reality (VR) simulation with repetitive training as a tool in teaching caries removal (CR) and periodontal pocket probing (PPP) skills. For the CR simulation, multilayered virtual models composed of tooth substance, caries, and pulp were developed. Seven students completed three training sessions each, which were scored based on the volume of the cut region, the number of instances of handpiece overload, and total cutting time. For the PPP task, we developed a virtual periodontal disease model and 26 students received training in measuring pocket depth. Pocket probing force was measured and proficiency was evaluated. In the CR task, scores for the second and third training sessions were significantly higher than for the first training session. We likewise obtained effective repetitive training results for the PPP task. Our simulator was effective at teaching hand skills for both tasks within short-term evaluation.
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  • Mirko SOLDO, Paris SIMEON, Jurica MATIJEVIĆ, Domagoj GLAVINA, Davor IL ...
    2013 Volume 32 Issue 5 Pages 853-858
    Published: September 30, 2013
    Released: October 01, 2013
    JOURNALS FREE ACCESS
    The aim of this study was to compare the microleakage of class V cavities restored by silorane resin with those restored by the methacrylate resin system. Sixty standardized class V cavities were prepared on premolars. The teeth were restored with FiltekTM Silorane and SiloraneTM System Adhesive, FiltekTM Silorane and AdperTM Easy One and FiltekTM Supreme XT and AdperTM Easy One. The area and the depth of dye leakage were measured. Considering dye leakage area, the best results were achieved in group I (mean-M=0.114±0.083 mm2), then in group III (M=0.384±0.480 mm2) and finally in group II (M=5.389±6.587 mm2). Considering the depth of dye leakage, there was a significant difference between group I (mean rank-m.r.=1.23±0.44 mm) and II (1.98±0.83 mm), group II and III (1.23±0.40 mm). In this study silorane composite and its adhesive showed less microleakage than the methacrylate composite, and it showed compatibility only with its assigned adhesive. Clinical Significance: Less microleakage of silorane restorations could provide better and long lasting composite fillings.
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