Dental Materials Journal
Online ISSN : 1881-1361
Print ISSN : 0287-4547
ISSN-L : 0287-4547
Advance online publication
Showing 1-50 articles out of 83 articles from Advance online publication
  • Yuri AKIYAMA, Fuminori IWASA, Yasuhiro HOTTA, Takashi MATSUMOTO, Yoko ...
    Type: research-article
    Article ID: 2019-435
    Published: 2020
    [Advance publication] Released: December 02, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    We evaluated the biological effects of implant abutments made from ceria-stabilized zirconia/alumina nanocomposite (Ce-TZP/Al2O3) with surface roughness variations using human gingival fibroblasts (HGF-1) in the transmucosal region. Two types of titanium (Ti) and Ce-TZP/Al2O3 disks with different surface roughness profiles were prepared (Ra0.9 and Ra0.02). Surface properties were evaluated using SEM, EDX, and wettability analysis. Biological parameters including cell adhesion, proliferation and morphology, collagen deposition, and inflammatory cytokine expression were evaluated for each disk. Surface morphology analysis of Ce-TZP/Al2O3 and Ti elucidated the uniform linear structures of Ra0.9 and the smooth and flat structures of Ra0.02. Cell morphology showed spindle-shaped and large, circular forms, respectively. Cell adhesion and proliferation and collagen deposition were significantly increased on Ce-TZP/Al2O3 Ra0.02 disk compared with the others, with no significant differences in cytokine expression among all the disks. The reduced surface roughness of Ce-TZP/Al2O3 was advantageous for promoting biological effects in the transmucosal region.

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  • Gülbike DEMİREL, Ayşe Işıl ORHAN, Özgür IRMAK, Fulya AYDIN, Arda BUYUK ...
    Type: research-article
    Article ID: 2020-071
    Published: 2020
    [Advance publication] Released: December 02, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The aim of this study was to compare the effects of conventional, sonic or pre-heating insertion techniques on internal void formation of bulk-fill composites with micro-computed tomography. Standardized cylindrical cavities were prepared in 160 human third molars. Four groups received different paste-like bulk-fill composites: SonicFill 2 (SF2); VisCalor Bulk (VCB); Filtek One Bulk-fill restorative (FBF); Tetric EvoCeram Bulk Fill (TEB); and a conventional posterior composite, Clearfil Majesty Posterior (CMP). A hybrid CAD/CAM block was selected as a control (n=10). Composite restorations were built according to each resin composite type and insertion technique (n=10). Micro-CT was used to assess internal void rates. Data was analyzed with two-way ANOVA and Tukey’s multiple comparisons test (α=0.05). CAD/CAM blocks were free of voids. For each composite, the highest void rates were observed for the sonic delivery method (p<0.05) except for SF2. SF2 was not affected by insertion techniques (p>0.05). Other composites showed the lowest void rates with pre-heating technique.

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  • Woraporn HOMSIANG, Krid KAMONKHANTIKUL, Mansuang ARKSORNNUKIT, Hidekaz ...
    Type: research-article
    Article ID: 2020-095
    Published: 2020
    [Advance publication] Released: December 02, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    This study evaluated the antifungal, physical, and mechanical properties of tissue conditioner incorporated with different amounts of zinc oxide nanoparticles (ZnOnps) at different storage times (0, 7, and 14 days). Specimens of 0, 5, 10, 15 wt% ZnOnps, or 15 wt% nystatin incorporated into tissue conditioner were fabricated (control, 5Zn, 10Zn, 15Zn, and Nys). The direct contact test (n=6) was performed to evaluate the antifungal effect against C. albicans suspension. The penetration depth (n=6) and tensile bond strength (n=8) were evaluated following ISO 13139. The 15Zn significantly reduced C. albicans cell number compared with control at all storage times (p<0.001). The penetration depths and tensile bond strengths of the 5Zn, 10Zn, 15Zn, and Nys were not significantly different compared with control at all storage times (p>0.05). In conclusion, the 15Zn provides antifungal effect up to 14 days without adverse effects on penetration depth and tensile bond strength.

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  • Bogna STAWARCZYK, Michael BRAUNEIS, Benedikt LANGWIEDER, Sebastian SPI ...
    Type: research-article
    Article ID: 2019-307
    Published: 2020
    [Advance publication] Released: November 19, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    This study tested and compared properties of six modern indirect veneering resin composites (VRC), namely Ceramage (Shofu), dialog Vario (Schütz Dental), Gradia Plus (GC Europe), in:joy (Dentsply), Signum composite (Heraeus Kulzer), and SR Nexco (Ivoclar Vivadent). Specimens were fabricated from dentin and enamel pastes and following properties were analyzed: (1) two-body wear (TB), (2) surface roughness (SR), (3) Martens hardness parameters (HM and EIT), and (4) translucency (T). The highest impact on HM and EIT was exerted by VRC brand (HM: ηP2=0.960/ EIT: ηP2=0.968; p<0.001), followed by VRC paste material (HM: ηP2=0.502/ EIT: ηP2=0.580; p<0.001), and aging duration (HM: ηP2=0.157/ EIT: ηP2=0.112; p<0.001). Lowest and highest TB were measured for Signum composite and dialog Vario, respectively (p<0.001). Highest T was showed Signum composite and Ceramage (p<0.001). VRCs should be individually selected with respect to the indication area, due to different surface properties.

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  • Haruka TAKESUE YANO, Hiroshi IKEDA, Yuki NAGAMATSU, Chihiro MASAKI, Ry ...
    Type: research-article
    Article ID: 2020-023
    Published: 2020
    [Advance publication] Released: November 19, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The purpose of this study is to clarify physical and chemical changes in surfaces of CAD/CAM composites caused by alumina airborne-particle abrasion and its effect on adhesive bonding. Our study involved three dispersed filler (DF)-based and a polymer-infiltrated ceramic network (PICN)-based CAD/CAM composites. Changes in the surface morphologies of the composites were examined, and surface free energy (SFE) analysis was performed based on Owens-Wendt theory. The influence of the abrasion on the bond strengths of CAD/CAM composites to the resin cement was characterized by shear bond strength (SBS) test. The abrasion increased the roughness of the composites. The SFE analysis showed that the abrasion significantly increased the dispersive component but decreased the polar component of the SFE associated with the DF-based composites, while no change occurred for those of the PICN-based composite. The abrasion slightly improved the SBSs for the DF-based composites but not that of the PICN-based composite.

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  • Vasavat SOONTORNVATIN, Taweesak PRASANSUTTIPORN, Ornnicha THANATVARAKO ...
    Type: research-article
    Article ID: 2020-025
    Published: 2020
    [Advance publication] Released: November 19, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    This study aimed to evaluate the effect of silane coupling agent contamination on the microtensile bond strength (µTBS) of 3-step etch-and-rinse adhesives on dentin. Flat occlusal dentin surfaces were prepared and randomly divided into 8 groups (n=20) based on the tested adhesives; Scotchbond Multi-purpose or Optibond FL, with contamination of an experimental silane (2 vol% of 3-m ethacryloxypropyltrimethoxysilane at pH 4.5) before acid-etching, after-etching or after-priming; while the groups without silane contamination served as controls. µTBS data were analyzed by two-way ANOVA and Tukey’s HSD tests at a significance level of 0.05. Additional specimens of contaminated dentin were used to analyze changes in the organic molecules by Fourier transform infrared spectroscopy (FTIR). Silane contamination before acid-etching did not significantly change µTBS (p>0.05), but contamination after-etching and after-priming significantly decreased µTBS of both adhesives (p<0.05). Silane contamination had an adverse effect on the dentin bond strength of 3-step etch-and-rinse adhesives especially after-priming.

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  • Marco SALERNO, Francesca VIZZA, Andrea AMAROLI, Antonio SIGNORE, Angel ...
    Type: research-article
    Article ID: 2020-066
    Published: 2020
    [Advance publication] Released: November 19, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    We considered Class II dental cavities in critical tooth areas concerned with vital pulp therapy, and evaluated the marginal gap after treatment with Biodentine and Geristore, and one composite after either etching and adhesive (V2) and after use of a self-etching system (iBond Universal). We measured the surface morphology at the marginal gap by optical profilometry, and carried out analysis of the 3D data according to a new effective definition of marginal gap. The defined quantity was assessed for statistical significance of the apparent differences. The largest gaps appeared for Geristore (first) and Biodentine (not significantly lower), whereas the gaps of the composite controls were both lower, the lowest being the two-step self-etched system with respect to the three-steps etched and adhesive system, yet without statistical significance. Obviously, there is still room for improvement of the vital pulp therapy restorative materials, as compared to the use of standard composite systems.

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  • Imran FAROOQ, Abdul Samad KHAN, Imran Alam MOHEET, Emad ALSHWAIMI
    Type: research-article
    Article ID: 2020-078
    Published: 2020
    [Advance publication] Released: November 19, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The aim was to synthesize a toothpaste and analyze its effect on surface micro-hardness and roughness of enamel. Basic paste was prepared by using basic ingredients. Theobromine (0.2 wt%) and laboratory synthesized fluoridated-bioactive glass (F-BG, 4 wt%) were added to it. Post-demineralization, 36 enamel blocks were divided into six groups that were brushed with their respective toothpaste+artificial saliva (AS): group 1 (control): basic paste; group 2: basic paste+theobromine; group 3: commercial theobromine toothpaste; group 4: commercial BG toothpaste; group 5: basic paste+F-BG; and group 6: basic paste+theobromine+F-BG. On micro-hardness analysis, group 6 performed best, followed by group 4. Surface roughness results showed the maximum decrease in roughness values for group 6, followed by group 5. Treatment with toothpaste composition containing theobromine+F-BG resulted in the enamel’s increased micro-hardness and decreased surface roughness.

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  • Toru SHIIYA, Aiko KATAOKA, Kiyoshi TOMIYAMA, Fukue FUJINO, Yoshiharu M ...
    Type: research-article
    Article ID: 2019-396
    Published: 2020
    [Advance publication] Released: November 11, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    This study investigated the anti-demineralization effects of surface pre-reacted glass-ionomer (S-PRG) filler-containing varnishes. Thirty-five bovine root specimens were divided into five treatment groups, with seven specimens each coated with 1) MI varnish (MIV), 2) F varnish (FV), 3) PRG varnish I (PV), 4) PRG varnish II (with sodium fluoride added, PVF), and 5) acid-resistant nail varnish (Control). A 3×1 mm area of the dentin surface adjacent to each varnish was demineralized for one week at 37°C. Integrated mineral loss (IML) of these lesions was determined by transverse microradiography, as was the amount of fluoride released by each material. IML was significantly lower in the PV and PVF groups than in the Control group, and was significantly lower in the PVF than in the MIV and FV groups. These findings indicated that S-PRG filler-containing varnishes, especially varnish containing sodium fluoride, had superior anti-demineralization effects on root dentin.

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  • Beibei LI, Tao YANG, Rongxin SUN, Pan MA
    Type: research-article
    Article ID: 2020-034
    Published: 2020
    [Advance publication] Released: November 11, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The aim of this study was to assess the biological and antibacterial properties of composite coatings on titanium surfaces modified by microarc oxidation and sol-gel processing. A layer of hydroxyapatite (HA) with different concentrations of zinc (Zn) ions, prepared by the sol-gel method, was coated on microarc oxidized Ti (MAO-Ti) substrates. Five groups of specimens were tested. The microstructures, elemental compositions, and chemical phases of the composite coatings were investigated, and the biological and antibacterial properties of specimens were evaluated in vitro. The EDS and XRD results confirmed the composite coatings contained HA and Zn ions which was formed on titanium surfaces. The proliferation and ALP activity of BMSCs was significantly higher in group MAO-Ti+HA and MAO-Ti+HA+Zn(High), but MAO-Ti+HA+Zn(High) showed better antibacterial performance. The MAO-Ti substrate coated with the higher Zn concentration in the HA coating exhibited not only favorable biocompatibility, but also antibacterial action against Gram-negative anaerobic bacteria.

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  • Koki INATOMI, Hisae SAITO, Toshiya ENDO
    Type: research-article
    Article ID: 2020-113
    Published: 2020
    [Advance publication] Released: November 11, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The aim of this study was to assess the effects of three adhesives with different viscosities and an adhesion promoter on the shear bond strength (SBS) of orthodontic brackets bonded to human premolars with an indirect bonding system (IDBS). High, medium and low viscosity IDBSs with and without application of the adhesion promoter were used. The mean SBSs of the high and low viscosity IDBSs were significantly higher than that of the medium viscosity IDBS. Application of the adhesion promoter significantly increased the SBSs. The adhesion promoter significantly increased the surface roughness and free-energy of enamel. Irrespective of application or nonapplication of the adhesion promoter, the high and low viscosity IDBSs are effective for bracket bonding. Use of the medium viscosity IDBS in combination with the adhesion promoter is recommended for obtaining a clinically acceptable SBS.

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  • Samah SAKER, Mutlu ÖZCAN
    Type: research-article
    Article ID: 2020-007
    Published: 2020
    [Advance publication] Released: November 07, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    To investigate and analyze the impact of teeth preparation designs and sintering protocol on marginal fit and fracture resistance of monolithic translucent zirconia laminate veneers. A total of 40 extracted intact human maxillary central incisors were assigned into 4 groups (n=10/each group) to investigate 2 variables: (1) the design of tooth preparation (a 1.5 mm incisal reduction with or without palatal chamfer) and (2) the two different sintering programs used for translucent zirconia restoration (standard or speed sintering procedure). Marginal discrepancy was evaluated using a digital microscope. The specimens were loaded to failure in the compression mode, using a universal testing machine with a crosshead speed of 0.5 mm/min. Marginal adaptation of monolithic translucent zirconia laminates are affected by both tooth preparation design and sintering protocol. However, resistance to fracture of translucent zirconia laminates has affected mainly by sintering procedure regardless the teeth preparation design used.

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  • Ahmed ABDOU, Tomohiro TAKAGAKI, Ali ALGHAMDI, Antonin TICHY, Toru NIKA ...
    Type: research-article
    Article ID: 2020-049
    Published: 2020
    [Advance publication] Released: November 07, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The effect of various pretreatments on the bonding of a resin cement to resin-composite CAD/CAM blocks (RCBs) was examined. The surface of dispersed-filler RCBs (DF-RCBs) and a polymer infiltrated ceramic network RCB (PICN-RCB) was roughened using hydrofluoric acid etching (HF) or sandblasting, and followed by silanization and/or universal adhesive (UA) application. Microtensile bond strength (µTBS), surface roughness parameters (arithmetical mean height (Sa); developed interfacial area ratio (Sdr)), and critical surface energy (γc) were determined. For most DF-RCBs, the highest µTBS was obtained using HF+UA. UA application to DF-RCBs resulted in similar or higher µTBS compared to silanization, which indicates that silane treatment is not crucial for DF-RCBs, especially after HF. In contrast, the highest µTBS to PICN-RCB was obtained with silanization. Both roughening pretreatments significantly increased the surface roughness parameters and the γc of all RCBs. The γc was positively correlated with Sa (r=0.756, p<0.001) and Sdr (r=0.837, p<0.001).

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  • Piyaphong PANPISUT, Thunchanok SUPPAPATPONG, Athiporn RATTANAPAN, Pata ...
    Type: research-article
    Article ID: 2020-056
    Published: 2020
    [Advance publication] Released: November 07, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The aim was to develop dual-cured, self-adhesive composites containing monocalcium phosphate monohydrate (MCPM, 8 or 4 wt%) and nisin (6 or 3 wt%) with added adhesive monomer. The effect of additives on monomer conversion (MC), biaxial flexural strength (BFS), dentin shear bond strength (SBS), and surface apatite formation were examined. All experimental composites showed light-activated MC (70–75%) higher than the commercial self-adhesive composite (Vertise Flow; VF, 65%). The additives reduced BFS of the composites from 217 to 133 MPa. SBS of the experimental composites (2–6 MPa) was lower than that of VF (12 MPa). Rising MCPM level enabled apatite-like crystals precipitated on the surface of composites after immersion in simulated body fluid for 4 weeks. The additives showed negligible effect on MC and SBS. Rising level of additives reduced strength of the composites but the values were still higher than that required by the standard.

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  • Erick LUZ MADRIGAL, Antonin TICHY, Keiichi HOSAKA, Masaomi IKEDA, Masa ...
    Type: research-article
    Article ID: 2020-077
    Published: 2020
    [Advance publication] Released: November 07, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The effect of curing mode of dual-cure resin cements on the tensile bond strength (TBS) of universal adhesives to enamel, dentin, zirconia, lithium disilicate ceramics (LDS), feldspathic porcelain (FP), and a Pd-Au alloy was evaluated. The substrates were bonded using Tokuyama Universal Bond (TUB) or Scotchbond Universal Adhesive (SBU), followed by luting with Estecem II (ECII) or Rely-X Ultimate (RXU), respectively, which were used either in light-curing or self-curing mode. The TBS test was performed after 24 h or 5,000 thermal cycles. Light-curing significantly improved the 24-h TBS of TUB/ECII to enamel, dentin and FP, as well as the TBS of SBU/RXU to all substrates except LDS. After thermal cycling, light-curing significantly increased the TBS of both adhesives/cements to dentin, but significant differences between curing modes were seldom observed for other substrates. This suggested that light-curing is essential for the hydrophilic dentin, but self-curing might be sufficient for other substrates.

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  • Yong-jie WEI, Yuan-yuan CHEN, Qing-song JIANG
    Type: research-article
    Article ID: 2019-340
    Published: 2020
    [Advance publication] Released: October 27, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The dimensional stability of core buildup materials plays an important role in clinical application. In this study, hygroscopic dimensional changes of four commercial core buildup materials were investigated in deionized water and artificial saliva for up to 150 days. Specimens were made within a customized cylindrical mold. The initial mass and the apparent mass in liquids were measured. All the tested materials showed hygroscopic expansion after a 150-days immersion time. Hygroscopic expansion of these four materials can partly compensate for the polymerization shrinkage. SDR showed the lowest hygroscopic expansion of the four tested materials when immersed in deionized water and artificial saliva. PC showed the highest hygroscopic expansion in deionized water, while LC showed the highest hygroscopic expansion in artificial saliva. In the case of different immersion solvents, osmotic pressure should be considered. For hygroscopic dimensional changes, the hydrophilicity of monomers and changes of intermolecular forces may be crucial factors.

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  • Ali AL-QAHTANI, Go INOUE, Ahmed ABDOU, Toru NIKAIDO, Junji TAGAMI
    Type: research-article
    Article ID: 2020-019
    Published: 2020
    [Advance publication] Released: October 27, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The aim of this study was to investigate the effects of potassium fluoride (KF) and sodium fluoride (NaF) in different concentrations on micro-shear bond strength (µSBS) and their protective effects against acid. The enamel blocks were treated with several concentrations of KF and NaF. For µSBS, Clearfil SE Bond 2 was applied to the treated surface and resin composite was light-cured, then examined using a universal testing machine. For acid resistance test, the specimens were immersed in acidic solution (pH 4.5), then examined under 3D confocal laser scanning microscope (CLSM). In µSBS, KF at 1,000, 9,000, and 10,000 ppm did not show differences compared with the control, while other concentrations of KF and NaF led to decreased µSBS. Higher concentrations of NaF and KF showed higher resistance to the acid challenge. So, we concluded that various concentrations of KF and NaF solutions had specific effects on µSBS and acid resistance.

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  • Can SHAO, Xin ZHANG, Jing YE, Ya-Chong LI, Yi-Jun BAO, Zhi-hui LI, Yin ...
    Type: research-article
    Article ID: 2020-055
    Published: 2020
    [Advance publication] Released: October 27, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    This study aimed to investigate the effect of Deoxyribonuclease I (DNase I) coating on initial adhesion and biofilm formation of peri-implant bacteria. Titanium (Ti), Ti-polydopamine (Ti-PDOP), Ti-PDOP-DNase I and Ti-PDOP-inactivated DNase I samples were studied. The FE-SEM, EDS and XPS were used to confirm that DNase I was coated onto Ti. The initial adhesion and biofilm formation of Aggregatibacter actinomycetemcomitans (A.a) and Fusobacterium nucleatum (F.n) were observed by CLSM. The osteogenic induction of Ti-PDOP-DNase I on MC3T3-E1 cells was investigated by ALP activity and RT-PCR. The adhesion clearance rate of viable bacteria on the surfaces of Ti-PDOP-DNase I was 91.95% for A.a, and 96.37% for F.n, and the 24 h biofilm formation of the bacteria was significantly inhibited. In addition, on DNase I coating, the mRNA level of osteogenic marker genes (alp, opn, bsp, sp7) and the activity of ALP were both up-regulated. Therefore, DNase I coating could be an alternative approach for preventing implant-related infection.

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  • Yuko NAGASAWA, Yasushi HIBINO, Yoshikazu EDA, Hiroshi NAKAJIMA
    Type: research-article
    Article ID: 2019-431
    Published: 2020
    [Advance publication] Released: October 24, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    This study examined the effects of sandblasting, hydrofluoric acid etching and priming on the shear bond strength of self-adhesive resin cement between seven different CAD/CAM resin composites and a resin composite core material at 24-h after cement mixing. Five surface treatments [control (C), sandblasting (S), priming (P), sandblasting with priming (SP), and 9% HF etching with priming (HFP)] were performed respectively for disc specimens of CAD/CAM blocks. There were no significant differences in bond strength among the C, S, and P, except for one block (p>0.05). SP showed a greater bond strength than S. Weibull moduli were not changed significantly among all treatments for all blocks, whereas the strengths with 5% and 95% failure probability of SP and HFP showed greater values than the others. The bond strengths of HFP were comparable to those of SP. Priming after sandblasting or HF etching could be effective to increase the bond strength of CAD/CAM blocks.

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  • Camilla JOHANSSON, Jasmin DIBES, Luis Emilio LÓPEZ RODRIGUEZ, Evaggeli ...
    Type: research-article
    Article ID: 2020-039
    Published: 2020
    [Advance publication] Released: October 24, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The purpose of the study was to evaluate the accuracy: trueness and precision of photopolymers used for dental models and surgical guides printed with two different digital light processing (DLP) printers. Forty specimens of four materials; E-dentstone®, E-shell®, NextDent™ Model, NextDent™ SG, and two designs; models A and B (n=5), were manufactured (DDDP, EvoDent). Trueness was evaluated by comparing values for 26 parameters with the CAD models’ reference values and precision through standard deviation. The trueness and precision were higher for linear than for angle parameters. X- and Y-axes showed higher trueness than Z-axis and model B higher trueness than model A. The conclusions are; the accuracy is dependent on the design of the object. The linear precision appears to be high. The highest trueness was observed for a surgical guide polymer (NextDent™ SG). The definition of clinically relevant accuracy and acceptable production tolerance should be evaluated in future studies.

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  • PaPa KAYKHINE, Antonin TICHY, Ahmed ABDOU, Keiichi HOSAKA, Richard M. ...
    Type: research-article
    Article ID: 2020-057
    Published: 2020
    [Advance publication] Released: October 24, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The effect of warm air-blowing on the sealing ability of two one-bottle and one two-bottle silane-containing universal adhesives (UAs) applied to lithium disilicate ceramics (LDS) was evaluated. Tapered cavities prefabricated in LDS blocks (IPS e.max CAD) were treated by the adhesives, air-blown either with normal air (23±1°C) or warm air (60±5°C), and filled with a flowable resin composite. Interfacial gap formation was observed using swept-source optical coherence tomography immediately after filling, after 24 h, 5,000 and 10,000 thermal cycles, and an additional 1-year water storage. Specimens bonded using normal air-blown one-bottle UAs exhibited a significantly higher gap formation than the two-bottle UA (p<0.001), and detached within 24 h. Warm air-blowing significantly decreased the gap formation of one-bottle UAs (p<0.001), but the specimens dislocated within 24 h or during thermocycling. The two-bottle UA withstood all aging procedures and warm air-blowing significantly decreased its 1-year gap formation compared to normal air-blowing (p=0.002).

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  • Oskar BUNZ, Carla I. BENZ, Wolfgang H. ARNOLD, Andree PIWOWARCZYK
    Type: research-article
    Article ID: 2019-300
    Published: 2020
    [Advance publication] Released: October 20, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    High performance polymers like PEEK (polyetheretherketone) and FRC (fiberreinforced composite) could substitute metallic alloys for removable partial dentures. However, these polymers require aesthetic veneering. This study was to determine the bond strength to direct composite. Specimens made of PEEK and FRC were produced and air-abraded (50 μm aluminum-oxide). Specimens were allocated to four experimental groups: Luxatemp Glaze & Bond, Scotchbond Universal, SR Nexco Connect and iBond Universal. Specimens were divided into three subgroups for short-term, long-term and no artificial aging and shear bond strength (SBS) was evaluated. SBS of specimens made of PEEK with no artificial aging showed values between 10.79–14.00 MPa, short-term artificial aging resulted in values between 3.78–13.85 MPa and after long-term artificial aging SBS decreased to 0–8.75 MPa. SBS measurement of FRC specimens resulted in values between 9.83–12.1 MPa without aging, after short-term artificial aging values decreased to 8.36–11.98 MPa and after long-term aging SBS showed a degradation to 4.52–7.82 MPa.

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  • Jenni HJERPPE, Leila PEREA-LOWERY, Lippo V.J. LASSILA, Pekka K VALLITT ...
    Type: research-article
    Article ID: 2019-389
    Published: 2020
    [Advance publication] Released: October 20, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The objective of this study was to compare potassium hydrogen difluoride (KHF2) etching for zirconia with commonly used surface roughening and chemical bonding methods (silane, MDP-monomer primer) for resin-based luting cement bonding to zirconia. Zirconia specimens were divided into six groups (n=10) according to surface treatment and bonding procedures, with and without thermocycling (6,000 cycles, 5–55ºC): 1) air-borne particle abrasion with alumina+MDP-monomer (ABP), 2) air-borne particle abrasion with silica-coated trialuminium trioxide+silane (ABPR-S) and 3) KHF2 etching+silane (ETC). Surface roughness and bond strength (SBS-test) for dry and thermocycled specimens were measured. SBS did not vary statistically between the dry groups, but thermocycling decreased the bond strengths of all the tested methods (p<0.05). After thermocycling, ABP had statistically significantly lower bond strength values compared to ABPR-S and ETC (p<0.05). Etching method with KHF2 did not provide better bonding capacity to previously introduced and commonly adopted bonding methods.

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  • Guang HONG, Zhen CHEN, Jian-min HAN, Wei-qi WANG, Ping GAO, Keiichi SA ...
    Type: research-article
    Article ID: 2020-079
    Published: 2020
    [Advance publication] Released: October 20, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The purpose of this study was to investigate the effect of amylase activity on the mechanical properties of three dental composite resin (Filtek Z350; Filtek Z250 and Polofil Supra). The specimens were immersed in amylase solution at four different activities (25, 50, 100 and 200 KIU/L) with an artificial saliva solution (AS) as a control. The flexural strength (FS) and elastic modulus (EM) were determined in a three-point bending test after immersion for periods up to 12 months. In addition, surface roughness and surface morphology also determined. The FS of Filtek Z350 reaching the lowest level of 67.86 MPa after AS immersion for one year. There was a general trend for FS to decrease following immersion in AS for all the tested materials. However, the amylase groups did not undergo a significant decrease in FS and EM, and there was a slight increase in FS and EM for Polofil Supra.

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  • Naho SUEISHI, Tomoko OHSHIMA, Takashi OIKAWA, Hiroshi TAKEMURA, Mai KA ...
    Type: research-article
    Article ID: 2018-355
    Published: 2020
    [Advance publication] Released: October 15, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    During orthodontic treatment, plaque tends to form around fixed orthodontic appliances, which increases the risk of dental caries. It has been reported that ultarafine bubble with a diameter <1 μm water (UFBW) effectively removes organic matter. In addition, UFBW is harmless and stable for at least one month with refrigeration. The aim of this study was to examine the plaque-removal effect of ultrafine bubble water (UFBW) to establish a new method to prevent dental caries in patients during orthodontic treatment procedures. The in vitro study examined different concentrations of UFBW and compared the cleaning effect to that of existing mouthwashes. High-concentration UFBW (HUFBW) was most effective in cleaning. In the subsequent clinical study, HUFBW showed a significantly higher plaque-removal effect compared to distilled water (p<0.01). Thus, supplementary use of HUFBW could decrease the incidence of dental caries during orthodontic treatment.

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  • Vellore Kannan GOPINATH, Sheela SOUMYA, V. YOGESHWAR CHAKRAPANI, T.S. ...
    Type: research-article
    Article ID: 2020-005
    Published: 2020
    [Advance publication] Released: October 15, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The objective of this study was to develop electrospun polycaprolactone (PCL) membranes blended with hydroxyapatite (HA) and evaluate its potential in differentiating inflamed dental pulp stem/progenitor cells (IDPSCs) into odontoblasts. Electrospun nanofibrous membrane consisting of PCL blended with 10 wt% and 15 wt% of HA were fabricated and the characterization was done by Scanning electron microscopy (SEM), Fourier- transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and contact angle analysis. Cytocompatibility, cell adhesion and odontogenic differentiation ability of the membranes were assessed by MTT, Live/Dead, SEM/DAPI and qPCR studies. The mineral deposition ability of the membranes with IDPSCs was estimated by SEM-EDS. The SEM analysis revealed a nanofibrous texture with an average fiber diameter of 140 nm for PCL, 220 nm for PCL10%HA and 250 nm for PCL15%HA. Among the membranes tested, PCL10%HA favored positive cell attachments, upregulated expression of DSPP and ALP gene and higher Ca/P ratio compared to PCL and PCL15%HA.

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  • Mayumi OIKAWA, Hiroshi MASUMOTO, Naru SHIRAISHI, Yusuke ORII, Takahisa ...
    Type: research-article
    Article ID: 2020-051
    Published: 2020
    [Advance publication] Released: October 15, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    Ti-6Al-4V alloy is used as biomaterials for dental and orthopedic implants because of their excellent biocompatibilities and mechanical properties. However, it is unclear that electron cyclotron resonance (ECR) plasma oxidation can create the oxide films on Ti-6Al-4V alloy surface, and this technique improves the ability of its osseointegration. The purpose of this study was to investigate the characteristics and calcification ability of the oxide films. X-ray diffraction (XRD) peaks of rutile phase were intensified with increasing the temperature. Scanning electron microscopy (SEM) images showed a crater-like structure, and bonding strengths between the substrate and oxide film reached a maximum at 400°C. Calcium phosphate (CaP) compounds after calcification process were identified as octacalcium phosphate (OCP) and precipitation amount was maximized at 400°C. The results suggested that the altered surface of Ti-6Al-4V alloy by ECR plasma oxidation might have the potential of accelerating the ability of its osseointegration through enhancement of OCP.

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  • Yen-Hao CHANG, Chen-Yi LEE, Ming-Sung HSU, Je-Kang DU, Ker-Kong CHEN, ...
    Type: research-article
    Article ID: 2019-226
    Published: 2020
    [Advance publication] Released: October 08, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    We evaluated the effect of toothbrush/dentifrice brushing on the weight variation and surface properties of different denture bases. Four denture base materials (conventional heat cure, high impact, CAD/CAM, and polyamide resins) were subjected to toothbrushing abrasion (50,000 strokes). The weight value, surface roughness, and topography of each group were determined before and after toothbrushing. The hardness was measured by the Vickers hardness test. Data were analyzed using ANOVA and Bonferroni tests. After toothbrushing, the weight of the polyamide resin had significantly increased; significant weight losses were observed for conventional heat cure and high impact resins, but none for the CAD/CAM resin. The surface roughness of each group increased significantly owing to the wear caused by toothbrushing. The weight variation and surface roughness were not affected by the hardness. Our results suggested that denture base materials deteriorate after brushing with toothpaste, in which the polyamide resin exhibited lower levels of abrasion.

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  • Bebek Serra OGUZ AHMET, Roda SESEOGULLARI-DIRIHAN, Arzu TEZVERGIL-MUTL ...
    Article ID: 2019-304
    Published: 2020
    [Advance publication] Released: October 08, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The study evaluated changes in total enzymatic activity and degradation of demineralized dentin following the application of universal or self-etch adhesives. The universal adhesives —Scotchbond Universal (SU) and All-Bond Universal (ABU) and self-etch adhesives —Adper Easy Bond (EB) and G-aenial Bond (GB) were used for 2 min pretreatment of the dentin beams. Phosphoric acid (PA) treatment as well as no treatment served as controls. Total enzymatic activity was analyzed before and after treatment, collagen degradation was assessed using mass loss, C-terminal telopeptide (CTX) and C-terminal-telopeptide of type I collagen (ICTP) release (24 h, 3-day, 3-week). Over three weeks of incubation, ICTP release of ABU treated beams was significantly higher than other groups (p<0.05), except for SU treated beams (p>0.05) and CTX release of GB treated beams was the highest among the groups with statistically significant difference (p<0.05). The results confirm that the universal adhesives tested have also potential to increase the enzymatic activity in dentin.

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  • Daniela K. ZELLER, Jens FISCHER, Nadja ROHR
    Type: research-article
    Article ID: 2019-313
    Published: 2020
    [Advance publication] Released: October 08, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The objective of this study was to analyze the viscous behavior during setting reaction of resin composite cements and how it is influenced by temperature. Viscous properties during auto-polymerization at 23°C of three adhesive (Panavia V5 [PV5]; RelyX Ultimate [RUL]; Multilink Automix [MLA]) and three self-adhesive (Panavia SA plus [PSA]; RelyX Unicem 2 Automix [RUN]; Multilink SpeedCem [MSC]) resin composite cements were rheometrically measured. Changes in contact angle and temperature during auto-polymerization were evaluated for each cement at 23°C and 37°C. Rheological analysis and temperature measurements corresponded in terms of curve progression. The tested resin composite cements demonstrated strong variations in their viscous behavior during setting reaction. PV5 and PSA become less viscous at 37°C and then polymerize quickly. For RUL and RUN at 37°C, viscosity rises, and polymerization takes place quickly. MLA and MSC start with high viscosity, then MSC polymerizes very fast and MLA rather slowly.

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  • Pasi ALANDER, Leila PEREA-LOWERY, Kalevi VESTERINEN, Auli SUOMINEN, Ei ...
    Type: research-article
    Article ID: 2019-428
    Published: 2020
    [Advance publication] Released: October 08, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    This study evaluates the effect of fiber reinforcement quantity and position on fracture load of fixed dental prostheses specimens with different fibre reinforced composite (FRC)/ particulate filler composite (PFC) ratio in a cantilever beam test. Three types of specimen structures where made: Specimens with FRC, PFC, or with a combination of both. Specimen’s size was 2.0×2.0×25 mm3 and the thicknesses of the FRC layers were 0, 0.5, 1.0, 1.5 and 2.0 mm. The layers of FRC were placed at the top or at the bottom. Eight groups of specimens were evaluated (n=15/group). The test specimens were statically-loaded until fracture. The fracture loads were linearly dependent on the quantity of the FRC reinforcement when placed at the top (R2=0.941) and bottom (R2=0.896) of the specimens. ANOVA revealed that reinforcement position on the tension side and higher FRC reinforcement volume in the test specimens had positive effect to load bearing capacity (p<0.001).

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  • Chengzhong WU, Xia SHAO, Xianglin LIN, Weijin GAO, Yiming FANG, Jingxi ...
    Type: research-article
    Article ID: 2019-249
    Published: 2020
    [Advance publication] Released: October 07, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The aim of this study was to evaluate the effects of a collagen/hyaluronic acid coating without or with incorporated heterodimeric bone morphogenetic protein 2/7 (BMP2/7) on in-vitro osteoblastic differentiation on titanium discs. The multilayer collagen/hyaluronic acid coatings without or without incorporated BMP2/7 were deposited on titanium discs via a layer-by-layer technique. The effects of the coatings were evaluated by assessing the alkaline phosphatase (ALP) activity (an early osteoblastic differentiation marker) and the osteocalcin expression (a late osteoblastic differentiation marker). The expression levels of the osteoblastic genes, such as alkaline phosphatase 2 (AKP2) and osteocalcin (OC) were detected using real-time RT-PCR. ALP activity and OC expression were significantly increased when cells were cultured with collagen/hyaluronic acid+BMP2/7 heterodimer (p<0.05). The same result was found in cells with the expression of a BMP2/7 fusion gene, OC and AKP2. These results indicated that collagen/hyaluronic acid+BMP2/7 heterodimer-coated discs might have the potential to greatly enhance osseointegration than a either BMP2 or BMP7 solution or a mixture of BMP2 and BMP7 BMP2/7.

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  • Yinchen LIU, Lin HAN, Hongye YANG, Siying LIU, Cui HUANG
    Type: research-article
    Article ID: 2019-255
    Published: 2020
    [Advance publication] Released: October 07, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    Apigenin is a type of flavonols that exhibits anti-caries properties. Bacterial adherence is the initial step in the forming of a stable biofilm that leads to caries. Bacterial adherence is affected by surface characteristics, including hydrophobicity and bacterial aggregation. However, the effect of apigenin on surface characteristics of cariogenic bacteria has not been reported. We aimed to examine the effects of apigenin on adherence and biofilm formation of Streptococcus mutans UA159. Hydrophobicity and bacterial aggregation, pac and gbpC gene expressions, and cytotoxicity on human dental pulp cells were also determined. Apigenin significantly inhibited the adherence and biofilm formation of S. mutans. Hydrophobicity decreased, whereas the aggregation rate was significantly increased compared with the control. Apigenin significantly suppressed pac and gbpC gene expressions. Apigenin exhibited acceptable biocompatibility on hDPCs. Thus, apigeinin may affect adherence and biofilm formation by altering the surface properties of S. mutans without obvious adverse effect on hDPCs.

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  • Masayoshi MORITA, Haruaki KITAGAWA, Katsuya NAKAYAMA, Ranna KITAGAWA, ...
    Type: research-article
    Article ID: 2019-351
    Published: 2020
    [Advance publication] Released: October 07, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    Mineral trioxide aggregate (MTA) cements are used in direct pulp capping and many other applications, and several types of these products have been commercialized. The aim of this study was to examine the antibacterial effects and mineral induction abilities of three conventional MTA cements and one resin-modified MTA cement. Agar diffusion tests revealed that, after setting, all four cements exhibited little antibacterial effects against Enterococcus faecalis and Streptococcus mutans, with no significant differences among the materials. After 24 h, E. faecalis and S. mutans suspensions incubated in the presence of each cement did not exhibit reduced numbers of viable bacteria, compared with those same bacterial suspensions incubated without any cement; this indicated that none of the cements inhibited bacterial growth. Furthermore, the resin-modified MTA cement exhibited lower mineral induction ability, compared with that of the three conventional MTA cements.

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  • Hongzhou SHEN, Yin ZHI, Fangxing ZHU, Jiawen SI, Jun SHI, Steve GF. SH ...
    Type: research-article
    Article ID: 2019-437
    Published: 2020
    [Advance publication] Released: October 07, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    In this study, we proposed BMP2-incorporated calcium phosphate cement (BMP2-CPC), for application in guided bone regeneration (GBR) and compared the experimental bone restoration performance and clinical alveolar bone reconstruction outcome of BMP2-CPC with those of deproteinized bovine bone (DBB). The animal study indicated that, compared to DBB, which induced the slow ingrowth of new bone, BMP2-CPC induced numerous small growth centers for bone regeneration and facilitated a significant amount of bone regeneration in rabbit calvarial bone defects. Fewer residual graft particles remained in the BMP2-CPC-treated defects than in the DBB-treated defects. The clinical study indicated that BMP2-CPC was similar to DBB in remedying alveolar bone insufficiency and maintaining implant stability. In conclusion, the results of this present study indicate that compared to DBB, BMP2-CPC can significantly enhance in vivo bone regeneration and remodeling in rabbit calvarial bone defects and shows preliminary support on its clinical application in GBR surgeries.

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  • Eri TOKUNAGA, Noriyuki NAGAOKA, Yukinori MARUO, Kumiko YOSHIHARA, Goro ...
    Type: research-article
    Article ID: 2020-029
    Published: 2020
    [Advance publication] Released: October 07, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    This study aimed to investigate whether inorganic elements of polymer-infiltrated ceramic (PIC) and microfilled resin (MFR) for CAD/CAM would affect initial bond strength to luting agent. Inorganic elements of PIC and MFR were different with shape and ingredient observed by SEM, STEM and EDS. Microtensile bond strengths (µTBS) value of PIC was increased by 10-methacryloyloxydecyl dihydrogen phosphate (MDP) and acetic acid (AA)- or MDP-activated silane treatment, and further increased by succeeding heat treatment (HT). The µTBS of MFR was increased by MDP and MDP-activated silane, but decreased by AA-activated silane without HT. The HT improved the µTBS of MFR with AA-activated silane, but conversely for MDP-activated silane. Only in MFR, phosphoric acid (PA) application before each surface treatment dramatically decreased the µTBS of AA-activated silane. FTIR peaks in MFR shifted according to phosphate group’s peak. MFR would possess high phosphate group adsorption capacity, with MDP effectively improving its bonding capability.

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  • Mahmut Sertaç ÖZDOĞAN, Mustafa GÜNGÖRMÜŞ, Ali ÇELİK, Gülsüm TOPATEŞ
    Type: research-article
    Article ID: 2020-134
    Published: 2020
    [Advance publication] Released: October 07, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    Silicon nitride (Si3N4) is one of the promising ceramics for dental restoration due to providing significant benefits during the application. This study aimed to investigate the potential use of Si3N4 for all-ceramic dental restorations by characterizing some critical properties as color shade, mechanical resistance, shear-bond strength and radiolucency. For our study, porous Si3N4 ceramic was produced by partial sintering process with limited amounts of sintering additives and low temperature. A commercial ZrO2 ceramic was prepared according to manufacturer’s instructions and results were compared with Si3N4. Si3N4 is an attractive ceramic for dental applications with good mechanical properties even in porous form, it has additional advantages over the conventional ceramics used as restorative material, such as, inherent antibacterial/anti-infective activity, radiolucency, and lower hardness. It is expected that Si3N4 will become popular in dental applications as well.

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  • Giovanna Speranza ZABEU, Letícia Ferreira Freitas BRIANEZZI, Rafael Si ...
    Type: research-article
    Article ID: 2019-335
    Published: 2020
    [Advance publication] Released: October 01, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    This study aimed to analyze the interaction of a MDP-based universal dentin bonding system (DBS) with Er, Cr: YSGG laser irradiation, measuring the microtensile bond strength to dentin over a six-month period. The experimental design involved three factors: DBS (Adper Scotchbond Universal; Clearfil SE Bond, Adper Scotchbond Multipurpose and Adper Single Bond 2), laser (Control and Er, Cr: YSGG), and time (initial- 7 days and 6 months). Eighty dentin samples from molars were prepared (n=10) with laser irradiation after primer and DBS application. After 7 days, were subjected to micro tensile bond strength test. The data were analyzed by three-way ANOVA and Tukey tests (p<0.05). Both DBS and laser significantly affected the bonding performance and their interaction was statistically significant (p=0.0194). The self-etching mode of the MDP-based universal DBS maintained the bond strength on dentin irradiated with ER, Cr: YSGG after 6 months, while bonding with all other DBS deteriorated.

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  • Afnan O. AL-ZAIN, Jeffrey A. PLATT
    Type: research-article
    Article ID: 2020-002
    Published: 2020
    [Advance publication] Released: October 01, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    This study investigated the influence of curing distance on µ-flexural strength (µ-FS) of a nano-hybrid composite, cured using the manufacturer-recommended curing time (MCT), compared to a consistent radiant exposure (CRE) using three different light-curing units (LCUs). Beams (6×2×1 mm) were cured using the MCT or CRE with a quartz-tungsten-halogen (QTH); a single-emission-peak light-emitting-diode (SLED), or a multiple-emission-peak light-emitting-diode (MLED) LCU. Specimens were cured at 0-, 2- or 8-mm distances (n=10) and the bottom irradiance and CRE were measured using a Managing Accurate Resin Curing-Resin Calibrator spectrometer. µ-FS testing was performed, and data analyzed using two-way ANOVA and Tukey multiple comparison tests (α=0.05). Mean bottom irradiance was (25.4–99.7 mW/cm2) and CRE (0.31–1.11 J/cm2). µ-FS was 422.1–516.6 MPa (MCT) and 440.4–490.4 MPa (CRE). Comparing CRE to MCT showed that µ-FS significantly decreased using the CRE at 2-mm (QTH) or the MCT at 2- and 8-mm (SLED). µ-FS may be significantly impacted by the curing protocol.

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  • Ryotaro NAKANO, Shinya HOMMA, Takuya TAKANASHI, Tomoki HIRANO, Yoshita ...
    Type: research-article
    Article ID: 2020-030
    Published: 2020
    [Advance publication] Released: October 01, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The objective of this study was to investigate the effects of eccentric cyclic loading on implant components using the internal joint system with titanium and zirconia abutments. Abutments were made of either pure titanium (Ti group) or zirconia (TZP group). Cyclic loading test was conducted according to the specifications of ISO 14801. Loading condition was at 2 points assuming axial load and eccentric load. The reverse torque value reduced after the eccentric load and reduced more in the TZP group than the Ti group. Marginal gap changed after eccentric loading, and was greater in the TZP group. In the TZP group, changes in configuration were observed in the implant body, and Ti was detected on the abutment surface. From the above, the eccentric load may have worse effects than axial loads. It was suggested that the TZP group was clinically disadvantageous compared to the Ti group.

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  • Takashi MATSUURA, S. M. ZIAUDDIN, Viviane K. S. KAWATA-MATSUURA, Kouji ...
    Type: review-article
    Article ID: 2020-043
    Published: 2020
    [Advance publication] Released: October 01, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The aim of this review is to evaluate the long-term effectiveness of calcium silicate-based cement (CS) and calcium hydroxide (CH) for direct pulp capping (DPC) to human pulp-exposed permanent teeth. An electronic search and manual search were performed on 21 June 2019. Long-term clinical and radiographic evaluations of the effectiveness of CS and CH for DPC to human pulp-exposed teeth were included, and data extraction, risk-of-bias assessment and meta-analyses were performed. From 645 identified articles, 7 articles met the eligibility criteria. The meta-analyses comparing CS with CH and Biodentine with mineral trioxide aggregates (MTA) on DPC success rate were performed, and significant difference was observed between CS and CH (risk ratio=1.20; p=0.005), whereas no significant difference was observed between Biodentine and MTA. CS seems to be a more effective and predictable DPC material than CH; however, these analyses are based on the studies judged at high risk of bias.

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  • Yuko TAJIRI-YAMADA, Atsushi MINE, Hayaki NAKATANI, Asuka KAWAGUCHI-UEM ...
    Type: research-article
    Article ID: 2020-132
    Published: 2020
    [Advance publication] Released: October 01, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The effect of cleaner containing 10-methacryloyloxydecyl dihydrogen phosphate (MDP) for removing temporary cement remnants on dentin surface was evaluated. Flat dentin surfaces were wet-polished (Co) and HY-BOND temporary cement hard (Shofu) was applied to the surface. This temporary cement was removed using an air-scaler (Sc), brush (Br), or phosphoric acid and NaOCl (NC). A prototype cleaner containing MDP (Kuraray Noritake Dental, Tokyo, Japan) was used with agitation mode (MC+AG). KATANA Avencia block (Kuraray Noritake Dental) was luted with SA Cement Plus Automix (Kuraray Noritake Dental). Co showed significantly higher bond strength than Sc or Br (p<0.001 each). Bond strengths with NC (p=0.99) and MC+AG (p=0.38) did not differ significantly from that with Co. Transmission electron microscopy revealed sufficient interaction of MC+AG. Cleaner containing MDP can effectively remove temporary cement by agitation, and can be expected to improve the chemical bonding ability by binding more MDP to dentin.

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  • Seong-Hee MOON, Sang Hee JI, Ju-Lee SON, Seong-Jin SHIN, Seunghan OH, ...
    Type: research-article
    Article ID: 2020-157
    Published: 2020
    [Advance publication] Released: October 01, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    This study aimed to investigate the inhibitory effects of Colocasia antiquorum var. esculenta (CA) on Porphyromonas gingivalis (P. gingivalis) growth, inflammation, and osteoclastogenesis. CA was effective in inhibiting the growth of P. gingivalis when applied together with an experimental fluoride varnish. CA also significantly decreased the release of interleukin-6, tumor necrosis factor-α, and nitric oxide from lipopolysaccharide-induced RAW 264.7 cells. No significant differences in viability were noted between the cells treated with CA and the controls. In addition, CA significantly attenuated osteoclast differentiation on bone marrow macrophages. In conclusion, CA inhibited the growth of P. gingivalis and showed anti-inflammatory and anti-osteoclastogenic effects. Therefore, CA may have the potential to act as a novel natural agent for preventing periodontitis.

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  • Rawa Omar IBRAHIM, Abdulsalam Rashid AL‑ZAHAWI, Laith Abed SABRI
    Type: research-article
    Article ID: 2020-053
    Published: 2020
    [Advance publication] Released: September 30, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    An endodontic post is required to retain and support the core restoration in case of insufficient remaining coronal dentin after root canal therapy. This study analyzed the biomechanical and thermal behavior of PEEK prefabricated post after choosing the head design that produces the least amount of stress on the core and remaining tooth structure. These results were compared with the most common commercially available prefabricated post, which is titanium and glass fiber post. Thus a CBCT scanning of a maxillary central incisor with its supporting structure was used to construct a 3D solid model of an endodontically treated teeth for finite element analysis (FEA). The restored tooth with the spherical head design of PEEK prefabricated post yielded a more benign stress distribution and repairable failure mode on the crown, luting cement, core, and dentin under both mechanical and thermal loads, followed by glass fiber post and titanium post respectively.

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  • Erika NISHIDA, Hirofumi MIYAJI, Kanako SHITOMI, Tsutomu SUGAYA, Tsukas ...
    Type: research-article
    Article ID: 2019-176
    Published: 2020
    [Advance publication] Released: September 29, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    Zinc-fluoride glass nanoparticles (Zinc-F) release several ions, such as fluoride, zinc and calcium ions, through acid-base reactions. The aim of this study was to evaluate the antibacterial and cytotoxic properties of Zinc-F. Antibacterial tests showed that a Zinc-F eluting solution significantly reduced the turbidity and colony-forming units of Streptococcus mutans and Actinomyces naeslundii, compared to that of calcium-fluoroaluminosilicate glass nanoparticles without zinc ions. In live/dead staining, Zinc-F eluate significantly decreased green-stained bacterial cells, indicating live cells, compared with the control (no application). Human dentin coated with Zinc-F showed suppressed S. mutans and A. naeslundii biofilm formation. Additionally, Zinc-F eluate showed low cytotoxic effects in osteoblastic and fibroblastic cells. Therefore, our findings suggested that Zinc-F exhibits antibacterial and biocompatible properties through multiple-ion release.

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  • Manop KHANIJOU, Rui ZHANG, Kiatanant BOONSIRISETH, Ratchapin LAOVANITC ...
    Type: research-article
    Article ID: 2019-341
    Published: 2020
    [Advance publication] Released: September 29, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    To analyze physicochemical such as surface structures, the crystallinity, chemical composition, calcium phosphate dissolution and osteogenic properties of tooth derived bone substitute (TDBS) processed chair-side and other grafting materials. The number of anaerobic and facultative anaerobic bacteria in the supernatant of processed TDBS was determined. Human osteoblasts were co-cultured with TDBS or allograft in transwell system to examine cell migration. BMP2 released from TDBS was measured by ELISA. TDBS had high crystallinity similar to BoneCeramic while it had a broad pattern to ramus bone, OraGRAFT, and Bio-Oss. TDBS contained carbon, calcium, oxygen, phosphate, sodium and magnesium elements like others. Calcium/phosphorus dissolution of TDBS show closely related to those of mandibular ramus bone and OraGRAFT. In addition, microbial decontamination of TDBS by the chemical processing revealed a hundred percent efficacy. The osteoconductive and osteoinductive properties demonstrated in the TDBS processed chairside suggested the potential of an alternative for bone grafting material.

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  • Sherif ADEL, Takahiro WADA, Nobuyuki KAWASHIMA, Ahmed ABDOU, Hiroshi W ...
    Type: research-article
    Article ID: 2019-414
    Published: 2020
    [Advance publication] Released: September 29, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    This study evaluated tristrontium aluminate (S3A) and its viability as a component for tricalcium silicate (C3S) cements. The properties of S3A, C3S, and S3A/C3S mixtures were evaluated in terms of setting time, compressive strength, flowability, and radiopacity. X-ray diffraction (XRD) pattern verified the powder synthesized in the laboratory as S3A, consequently, confirming the preparation method. S3A exhibited the lowest setting time, followed by C3S and S3A/C3S mixtures. Compressive strength of C3S was significantly higher than S3A. The S3A/C3S mixture showed comparable compressive strength to C3S for 1-day post initial mixing. There was no significant difference in flowability between S3A/C3S and mineral trioxide aggregate (MTA). S3A showed comparable radiopacity to MTA, whereas that of the S3A/C3S mixture was significantly lower comparatively; however, it achieved sufficient radiopacity (3 mm aluminum thickness equivalent). Further studies are needed to improve the manufacturing process of S3A and evaluate the bioactive effect of strontium.

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  • Bochun MAO, Yu XIE, Hanjiu YANG, Chenhao YU, Pingchuan MA, Ziying YOU, ...
    Type: research-article
    Article ID: 2019-325
    Published: 2020
    [Advance publication] Released: September 08, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The study investigated the effects of the modified conventional glass ionomer cement (GIC) incorporated with casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on biofilm composition of dental caries. Shear bond strength, durability tests, adhesive remnant index (ARI) and scanning electron microscope were used to measure the physical properties. Microhardness and ions release were determined to evaluate anti-demineralization effects; growth of the biofilm and its composition were assessed using MTT assay and Q-PCR assay. All experimental groups exhibited a significant stimulation of ions release, and reduced attenuation of microhardness. Nearly 39% reduction in the bacterial biofilm was observed with 5% CPP-ACP group. The regulation ability is mainly manifested in the inhibition of S. mutans and promotion of S. gordonii. The modified GICs by exhibiting anti-demineralization effects potentially lead to a reduction in the cariogenicity of plaque and can serve as a putative promising remineralization system with both enhanced antimicrobial and remineralization properties.

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  • Yuki ICHIOKA, Takashi KADO, Hideki AITA, Takashi NEZU, Yasushi FURUICH ...
    Type: research-article
    Article ID: 2019-358
    Published: 2020
    [Advance publication] Released: September 08, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    The aim of this study was to evaluate the NaOCl-mediated biofunctionalization of titanium surfaces. Titanium disks stored for 2 weeks were immersed in 5% NaOCl solution for 24 h. A disk immersed in distilled water for 24 h was used as a control. X-ray photoelectron spectrometer assay of the titanium surface after NaOCl treatment demonstrated that organic contaminants containing carbon and nitrogen were removed and the number of hydroxyl groups increased. The NaOCl treatment substantially converted the titanium surface to superhydrophilic status (θ<5°), which resulted in an increased number of attached cells and enhanced cell spreading on the NaOCl-treated surfaces. These results indicate that biofunctionalization of the biologically degraded titanium surfaces can be achieved by chemical surface treatment with 5% NaOCl. The mechanism for desorption of strongly adsorbed organic molecules with polar groups such as amino and aldehyde groups from titanium surfaces by ClO was elucidated.

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  • Alexander SCHMIDT, Peer SCHRADER, Kay FRENDEL, Maximiliane A. SCHLENZ ...
    Type: research-article
    Article ID: 2019-373
    Published: 2020
    [Advance publication] Released: September 08, 2020
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    As shown in previous studies within other scientific fields, the material behavior of polymethyl methacrylate (PMMA) is viscoelastic-viscoplastic. However, in dental biomaterial science it is mostly considered as linear elastic or elastic-plastic. The aim of the present study was to evaluate, whether the assumption of elastic or elastic-plastic material behavior for PMMA is a practicable simplification or a potential source of error, especially considering clinical loading conditions. Telio-CAD was tested in three-point bending tests with different test velocities to examine the material behavior at different initial loading rates. Additionally, a dynamic-mechanical-thermal-analysis at different frequencies and temperatures was used. Here, a significant influence of loading rate and temperature as well as stress relaxation and creep were observed. To describe the rate-dependency of the elastic modulus, a new model was created, from which the elastic modulus can be calculated with a given strain rate. This model was validated using linear elastic finite element analysis.

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