Dental Materials Journal
Online ISSN : 1881-1361
Print ISSN : 0287-4547
ISSN-L : 0287-4547
Current issue
Showing 1-23 articles out of 23 articles from the selected issue
Review
  • Takashi KOMABAYASHI, David COLMENAR, Nicholas CVACH, Aparna BHAT, Caro ...
    Type: review-article
    2020 Volume 39 Issue 5 Pages 703-720
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: March 24, 2020
    JOURNALS FREE ACCESS

    Endodontic sealers for non-surgical root canal treatment (NSRCT) span many compositions and attributes. This comprehensive review discusses current types of endodontic sealers by their setting reaction type, composition, and properties: zinc oxide-eugenol, salicylate, fatty acid, glass ionomer, silicone, epoxy resin, tricalcium silicate, and methacrylate resin sealers. Setting time, solubility, sealing ability, antimicrobial, biocompatibility, and cytotoxicity are all aspects key to the performance of endodontic sealers. Because sealing ability is so important to successful outcomes, the relative degree of microleakage among all the relevant sealers was calculated by way of a meta-analysis of relevant literature. Compared to AH Plus, tricalcium silicate sealers show the lowest relative microleakage among the sealers assessed, followed by silicone sealers and other non-AH Plus epoxy resin sealers. Tricalcium silicate sealers also exhibit the most favorable antimicrobial effect and excellent biocompatibility. Future sealers developed should ideally combine a hermetic seal with therapeutic effects.

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Original Paper
  • Takashi KAMEDA, Harumi SATO, Shunya OKA, Akiko MIYAZAKI, Kazuo OHKUMA, ...
    Type: research-article
    2020 Volume 39 Issue 5 Pages 721-734
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 19, 2020
    JOURNALS FREE ACCESS

    A strong esthetic demand exists for white-colored rather than metallic-colored dental appliances. Polytetrafluoroethylene (PTFE), which is chemically stable with extremely low friction, is a suitable white-colored coating for dental appliances. In the conventional PTFE coating process, base materials are heated to approximately 400°C, which could change their mechanical properties. Examination of the PTFE-coating of stainless steel, nickel titanium (Ni-Ti), and β-titanium (Ti-Mo and Ti-Nb) revealed that the conventional 380°C coating, but not the newly developed low temperature coating at 200°C, reduced elasticity and bendability, and changed the crystal structure, especially in Ni-Ti and Ti-Nb wires. PTFE-coating at 200°C resulted in less discoloration, microbial adhesion, and friction against brackets, and higher tolerance of wear than did the conventional 380°C coating. These results suggest that low temperature PTFE coating is an excellent method for improving the metallic appearance of orthodontic wires without changing their mechanical properties.

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  • Yoshio SHIMA, Kyoto TAKEMOTO, Akihiro KOYAMA, Motohiro UO, Takashi ONO
    2020 Volume 39 Issue 5 Pages 735-741
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 12, 2020
    JOURNALS FREE ACCESS

    The play between bracket slots and archwires affects tooth movement and the transmission of orthodontic force by multi-bracket appliances. We assessed play by quantifying the play behavior of three-point brackets and comparing the amount of play that occurred with square and rectangular slots, respectively, by using archwires of various sizes. Horizontal play with the square slot was significantly smaller than that with the rectangular slot. These data demonstrate that brackets with square slots can more effectively bring about tooth movement in the labio-lingual direction and control rotational movement with round and square archwires. Since the horizontal and vertical play ratios for the round and square wires within the square slot were approximately 1.0, three-dimensional tooth movement may also be achieved with uniform play in the vertical and horizontal directions.

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  • Yasushi HIBINO, Yuko NAGASAWA, Yoshikazu EDA, Hirotaka SHIGETA, Hirosh ...
    Type: research-article
    2020 Volume 39 Issue 5 Pages 742-751
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 16, 2020
    JOURNALS FREE ACCESS

    The objective of this study was to examine the effects of storage conditions on the flexural strengths of resin composite materials for CAD/CAM restorations. Seven commercially available resin composite CAD/CAM blanks were examined. Rectangular specimens (4.0×1.2×4.0 mm) of each material were trimmed from the blanks and subjected to thermal cycling between 5°C and 55°C in deionized water at 10,000 cycles or stored in 37°C deionized water for one week or air for one day (n=10 for each condition). The difference in storage condition between water immersion and thermal cycling did not affect the flexural strengths of resin composite materials for CAD/CAM examined in this study. The resin composite block CS300 made from Bis-MEPP and UDMA showed the greatest flexural strength under all storage conditions and less deterioration of strength by thermal cycling and water immersion among the resin composite blocks tested.

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  • Shunsuke AKAHANE, Hiroyasu KOIZUMI, Akihisa KODAIRA, Mitsuo NAKAMURA, ...
    Type: research-article
    2020 Volume 39 Issue 5 Pages 752-759
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 12, 2020
    JOURNALS FREE ACCESS

    The purpose of this study is to investigate the combined effect of two-liquid silane-phosphate primer and single-liquid sodium sulfite primer on bonding between self-polymerizing resins and feldspathic ceramics, and to promote the polymerization behavior of self-polymerizing resins at the bonding interface. The silane-phosphate primer (Super-Bond PZ Primer; PZ) and the sodium sulfite primer (Teeth Primer; TP) were used as the surface treatment agents for bonding the feldspathic ceramics and the self-polymerizing resins (MMA-TBB resin and 4-META/MMA-TBB resin). Combined PZ and TP showed high shear bond strengths. The peak of the differential scanning calorimetry curve was shown to occur early through the addition of TP. These results indicated that additional TP promoted the conversion in the initial polymerization of resin, and the firmly bond was obtained at the interface. PZ+TP treatment can be regarded as an effective treatment for a temporary splint used in teeth restoration.

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  • Masayuki NARUKAWA, Osamu SUZUKI, Mitsuori MAYAHARA, Eisaku IMAMURA, Yo ...
    Type: research-article
    2020 Volume 39 Issue 5 Pages 760-765
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 12, 2020
    JOURNALS FREE ACCESS

    Commercially available deproteinized cancellous bovine bone (DPBB) has been indicated as non-absorbable bone filling materials. Stoichiometric hydroxyapatite (HA) was not resorbed by osteoclasts while calcium-deficient and carbonate-rich apatite converted from octacalcium (OCP hydrolysate) was resorbed by osteoclasts. We analyzed the chemical composition of DPBB and compared the tissue reactions around two materials after implanting into mouse bone marrow. X-ray diffraction analysis and Fourier transform infrared spectroscopy showed that DPBB was a carbonate-rich apatite. Micro-CT analysis indicated the massive bone formation on both materials at 2 weeks, then gradually resorbed. At 12 weeks, osteoclasts were directly attached to both materials. The ultrastructure of ruffled borders on DPBB was identical to osteoclasts resorbing normal bone while ruffled border on OCP hydrolysate showed irregular shape. These results indicated that DPBB was the absorbed material and that the structure of ruffled border of osteoclasts might be regulated by the size or orientation of HA.

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  • Gangjae KIM, Byoung-Duck ROH, Sung-Ho PARK, Su-Jung SHIN, Yooseok SHIN
    Type: research-article
    2020 Volume 39 Issue 5 Pages 766-772
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 12, 2020
    JOURNALS FREE ACCESS

    The purpose of this study was to investigate whether tooth-brushing with a microcurrent was effective in inducing dentinal tubule occlusion. The specific aims of the study were (1) to evaluate the effectiveness of tooth-brushing with a microcurrent on dentinal tubule occlusion by using scanning electron microscopy (SEM); and (2) to compare the dentinal fluid flow rate after tooth-brushing with a microcurrent by using a sub-nanoliter-scaled fluid flow measuring device (NFMD). All experimental groups showed partially occluded dentinal tubules and crystal-like structures at a specific microcurrent intensity indicated that tooth-brushing with a microcurrent could efficiently occlude dentinal tubules. The decrease in dentinal fluid flow rate in the tooth-brushing with microcurrents group indicated that dentinal tubules were occluded and the flow of dentinal fluid had decreased.

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  • Alexandros NIKOLAIDIS, Triantafyllia VOUZARA, Elisabeth KOULAOUZIDOU
    Type: research-article
    2020 Volume 39 Issue 5 Pages 773-783
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: January 11, 2020
    JOURNALS FREE ACCESS

    The aim of the present work was to investigate the effect of the different organically modified nanoclays on clinically significant properties of new synthesized dental pit and fissure nanocomposite sealants. Their morphological characteristics were examined by means of X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). A universal testing machine was used to conduct the flexural and compression tests. Surface roughness measurements were taken by using a 3D-optical profilometer. Color changes after aging in black tea were determined by recording UV-visible spectra. XRD plots depicted possible structures governed by intercalated regions along with some “tactoids” nanoparticles. SEM images revealed a better dispersion for the methacrylated clay nanofiller. Flexural modulus and microhardness were found to be higher for sealants reinforced with such polymerizable nanoclays. These specific nanocomposites yielded smoother surfaces, as well as clinically accepted color changes even after 1 week aging in black tea.

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  • Toshinori OKAWA, Susumu ABE, Masanori NAKANO, Kenji OKA, Eriko HORIKAW ...
    Type: research-article
    2020 Volume 39 Issue 5 Pages 784-791
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 12, 2020
    JOURNALS FREE ACCESS

    The purpose of this study is to investigate the precision and trueness of the occlusal contact record obtained with a dental CAD/CAM device (ARCTICA). Sandblasted spherical steel balls with diameters of 10–20 mm were measured using ARCTICA and a three-dimensional measurement device (FN503). The radius of each steel ball was calculated from the measured value and the difference between the measured and nominal values was obtained. Upper/lower dental arch casts were measured and processed for occlusal contact image creation using both devices. The graphical images of the occlusal contacts at the intercuspal position obtained from both systems and an occlusal analysis device (BE-1) were compared with the occlusal contact area. Excellent correlation was observed between the measurement results of ARCTICA and FN503 (p<0.001, R2: 0.99). The occlusal contact areas were 186.0 mm2 (ARCTICA), 192.8 mm2 (FN503), and 196.1 mm2 (BE-1). This study showed that ARCTICA is capable of conducting highly accurate measurements and generating a graphical image of occlusal contacts with good reliability.

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  • Kaho ABE, Takashi ASANO, Masahiro AIDA, Norihiro NISHIYAMA, Osamu KOMI ...
    Type: research-article
    2020 Volume 39 Issue 5 Pages 792-802
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 16, 2020
    JOURNALS FREE ACCESS

    Resin-ceramic hybrid materials for computer-aided design/computer-aided manufacturing (CAD/CAM resins) have been developed. In this study, the effects of the amount of light energy transmitted through the four types of 1.5-mm-thick CAD/CAM resin blocks on the bond performance of corresponding resin cement adhesive systems consisting of an adhesive and a dual-curable resin cement were examined. The bond strengths of the four types of resin cement adhesive systems decreased with decreasing the amount of light energy transmitted through CAD/CAM resin block, due to a decrease in the light-curable ability of dual-curable resin cements. However, the degradation behavior of the bond strengths was strongly affected by the types of adhesives and initiator systems utilized. The adhesive consisting of a dimethacrylate monomer and redox-initiators enhanced the bonding performance of the dual-curable resin cement more effectively than the adhesive, which consists of a dimethacrylate monomer and photo-initiators or a γ-me thacryloxypropyltrimethoxysilane and a 10-methacryloyloxydecyl dihydrogen phosphate.

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  • Chunwoo LEE, Kana KASHIMA, Akiko ICHIKAWA, Satoshi YAMAGUCHI, Satoshi ...
    Type: research-article
    2020 Volume 39 Issue 5 Pages 803-807
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 12, 2020
    JOURNALS FREE ACCESS

    The aim of this study was to build an in silico computer-aided design and computer-aided manufacturing (CAD/CAM) resin-composite-block (RCB) model with different silane coupling ratios and to evaluate the physical and mechanical properties of the models, including the elastic modulus, Poisson’s ratio, compressive strength, and maximum principal strain. Nanoscale CAD/CAM RCB models were designed by using CAD software that consisted of twelve spherical silica nanofiller particles and a resin matrix. Seven nanoscale models with different silane coupling ratios were prepared with the same filler volume contents. Homogenization analysis was conducted by using voxel-base finite-element analysis software to predict the elastic moduli and Poisson’s ratio of the macro CAD/CAM RCB. Localization analysis was used to analyze the maximum principal strain distribution in the hydrolysis layer. In silico multi-scale analysis demonstrated that the compressive strength of the CAD/CAM RCB was reduced with a decrease in the silane coupling ratios of the fillers.

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  • Huanhuan JIANG, Wenjuan ZHOU, Binchen WANG, Liqin TANG
    Type: research-article
    2020 Volume 39 Issue 5 Pages 808-814
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 22, 2020
    JOURNALS FREE ACCESS

    It has been shown that strontium (Sr) promotes bone formation, reduces bone resorption. In the study, magnetron sputtering method was used for preparing Sr covered on sandblasted and acid-etched (SLA) titanium surface. Surface morphology was examined by scanning electron microscopy (SEM), chemical composition of surface was investigated by X-ray energy dispersive spectrometry (EDS). MC3T3-E1cells were cultured on Sr-SLA and SLA disks. Cell morphology was studied through confocal laser scanning microscope and SEM. Cell proliferation were measured by MTT assay. Degrees of mineralization and alkaline phosphatase (ALP) activity were calculated and compared. EDS and SEM results indicated that Sr ions were successfully loaded in Sr-SLA surface, whereas, Sr-SLA and SLA surfaces demonstrated similar typical isotropic irregular indentations. The MC3T3-E1 cells developed on Sr-SLA surface showed improved morphology, better proliferation as well as greater differentiation.These findings suggest that the modification with Sr incorporated in moderately rough surface has a favorable biocompatibility.

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  • Gülbike DEMIREL, Fatma Funda KAYA DEMIRSOY, Özgür IRMAK
    Type: research-article
    2020 Volume 39 Issue 5 Pages 815-824
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: June 06, 2020
    JOURNALS FREE ACCESS

    The aim of this study was to evaluate the cytotoxicity of universal adhesives on L929 mouse fibroblast cell line by using a real-time cell analysis. In order to obtain extract, six different cured dental adhesives were immersed in Dulbecco’s Modified Eagle’s Medium (DMEM) at 37°C for 24 h. A real-time cell analysis system was used to assess cytotoxicity of the dental adhesives. After seeding 25,000 cells/300 μL/well cell suspensions into the wells of an e-plate, fibroblasts were exposed to extracts of tested adhesives at varying dilutions (1:1, 1:2, and 1:10) and observed at every 30 min intervals for 72 h. Three-way ANOVA one factor repeated measures were used to analyze the results (α=0.05). All tested adhesives induced cell viability loss, cell morphology alteration, and cell death depending on extract concentration and time. Cell viability of L929 cells to between 44 and 10% for 1:1 diluted extracts, at 72 h, when compared to the negative control.

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  • Tomofumi SAWADA, Christine SCHILLE, Ernst SCHWEIZER, Jürgen GEIS-GERST ...
    Type: research-article
    2020 Volume 39 Issue 5 Pages 825-833
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 16, 2020
    JOURNALS FREE ACCESS

    This study evaluated bond strengths of three commercial veneering porcelains to experimental cast titanium-chromium (Ti-Cr) alloy and commercially pure titanium (cp-Ti) via three-point bending test. After the bending test, the fractured specimens were analyzed using an electron probe microanalyzer (EPMA). The Ti-Cr specimens showed lower bond strengths than the cp-Ti specimens, irrespective of the layering porcelain material; however, all the strengths exceeded the minimum requirement of ISO 9693-1:2012 (>25 MPa). EPMA revealed that titanium and/or chromium elements were detected on the debonded porcelain surface of the Ti-Cr and cp-Ti specimens in the case of the higher bond strength. Contrastingly, the residual porcelain was retained on the metallic surface in the case of the lower bond strength. Although porcelain bonding to the titanium alloy is influenced by porcelain type, the Ti-Cr alloy could be feasible for porcelain-fused-to-metal restorations.

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  • Nao TAKAHASHI, Chiaki YABUKI, Hiroyasu KUROKAWA, Toshiki TAKAMIZAWA, Y ...
    Type: research-article
    2020 Volume 39 Issue 5 Pages 834-843
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 19, 2020
    JOURNALS FREE ACCESS

    The aim of this study was to determine the influence of different surface treatments of CAD/CAM composite blocks on bonding effectiveness of resin cements, based on the shear bond strength test and the surface science examination. Specimens were fabricated from two types of CAD/CAM composite blocks (Cerasmart and VITA Enamic), and the specimen surfaces were alumina sandblasted. Specimen surfaces were treated with i) silane, ii) primer, and iii) silane+primer, then two types of cements (Block HC Cem and Super Bond) were bonded. After 24 h storage, bond strengths were measured. Surface free energy measurements were performed of the treated CAD/CAM composite blocks surfaces. The groups ii) and iii) showed significantly higher bond strengths than the group i), apart from VITA Enamic with Block HC Cem. Although the total surface free energy showed different trends in different surface treatments, a similar trend was found in both CAD/CAM composite blocks.

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  • Kou TSUKAGOSHI, Masatsugu HIROTA, Rie NOMOTO, Tohru HAYAKAWA
    Type: research-article
    2020 Volume 39 Issue 5 Pages 844-854
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 22, 2020
    JOURNALS FREE ACCESS

    The purposes of this study were to evaluate the shear bond strength and perform the computational analysis for silane coupling treatments on the adhesion between CAD/CAM composite resin and resin cement. As silane coupling agents, γ-methacryloyloxy propyltrimethoxysilane, 8-methacryloyloxyoctyl trimethoxysilane, and 3-methacryloyloxypropyl trichlorosilane were used. The shear bond strengths were influenced by the silane coupling agent used, its application method, and acid addition. There was no correlation between the contact angle and shear bond strengths. The steric energy difference between a silane coupling agent and its corresponding hydrolyzed trisilanol compound, ∆E, was calculated by the molecular mechanics method. There was a moderate or strong linear correlation between ∆E and shear bond strengths in treatment without acid addition and a weak correlation between them in treatment with acid addition. Computational analysis could suggest the different path of silane coupling treatments of CAD/CAM composite resin in the presence or absence of acid.

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  • Meng-Long HU, Gang ZHENG, Ruo-Dan JIANG, Jian-Ming HAN, You-Dong ZHANG ...
    Type: research-article
    2020 Volume 39 Issue 5 Pages 855-861
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 27, 2020
    JOURNALS FREE ACCESS

    This study was evaluating how three desensitizing toothpastes used at home influence the effect associated with desensitizing agents after application in the clinic. Fifty dentine disks measure it permeability and 32 dentine disks with similar permeability levels were selected. Following Dental desensitizer treatment, dentine disks were randomly divided into three subgroups (n=10) that received applications of three toothpastes, respectively. The permeability (Lp) of each specimen was measured after each treatment. One specimen was selected from each group for scanning electron microscopy (SEM) observation. After each treatment, the Lp values decreased significantly for each group (p<0.05) and either completely or partially blocked the dentine tubules upon SEM observation. However, no significant differences in Lp values were observed amongst subgroups (p>0.05). After using the Dental desensitizer, Sensodyne, Crest and Colgate desensitizing toothpastes both can continued to reduce the permeability of the dentine disk, and no significant differences were found amongst them.

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  • Yi-Fang LO, Vinay PITCHIKA, Nicoleta ILIE, Reinhard HICKEL, Jan KÜHNIS ...
    Type: research-article
    2020 Volume 39 Issue 5 Pages 862-868
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 27, 2020
    JOURNALS FREE ACCESS

    This in vitro study evaluated the shear bond strength (SBS), failure mode and microleakage of fissure sealing materials in relation to different etching times on aprismatic and prismatic enamel. Ninety-six healthy human third molars were randomly allocated to the following groups: 1) prismatic or aprismatic enamel; 2) etching: 15, 30, 45, 60 s. After 5,000-fold thermocycling SBS, failure mode and microleakage were measured. Statistical evaluation included Mann-Whitney-U-test and linear regression analysis. In the aprismatic enamel group, an increasing etching time resulted in higher SBS. The linear regression model revealed that 60 s of etching time led to a significant increase in SBS. Microleakage was found to be low in all test groups. This study indicated that 60 s of etching time showed to a significantly better SBS. When considering the small differences of SBS, failure modes and microleakage between 30 and 60 s etching time, 30 s acid etching seems to also be justifiable.

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  • Yuta MORIYA, Futoshi KOMINE, Junichi HONDA, Kosuke KUSABA, Jin KITANI, ...
    Type: research-article
    2020 Volume 39 Issue 5 Pages 869-876
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 22, 2020
    JOURNALS FREE ACCESS

    To investigate the effect of luting agent type on fracture loads of implant-supported ceramic prostheses in premolar region. Ninety-nine implant-abutment complexes were divided into three different implant-supported prostheses: monolithic yttria-partially stabilized zirconia (Y-PSZ) restorations (MPZ specimens), porcelain layered on yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) restorations (PLZ specimens), and monolithic lithium disilicate ceramic restorations (MLD specimens). Implant-supported prostheses were luted with adhesive resin luting agent (RLA), glass ionomer cement (GIC), or zinc phosphate cement (ZPC). For MPZ and MLD specimens, fracture loads were significantly higher for RLA group than for GIC and ZPC groups. For PLZ specimens, fracture loads did not significantly differ in relation to luting agent. Fracture loads were significantly higher for MPZ specimens than for other test specimens, regardless of luting agent. Use of an adhesive resin luting agent is recommended for placement of premolar implant-supported monolithic Y-PSZ and lithium disilicate ceramic prostheses.

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  • Hanako UMEHARA, Kazuya DOI, Yoshifumi OKI, Reiko KOBATAKE, Yusuke MAKI ...
    Type: research-article
    2020 Volume 39 Issue 5 Pages 877-882
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 22, 2020
    JOURNALS FREE ACCESS

    This study evaluates a bioactive titanium membrane with alkali treatment for stimulating apatite formation and promoting bone regeneration. The titanium thin membranes were either treated with NaOH (alkali-group) or untreated (control). Each sample were incubated in simulated body fluid. Subsequently, the composition of the surface calcium deposition, its weight increase ratio, and optical absorbance were evaluated. Then, the bone defect was trephined on the rats calvaria and covered with each sample membrane or no membrane, and the bone tissue area ratio (BTA) and bone membrane contact ratio (BMC) were evaluated. The spherical crystalline precipitates formed in both groups. In the alkali-group after 21 days, the precipitates matured, forming apatite-like precipitates. The alkali-group showed higher Ca and P contents and weight increase ratios than the control. The alkali-group exhibited a higher BMC than the control in the central area. Thus, this novel membrane has high apatite-forming and bone regeneration abilities.

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  • Kaori TSUCHIYA, Ryo HAMAI, Susumu SAKAI, Osamu SUZUKI
    Type: research-article
    2020 Volume 39 Issue 5 Pages 883-891
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 22, 2020
    JOURNALS FREE ACCESS

    This study compared bovine serum albumin (BSA) adsorption onto octacalcium phosphate (OCP) materials prepared from two wet preparations in the absence (w-OCP) and presence (c-OCP) of gelatin. Raman spectroscopy was used to analyze the BSA adsorption onto OCPs in a 150 mM Tris-HCl buffer containing 0.5 mM calcium and inorganic phosphate (Pi) ions at pH 7.4 and at 37°C. The degree of supersaturation of the supernatants after the adsorption was determined by measuring the ion composition. The results showed that BSA adsorption onto w-OCP was higher than that for c-OCP. The calcium ion concentration of the supernatant decreased for both w-OCP and c-OCP, whereas the Pi ion concentration increased, approaching OCP equilibria at different saturation levels. BSA adsorbed even onto c-OCP, which included a small amount of gelatin during c-OCP preparation. These results indicate that the biodegradability of w-OCP and c-OCP may be modulated through interactions with serum proteins.

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  • Kazuhide YONEKURA, Keiichi HOSAKA, Antonin TICHY, Keita TAGUCHI, Masao ...
    Type: research-article
    2020 Volume 39 Issue 5 Pages 892-899
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: May 22, 2020
    JOURNALS FREE ACCESS

    The effect of different air-blowing strategies using a prototype of a newly developed clinically applicable warm air-blowing device on the microtensile bond strength (μTBS) of one-step self-etch adhesives (1-SEAs) to human root-canal dentin was evaluated. Post cavities (8 mm depth, 1.5 mm diameter) were prepared and bonded with four 1-SEAs. Air-blowing was performed using normal air (23±1°C) for 10 or 20 s; warm air (60±1°C) for 10 or 20 s; or their combination for 10 s (5 s normal, 5 s warm) or 20 s (10 s normal, 10 s warm). After filling with corresponding core materials and 24-h water storage, μTBS test was performed. For three of the 1-SEAs, combined air-blowing for 20 s significantly increased μTBS compared to other air-blowing strategies (p<0.05). This suggests that the combination of normal and warm air-blowing for 20 s can enhance solvent evaporation from 1-SEAs, thus resulting in their improved bonding performance to root-canal dentin.

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  • Longzhao KANG, Yan ZHOU, Jinle LAN, Yunhua YU, Qing CAI, Xiaoping YANG
    Type: research-article
    2020 Volume 39 Issue 5 Pages 900-908
    Published: September 28, 2020
    Released: September 29, 2020
    [Advance publication] Released: July 02, 2020
    JOURNALS FREE ACCESS

    This study intends to obtain a kind of polymer-infiltrated ceramic-network (PICN) composite with improved performance for dental restoration. Porous ceramic network was prepared via compressing feldspar powders, followed by resin infiltration using Bis-GMA/TEGDMA or UDMA/TEGDMA mixtures to obtain PICN composites after thermocuring. The sintering parameters (temperature, duration) for the formation of feldspathic network with proper porosity were investigated. The ratios of resin mixtures were adjusted to optimize the infiltration. Comprehensive characterizations were conducted on the porosity and the shrinkage of preformed ceramic-networks, the viscosity of resin mixtures and their infiltration into the ceramic networks, as well as, flexural properties, Vickers hardness and wear resistance of the final PICN composites. It turned out that the PICN composite prepared from Bis-GMA/TEGDMA (6:4) achieved the best performance among all the samples, which is expected to be a suitable material for computer-aided design/computer-aided manufacturing (CAD/CAM) dental restorative applications.

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