Updated on 2021/12/27


Faculty of Medicine, Dentistry and Pharmaceutical Sciences Assistant Professor
Assistant Professor
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  • 博士(歯学) ( 岡山大学 )

Research Interests

  • 齲蝕学

  • 歯周病学

  • 口腔細菌

Research Areas

  • Life Science / Conservative dentistry

Professional Memberships



  • Use of Highly Accurate Devices for a First Lower Premolar Endodontic Treatment with Multiple Root Canals.

    Zulema Arias Martinez, Jorge Lopez Videla, Keisuke Yamashiro, Yuki Shinoda-Ito, Tadashi Yamamoto, Shogo Takashiba

    Acta medica Okayama   75 ( 5 )   641 - 645   2021

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    This case report highlights the importance of using a dental operating microscope (DOM) and ultrasonic endodontic tips (UETs) to locate all root canals in the lower first premolar. A 53-year-old woman presented to our clinic with pain in the lower right first premolar. After a detailed search using a DOM and UETs, three root canals were found, prepared with rotary HyFlex endodontic files, and obturated using the lateral condensation technique. At the five-year follow-up after treatment, the tooth was completely restored and fulfilling its function, with no signs or symptoms of any post-treatment flare-up.

    DOI: 10.18926/AMO/62778



  • Functionalized Graphene Oxide Shields Tooth Dentin from Decalcification. International journal

    M Z I Nizami, Y Nishina, T Yamamoto, Y Shinoda-Ito, S Takashiba

    Journal of dental research   99 ( 2 )   182 - 188   2020.2

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    Language:English   Publishing type:Research paper (scientific journal)  

    This in vitro study assessed the efficacy of functionalized graphene oxide (f-GO) nanocomposites on the decalcification of dentin, because dental caries of the root surface is becoming one of the new problems in aged society. Hydroxyapatite plates (HAP) and dentin slices were coated with f-GO nanocomposites by comparing them to silver diamine fluoride as a positive control, then treated with decalcification solutions such as ethylenediaminetetraacetic acid and citrate at 37°C for 24 h. Scanning electron microscopy (SEM) revealed significant protection of the surface morphology of HAP and dentin. On the other hand, a cariogenic Streptococcus mutans growth was inhibited by f-GO nanocomposites. In addition, cytotoxicity of them to epithelial cells was much less than that of povidone-iodine, which is commonly used for oral disinfectant. We synthesized 5 different f-GO nanocomposites such as GO-silver (Ag), GO-Ag-calcium fluoride (CaF2), GO-CaF2, GO-zinc, and GO-tricalcium phosphate (Ca3(PO4)2). They were standardized by evaluating under SEM, transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetry analysis (TGA), and Raman spectra after being synthesized in an aseptic technique. The abilities of GO-Ag, GO-Ag-CaF2, and GO-CaF2 nanocomposites were most preventive for decalcification. In addition, GO-Ag and GO-Ag-CaF2 almost completely inhibited S. mutans growth. However, they did not exhibit cytotoxicity to epithelial cells except at the highest concentration (0.1 w/v%) of GO-Ag and GO-Ag-CaF2. Furthermore, these f-GO nanocomposites exhibited less or no discoloration of dentin, although commonly used silver diamine fluoride causes discoloration of dentin to black. Thus, these f-GO nanocomposites are useful to protect dental caries on the tooth root that becomes a social problem in aged society.

    DOI: 10.1177/0022034519894583



  • Antimicrobial and antibiofilm effects of abietic acid on cariogenic Streptococcus mutans.

    Yuki Ito, Takashi Ito, Keisuke Yamashiro, Fumi Mineshiba, Kimito Hirai, Kazuhiro Omori, Tadashi Yamamoto, Shogo Takashiba

    Odontology   108 ( 1 )   57 - 65   2020.1

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    Language:English   Publishing type:Research paper (scientific journal)  

    Dental caries is a type of oral microbiome dysbiosis and biofilm infection that affects oral and systemic conditions. For healthy life expectancy, natural bacteriostatic products are ideal for daily and lifetime use as anti-oral infection agents. This study aimed to evaluate the inhibitory effects of abietic acid, a diterpene derived from pine rosin, on the in vitro growth of cariogenic bacterial species, Streptococcus mutans. The effective minimum inhibitory concentration of abietic acid was determined through observation of S. mutans growth, acidification, and biofilm formation. The inhibitory effects of abietic acid on the bacterial membrane were investigated through the use of in situ viability analysis and scanning electron microscopic analysis. Cytotoxicity of abietic acid was also examined in the context of several human cell lines using tetrazolium reduction assay. Abietic acid was found to inhibit key bacterial growth hallmarks such as colony forming ability, adenosine triphosphate activity (both planktonic and biofilm), acid production, and biofilm formation. Abietic acid was identified as bacteriostatic, and this compound caused minimal damage to the bacterial membrane. This action was different from that of povidone-iodine or cetylpyridinium chloride. Additionally, abietic acid was significantly less cytotoxic compared to povidone-iodine, and it exerted lower toxicity towards epithelial cells and fibroblasts compared to that against monocytic cells. These data suggest that abietic acid may prove useful as an antibacterial and antibiofilm agent for controlling S. mutans infection.

    DOI: 10.1007/s10266-019-00456-0



  • Effects of Lectins on initial attachment of cariogenic Streptococcus mutans. International journal

    Takashi Ito, Yasuhiro Yoshida, Yasuyoshi Shiota, Yuki Ito, Tadashi Yamamoto, Shogo Takashiba

    Glycoconjugate journal   35 ( 1 )   41 - 51   2018.2

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    Language:English   Publishing type:Research paper (scientific journal)  

    Oral bacteria initiate biofilm formation by attaching to tooth surfaces via an interaction of a lectin-like bacterial protein with carbohydrate chains on the pellicle. This study aimed to find naturally derived lectins that inhibit the initial attachment of a cariogenic bacterial species, Streptococcus mutans (S. mutans), to carbohydrate chains in saliva in vitro. Seventy kinds of lectins were screened for candidate motifs that inhibit the attachment of S. mutans ATCC 25175 to a saliva-coated culture plate. The inhibitory effect of the lectins on attachment of the S. mutans to the plates was quantified by crystal violet staining, and the biofilm was observed under a scanning electron microscope (SEM). Surface plasmon resonance (SPR) analysis was performed to examine the binding of S. mutans to carbohydrate chains and the binding of candidate lectins to carbohydrate chains, respectively. Moreover, binding assay between the biotinylated-lectins and the saliva components was conducted to measure the lectin binding. Lectins recognizing a salivary carbohydrate chain, Galβ1-3GalNAc, inhibited the binding of S. mutans to the plate. In particular, Agaricus bisporus agglutinin (ABA) markedly inhibited the binding. This inhibition was confirmed by SEM observation. SPR analysis indicated that S. mutans strongly binds to Galβ1-3GalNAc, and ABA binds to Galβ1-3GalNAc. Finally, the biotinylated Galβ1-3GalNAc-binding lectins including ABA demonstrated marked binding to the saliva components. These results suggest that ABA lectin inhibited the attachment of S. mutans to Galβ1-3GalNAc in saliva and ABA can be useful as a potent inhibitor for initial attachment of oral bacteria and biofilm formation.

    DOI: 10.1007/s10719-017-9795-2




  • Control on Contamination in Dental Unit Water Lines (DUWL) using Neutral Electrolyzed Water

    伊東(信田)有希, 大森一弘, 伊東孝, 大久保圭祐, 平井公人, 山本直史, 高柴正悟

    日本歯科保存学会学術大会プログラムおよび講演抄録集(Web)   155th   2021

  • Endodontic Management of a Mandible Premolar with 3 root canals-A Case Report-

    ROSALIA Arias Martinez Zulema, YAMASHIRO Keisuke, SHINODA-ITO Yuki, YAMAMOTO Tadashi, TAKASHIBA Shogo

    日本歯科保存学会学術大会プログラムおよび講演抄録集(Web)   152nd   2020

  • Functionalized Graphene Oxide Nanoparticles Protect Tooth Dentin from Decalcification besides Bactericidal Activity.

    ISLAM Nizami Mohammed Zahedul, NISHINA Yuta, YAMAMOTO Tadashi, SHINODA-ITO Yuki, TAKASHIBA Shogo

    日本歯科保存学会学術大会プログラムおよび講演抄録集(Web)   151st   2019

  • 広汎型中等度慢性歯周炎患者に対して衛生管理しやすい口腔内環境を確立した症例

    田村仁美, 清水明美, 伊東孝, 伊東有希, 河野隆幸, 高柴正悟

    日本歯周病学会会誌(Web)   61   2019

  • Endodontic Management of a Bucco-Accessory Root Canal of a Maxillary Central Incisor: A Case Report

    ROSALIA Arias Martinez Zulema, SIDDIQUI Yasir Dilshad, YAMASHIRO Keisuke, SHINODA-ITO Yuki, YAMAMOTO Tadashi, TAKASHIBA Shogo

    日本歯科保存学会学術大会プログラムおよび講演抄録集(Web)   151st   2019

  • 歯周病原細菌によるヒトと伴侶動物イヌとの人獣共通感染症検査の研究

    田井真砂子, 伊東孝, 平山晴子, 矢田範夫, 小川寛人, 田村和也, 伊東有希, 大久保圭祐, 伊東昌洋, 中村心, 岡本憲太郎, 平井公人, 山城圭介, 大森一弘, 山本直史, 樅木勝巳, 高柴正悟

    日本歯周病学会会誌(Web)   60   2018

  • 新規除鉄剤スーパーポリフェノール(SP)を応用した口腔感染制御システムの開発

    伊東有希, 大森一弘, 大原利章, 高柴正悟

    日本鉄バイオサイエンス学会学術集会プログラム・抄録集   41st   2017

  • 口腔バイオフィルム抑制に資する天然物質 松樹脂由来アビエチン酸の効果

    信田 有希

    岡山歯学会雑誌   35 ( 1 )   1 - 11   2016.6

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    Language:Japanese   Publisher:岡山歯学会  

    Streptococcus mutansの浮遊細菌とバイオフィルム形成菌に対するアビエチン酸の抗菌作用を検討した。アビエチン酸処理1時間後のS.mutans浮遊細菌またはS.mutansバイオフィルム中の細菌を平板塗布法により培養した結果、生菌数はアビエチン酸濃度依存的に減少し、浮遊細菌の最小発育阻止濃度は16μg/mLであった。アビエチン酸処理1時間後のS.mutans菌体表面は走査型電子顕微鏡観察上粗造であり、また16μg/mL以上のアビエチン酸処理S.mutansでは細胞壁に損傷を受けていたが、一方で64μg/mLのアビエチン酸処理細菌では一定のATP活性が継続して測定された。アビエチン酸はヒト上皮系細胞・ヒト由来歯肉線維芽細胞に対しては256μg/mL以上で、ヒト単球系細胞に対しては64μg/mLで細胞障害性を有していた。アビエチン酸がS.mutansに対して浮遊細菌の増殖抑制作用およびバイオフィルム形成菌の増殖抑制作用を有することが示唆された。


  • ナノバブル水の抗バイオフィルム効果の検討

    平井公人, 田口裕子, 信田有希, 峯柴史, 石井美和, 岡徹, 前田博史, 高柴正悟

    日本歯科保存学会学術大会プログラムおよび講演抄録集(Web)   139th   2013

  • アビエチン酸およびネオアビエチン酸の口腔細菌への抗菌効果

    信田有希, 山城圭介, 峯柴史, 平井公人, 前田博史, 高柴正悟

    日本歯周病学会学術大会プログラムおよび講演抄録集   55th   2012

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  • 歯科ユニット給水管路(DUWL)内汚染の実際と電解機能水の効果

    上田 彩華, 伊東-信田 有希, 大森 一弘, 伊東 孝, 大久保 圭祐, 平井 公人, 山本 直史, 高柴 正悟

    岡山歯学会学術大会  2021.11.28 

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  • Functionalized Graphene Oxide Nanocomposites Protect Decalcification of Hydroxyapatite and Dentin

    Nizami Mohammed Zahedul , Nishina Yuta , Yamamoto Tadashi , Shinoda-ito Yuki , Takashiba Shogo

    2020 IADR/AADR/CADR General Session (Washington, D.C., USA)  2020 

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  • Functionalized Graphene Oxide Nanocomposites Prevent Tooth Dentin Decalcification



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  • Natural Products for Prevention of Oral Biofilm: Effects of Abietic Acid

    Ito Yuki , Ito Takashi , Mineshiba Fumi , Hirai Kimito , Yamashiro Keisuke , Omori Kazuhiro , Maeda Hiroshi , Takashiba Shogo

    2015 IADR Japanese Division Meeting (Fukuoka, Japan)  2015 

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  • Pine-derived Abietic Acid as a Regulating Agent for Biofilm

    Shinoda-ito Yuki, Ito Takashi, Nakagiri-mineshiba Fumi, Hirai Kimito, Yamashiro Keisuke, Maeda Hiroshi, Takashiba Shogo


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  • 2021 IADR/AADR William J. Gies Award in Biomaterials and Bioengineering Research

    2021.7   International Association for Dental Research   "Functionalized Graphene Oxide Shields Tooth Dentin from Decalcification" in Journal of Dental Research, 2020 Feb;99(2):182-188.

    MZI Nizami, Y Nishina, T Yamamoto, Y Shinoda-Ito, S Takashiba

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Research Projects

  • 天然由来レクチンを用いた唾液アミラーゼ糖結合性の探索と解明

    Grant number:21K16946  2021.04 - 2023.03

    日本学術振興会  科学研究費助成事業 若手研究  若手研究

    伊東 有希

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    Grant amount:\4680000 ( Direct expense: \3600000 、 Indirect expense:\1080000 )


  • 新規口腔バイオフィルム感染制御法の基盤となる鉄キレート抗菌作用機序の解明

    Grant number:19K18961  2019.04 - 2021.03

    日本学術振興会  科学研究費助成事業 若手研究  若手研究

    伊東 有希

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    Grant amount:\4290000 ( Direct expense: \3300000 、 Indirect expense:\990000 )

    口腔バイオフィルム構成菌種のうちStreptococcus mutans(Sm)及びAggregatibacter actinomycetemcomitansを用いて液体培地中の濁度測定を行い,各種SPの抗菌スペクトルを把握したところ,特にSP6とSP10で抗菌効果が高い(300μg/ml以上)ことがわかった。そこでSP6とSP10を主なターゲットにしてSmバイオフィルム形成抑制効果の検討,グラム染色とLIVE/DEAD染色液を用いたSmの形態観察を行ったところ,SPは静菌的に細菌に作用しバイオフィルムに対しても概ね300μg/ml程度で抑制効果があることがわかった。
    ヒト由来歯肉線維芽細胞に対するSP6とSP10の細胞障害性をMTSアッセイを用いて検証したところ,300μg/ml程度でもin vitroでは細胞障害性を有することが判明した。



Class subject in charge

  • Clinical training:Pathophysiology of Oral Infection and Inflammation (2021academic year) special  - その他

  • Lecture and Research Projects:Pathophysiology of Oral Infection and Inflammation (2021academic year) special  - その他

  • Research Projects and Practice: Periodontal Science I (2021academic year) special  - その他

  • Lecture and Research Projects: Periodontal Science I (2021academic year) special  - その他

  • Research Projects and Practice: Periodontal Science II (2021academic year) special  - その他

  • Lecture and Research Projects: Periodontal Science II (2021academic year) special  - その他

  • Clinical training:Specialty Training for Advanced Periodontics (2021academic year) special  - その他

  • Lecture and Research Projects:Specialty Training for Advanced Periodontics (2021academic year) special  - その他

  • Clinical training:Specialty Training for Advanced Endodontics (2021academic year) special  - その他

  • Lecture and Research Projects:Specialty Training for Endodontics (2021academic year) special  - その他

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