Kagoshima University · Medical Care Center

Research keywords抗菌性ジルコニア・ランタノイド錯体・銀担持ジルコニア・歯科用材料開発・接着歯学

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• NISHITANI Yoshihiro, KURAHASHI Naoya, HEIMA Masahiro, MIURA Koki, ITOTAGAWA Mihiro, SHIRAOGAWA Takahiko, SAKANOUE Yoshinori, TSUTSUMI Sadami . Application of Terahertz Waves for Dental Treatme2022 · 記述言語： 英語 出版者・発行元： Japanese Association of Regenerative Dentistry <p>The terahertz wave, which is expected to be used in the future medical field, was examined for the possibility of being applied to conservative pulp treatment. For example, in order to avoid pulpectomy in the deep caries treatment, it is extremely useful to detect the remaining amount of carious dentin and the distance to the pulp in the cavity. As a pilot study of application to dental treatment, the propagation velocity of terahertz waves in enamel and dentin was measured. As controls, natural single crystal of apatite and HIP-treated powder apatite were also measured. As a result, enamel and dentin had different propagation velocities. It suggests that not only enamel and dentin in the oral cavity but also sound dentin and carious dentin with different calcification degrees can be identified by terahertz waves because the propagation rate increases depending on the density of apatite in the sample.</p> DOI： 10.11223/jarde.19.15 CiNii Research
• Nishitani Yoshihiro, Kurahashi Naoya, Heima Masahiro, Miura Koki, Itotagawa Mihiro, Shiraogawa Takahiko, Sakanoue Yoshinori, Tsutsumi Sadami2021 · 記述言語： 英語 出版者・発行元： 日本再生歯科医学会
• Itotagawa M., Kono H., Higashinakao T., Sugiura Y., Otsuka Y., Kikuchi M., Nishitani Y. . Adsorption of oral antibacterial agents on zirconia surfaces with different crystal systems .2017 · 担当区分： 筆頭著者 記述言語： 日本語 出版者・発行元： RSC Advances Zirconia ceramics are widely used as dental prosthetics owing to their high biocompatibility, excellent mechanical strength, and aesthetic properties similar to color tones of natural teeth. However, there exists a growing demand for the facile attachment of antibacterial properties in long-term dental restoration. Thus, in this study, we evaluated the adsorption ability of cetylpyridinium chloride (CPC) and benzalkonium chloride (BKC)—quaternary amines widely used as antibacterial substances in commercial toothpaste and other oral care products—onto zirconia surfaces with tetragonal and monoclinic crystal structures. Although tetragonal zirconia has been widely used in dental prosthetic materials such as crowns etc., monoclinic zirconia has also been used under oral conditions because of long-term implantation. When antibacterial molecule loading on zirconia powders under simulated oral conditions, it was revealed that monoclinic zirconia adsorbed approximately five times more CPC and BKC per unit area compared with that of tetragonal zirconia. Moreover, in tetragonal zirconia, the adsorption amounts of both CPC and BKC increased slightly with growing Y2O3 content as a stabilizer. This phenomenon was attributable to the formation of complexes between rare earth elements (REE) such as Y2O3 in zirconia and quaternary amines such as CPC and BKC. In this study, the antibacterial molecular adsorption ability of dental zirconia was observed, and new advantages of zirconia in dental applications were discovered. DOI： 10.1039/d4ra04084h Scopus PubMed
• Higashinakao T., Kono H., Itotagawa M., Sugiura Y., Otsuka Y., Kikuchi M. . Preparation and antibacterial evaluation of silver-doped zirconia for enhanced dental restoration performance2013 · 記述言語： 日本語 出版者・発行元： Biomedical Materials (Bristol) Because of its superior strength, esthetic properties, and excellent biocompatibility, zirconia is preferred for dental prosthetic such as crowns and bridges. However, zirconia crowns and bridges are susceptible to secondary caries owing to margin leakage. Silver is a well-known antibacterial agent, making it a desirable additive to zirconia crowns and bridges for secondary caries prevention. This study focuses on imparting zirconia composite with antibacterial properties to enhance its protective capacity in dental restorations. We used the sol-gel method to dope Ag into zirconia. Silver-doped zirconia powders were prepared at Zr:Ag molar ratios of 100:0,100:0.1, 100:0.5, 100:1, 100:3, and 100:5 (respective samples denoted as Ag-0, Ag-0.1, Ag-0.5, Ag-1, Ag-3, and Ag-5) and were subjected to firing at various temperatures (400 °C-1000 °C). We performed x-ray diffraction to investigate the crystal phase of these powders and x-ray fluorescence and field emission scanning electron microscopy to analyze their elemental composition and surface morphology, respectively. Moreover, we performed spectrophotometry to determine the L*a*b* color values, conducted dissolution tests, and quantified the Ag content through inductively coupled plasma optical emission spectroscopy. In addition, we studied the antibacterial activity of the samples. Analyses of the samples fired at ⩽600 °C revealed a predominantly white to grayish-white coloration and a tetragonal crystal phase. Firing at ⩾700 °C resulted in gray or dark gray coloration and a monoclinic crystal phase. The Ag content decreased after firing at 900 °C or 1000 °C. Ag-0.5 and above exhibited antibacterial activity against both Escherichia coli and Staphylococcus aureus. Therefore, the minimum effective silver-doped zirconia sample was found to be Ag-0.5. This study allows the exploration of the antimicrobial potential of silver-doped zirconia materials in dental applications such as prosthdontical lining materials, promoting the development of innovative restorations with protective capacity against secondary caries. DOI： 10.1088/1748-605X/ad6ac3 Scopus PubMed

• ランタノイドの錯体反応を応用した抗菌性ジルコニアフィラーの開発2026 · 担当区分： 研究代表者 配分額： 4290000円 （ 直接経費： 3300000円 、 間接経費： 990000円 ）
• 抗菌分子とランタノイドの錯体形成を利用した新規抗菌性ジルコニアフィラーの開発2023 · 担当区分： 研究代表者 配分額： 4680000円 （ 直接経費： 3600000円 、 間接経費： 1080000円 ）

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