{"created":"2021-03-01T06:30:53.734698+00:00","id":25428,"links":{},"metadata":{"_buckets":{"deposit":"a0cb6c4d-f777-4e2a-8f0f-38d0bc111dc7"},"_deposit":{"id":"25428","owners":[],"pid":{"revision_id":0,"type":"depid","value":"25428"},"status":"published"},"_oai":{"id":"oai:niigata-u.repo.nii.ac.jp:00025428","sets":["432:1291:1292:1297","453:456"]},"item_7_alternative_title_1":{"attribute_name":"その他のタイトル","attribute_value_mlt":[{"subitem_alternative_title":"Estimation of the corrosion resistance of anodized Ni-Ti orthodontic wires in acidic solutions containing fluoride"}]},"item_7_biblio_info_6":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"2010-12","bibliographicIssueDateType":"Issued"},"bibliographicIssueNumber":"2","bibliographicPageEnd":"141","bibliographicPageStart":"131","bibliographicVolumeNumber":"40","bibliographic_titles":[{"bibliographic_title":"新潟歯学会雑誌"},{"bibliographic_title":"新潟歯学会雑誌","bibliographic_titleLang":"en"}]}]},"item_7_description_4":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"歯列矯正用ワイヤとして用いられるNi-Ti合金は，超弾性の性質を持ち，大気中でTiO_2を主成分とする薄く安定な酸化被膜を表面に生成するため，極めて良好な耐食性を示す。しかし，う蝕予防薬などに含まれるフッ化物からF^-イオンが生成し，H^+イオンと結合してHF分子が形成されると，酸化被膜の溶解が起こる。特に，強い酸性環境では酸化被膜の溶解が促進し，下地合金からTiとNiが溶出する。溶出したNiによる有害作用として，細胞毒性，アレルギー，発癌性などが知られており，Ni溶出を減少することが強く望まれる。本研究の目的は，市販のNi-Ti矯正用ワイヤを酸性またはアルカリ性電解液中にて陽極酸化し，それら試料をF^-イオン含有の酸性溶液中に浸漬し，陽極酸化による表面改質の効果，つまり，Ni溶出量の減少を確認することである。市販のNi-Ti矯正用ワイヤを長さ20mmに切断し，試料とした。陽極酸化は，0.008mol/L H_2SO_4または0.030mol/L NaOHを電解液として用い，室温にて，直流10Vで，300秒間通電して行った。溶出試験は，入手のままと陽極酸化した試料を1,000ppmのNaFを含むpH 3.6またはpH 4.4の腐食溶液中に，37℃で，１時間浸漬して行った。腐食溶液中に溶出したTiとNiは，誘導結合プラズマ質量分析装置（ICP-MS）を用いて定量した。溶出試験前後の各試料の酸化被膜の厚さと組成は，X線光電子分光法（XPS）を用い，デプスプロファイルにより検討した。陽極酸化時の電流密度は，どちらの電解液を用いた場合も，平均値は1.3mA/mm^2であった。各試料の酸化被膜厚さは，入手のまま：4.0±0.5nm，H_2SO_4中で陽極酸化：33.3±1.5nm，NaOH中で陽極酸化：8.3±0.8nmであった。また，陽極酸化によって生成した酸化被膜の主成分は，TiO_2であった。各試料からのNi溶出量は以下のようになった。pH 3.6の腐食溶液への浸漬では，入手のまま：24.3±1.3μg/cm^2，H_2SO_4中で陽極酸化：19.1±1.7μg/cm^2, NaOH中で陽極酸化：26.7±0.1μg/cm^2であった。また，pH 4.4の腐食溶液への浸漬では，入手のまま：6.5±0.7μg/cm^2，H_2SO_4 中で陽極酸化：2.7±1.4μg/cm^2，NaOH中で陽極酸化：7.6±0.5μg/cm^2であった。すなわち，H_2SO_4中で陽極酸化した試料は，NaOHを用いた場合よりも，酸化被膜が厚く生成され，その結果，pH 4.4では，Ni溶出量は入手のままの場合の約40％に減少した。これらの結果，陽極酸化を適切に行えば，HF分子の存在する腐食溶液中でも，Ni-Ti矯正用ワイヤからのNi溶出量を少なくできることが確認された。","subitem_description_type":"Abstract"},{"subitem_description":"Ni-Ti alloy used as an orthodontic arch wire has super-elasticity and shows excellent corrosion resistance due to the thin oxide layer of TiO_2  formed in the atmosphere. However, dissolution of the oxide layer occurs when HF molecule is formed from H^+ ion and F^- ion which is contained in dental caries prophylactics. In particular, an oxide layer breaks in strong acidic environment and as a result both Ti and Ni elute from the alloy. As adverse effect by the dissolved Ni, cytotoxicity, allergy, and carcinogenicity are known, and accordingly decrease of the amount of Ni dissolution is strongly desired. The aim of this study is to confirm decrease of the amount of Ni dissolution by the surface treatment of anodic oxidation. Therefore, the electrochemical treatment of the commercial Ni-Ti orthodontic wires in acid or alkaline electrolyte was carried out and dissolution test of treated wires was done in acid solution containing F^- ion. Commercially available Ni-Ti orthodontic wires were cut into the pieces of 20 mm in length as specimens. In an aqueous solution of 0.008 mol/L H_2SO_4 or 0.030 mol/L NaOH as electrolyte, the anodic oxidation of the specimens was carried out for 300 s at applied voltage of 10 VDC at room temperature. Each specimen, as received, anodized in H_2SO_4 or anodized in NaOH, was dipped at 37℃ for 1 hour into one of two corrosive solutions, pH 3.6 or pH 4.4, which contained 1,000 ppm of NaF. The inductively-coupled plasma mass spectrometer (ICP-MS) was used to determine the amounts of Ti and Ni that were eluted from the specimens into the corrosive solutions. Before and after the dissolution tests, the chemical composition of oxide films and thickness of them were estimated from the depth profiles performed by the X-ray photoelectron spectroscopy (XPS). The mean values of current density at anodizing treatment were 1.3 mA/mm^2 regardless of the electrolyte. Each thickness of oxide films was as follows; 4.0±0.5 nm (as received), 33.3±1.5 nm (anodized in H_2SO_4), and 8.3±0.8 nm (anodized in NaOH). The main component of the oxide films generated by anodic oxidation was TiO_2. In the case of the solution of pH 3.6, each amount of Ni dissolution was as follows; 24.3±1.3 μg/cm^2 (as received), 19.1±1.7 μg/cm^2 (anodized in H_2SO_4), and 26.7 ±0.1 μg/cm^2 (anodized in NaOH). In the case of the solution of pH 4.4, each was as follows; 6.5±0.7 μg/cm^2 (as received), 2.7±1.4 μg/cm^2 (anodized in H_2SO_4), and 7.6±0.5 μg/cm^2 (anodized in NaOH). As for the specimen anodized in H_2SO_4, an oxide layer was generated thicker than that of the specimen anodized in NaOH. As a result, the amount of Ni dissolution decreased to about 40 % of that of as received specimen in the solution of pH 4.4. The amount of Ni dissolution from Ni-Ti orthodontic wires reduced when we properly performed anodic oxidation even if containing considerably amount of HF in the solution.","subitem_description_type":"Abstract"}]},"item_7_full_name_3":{"attribute_name":"著者別名","attribute_value_mlt":[{"nameIdentifiers":[{"nameIdentifier":"149916","nameIdentifierScheme":"WEKO"}],"names":[{"name":"Homma, Kikuo"}]}]},"item_7_publisher_7":{"attribute_name":"出版者","attribute_value_mlt":[{"subitem_publisher":"新潟歯学会"}]},"item_7_select_19":{"attribute_name":"著者版フラグ","attribute_value_mlt":[{"subitem_select_item":"publisher"}]},"item_7_source_id_11":{"attribute_name":"書誌レコードID","attribute_value_mlt":[{"subitem_source_identifier":"AN0018300X","subitem_source_identifier_type":"NCID"}]},"item_7_source_id_9":{"attribute_name":"ISSN","attribute_value_mlt":[{"subitem_source_identifier":"03850153","subitem_source_identifier_type":"ISSN"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"本間, 喜久男"}],"nameIdentifiers":[{"nameIdentifier":"149915","nameIdentifierScheme":"WEKO"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2019-08-19"}],"displaytype":"detail","filename":"NS_40(2)_131-141.pdf","filesize":[{"value":"2.9 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"NS_40(2)_131-141.pdf","url":"https://niigata-u.repo.nii.ac.jp/record/25428/files/NS_40(2)_131-141.pdf"},"version_id":"fb1456ee-fcd8-45d9-bdc1-92b4d4844934"}]},"item_keyword":{"attribute_name":"キーワード","attribute_value_mlt":[{"subitem_subject":"Ni-Ti 矯正用ワイヤ","subitem_subject_scheme":"Other"},{"subitem_subject":"陽極酸化","subitem_subject_scheme":"Other"},{"subitem_subject":"フッ化物","subitem_subject_scheme":"Other"},{"subitem_subject":"Ni 溶出","subitem_subject_scheme":"Other"},{"subitem_subject":"Ni-Ti orthodontic wire","subitem_subject_scheme":"Other"},{"subitem_subject":"Anodic oxidation","subitem_subject_scheme":"Other"},{"subitem_subject":"Fluoride","subitem_subject_scheme":"Other"},{"subitem_subject":"Ni dissolution","subitem_subject_scheme":"Other"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"jpn"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"departmental bulletin paper","resourceuri":"http://purl.org/coar/resource_type/c_6501"}]},"item_title":"陽極酸化を行ったNi-Ti 矯正用ワイヤのフッ化物を含む酸性溶液中での耐食性の評価","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"陽極酸化を行ったNi-Ti 矯正用ワイヤのフッ化物を含む酸性溶液中での耐食性の評価"},{"subitem_title":"陽極酸化を行ったNi-Ti 矯正用ワイヤのフッ化物を含む酸性溶液中での耐食性の評価","subitem_title_language":"en"}]},"item_type_id":"7","owner":"1","path":["456","1297"],"pubdate":{"attribute_name":"公開日","attribute_value":"2017-07-19"},"publish_date":"2017-07-19","publish_status":"0","recid":"25428","relation_version_is_last":true,"title":["陽極酸化を行ったNi-Ti 矯正用ワイヤのフッ化物を含む酸性溶液中での耐食性の評価"],"weko_creator_id":"1","weko_shared_id":null},"updated":"2022-12-15T03:55:22.147362+00:00"}