2021 Fiscal Year Final Research Report

Health effects in dental technicians exposed dental indium alloy

Research Project

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Project/Area Number	19K10663
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 58030:Hygiene and public health-related: excluding laboratory approach
Research Institution	Kyushu University
Principal Investigator	Hirata Miyuki 九州大学, 医学研究院, 助教 (30156674)
Co-Investigator(Kenkyū-buntansha)	中野真規子慶應義塾大学, 医学部(信濃町), 講師 (70384906) 宮内博幸産業医科大学, 産業保健学部, 教授 (90784025) 山下喜久九州大学, 歯学研究院, 教授 (20192403) 岡元昌樹独立行政法人国立病院機構九州医療センター(臨床研究センター), その他部局等, 呼吸器内科医長 (50352133) 田中昭代九州大学, 医学研究院, 講師 (10136484)
Project Period (FY)	2019-04-01 – 2022-03-31
Keywords	インジウム / 歯科技工士 / 肺障害 / 健康影響 / 歯科合金
Outline of Final Research Achievements	As dental technicians are exposed to a variety of chemicals such as dental alloys containing indium, and may give rise to work-related respiratory symptoms, the aim of this study was to estimate indium exposure of dental technicians. A cross-sectional study was performed among 67 dental technicians working at 19 dental laboratories. Subjective symptoms were assessed, including serum indium level (InS), serum KL-6 and self-report pulmonary questionnaire. The prevalence of increased InS levels was 17.9% (12 workers), and the highest level of InS was 0.6ng/mL. All the 12 workers were treated with dental alloys. The prevalence of abnormal KL-6 was 3.0% (2 workers), and that of pulmonary symptoms was cough/sputum; 44.0%, wheezing/breathlessness; 30.0%. No marked differences of pulmonary symptoms were observed between two groups as to whether or not to treated dental alloys. As InS of all subjects was below the biologically acceptable level (3 ng/mL), indium exposure was considered low.
Free Research Field	産業衛生学
Academic Significance and Societal Importance of the Research Achievements	現在、特定化学物質障害予防規則（特化測）の「インジウム化合物」には歯科合金を含む金属インジウムは含まれないが、その理由には金属インジウムに関する有害情報が不足しているためであった。今回、インジウム含有歯科合金の研磨粉塵や鋳造蒸気を吸入する歯科技工士において低レベルのインジウム曝露が認められ、肺CT検査では検査対象者14名中3名にすりガラス状異常影が認められた。歯科技工士の健康診断を定期的に実施し、血清インジウム濃度測定および胸部X線検査、必要時には胸部CT検査を行って、健康管理を行うことが重要と考えられる。