Effective use of an extraoral vacuum in preventing the dispersal of particulate matter from metal dental materials.

"CONFLICT OF INTEREST STATEMENT The local exhaust ventilation system used in this study was not provided by Tokyo Giken, and all other instruments and materials were purchased and placed at the expense of our hospital. Therefore, the authors have no conflicts of interest to declare. DISCLOSURES Ethical approval: The study protocol was approved by the Ethics Committee of Tokushima University Hospital (Approval No. 3515), and the study was conducted as per the ethical guidelines of this hospital and the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Informed consent: Consent was obtained from all researchers who participated in this study. Registry and the registration no. of the study/trial: N/A. Animal study: N/A."