title: Nitrous oxide control in the dental operatory: auxiliary exhaust and mask leakage, design, and scavenging flow rate as factors.
abstract: Two new local exhaust systems, intended primarily to control patient mouth emissions of N2O, were installed in a dental operatory, and resulting exposure concentrations to dental personnel were observed. The exposures were found to be typically unaffected by the presence and operation of these new controls. Laboratory testing on a head form, in conjunction with the operatory observations, established that mask leakage due to poor fit was the primary cause of N2O emissions. An improved mask fit and the addition of a slotted skirt around the outer mask shell individually resulted in greatly reduced leakage rates in the laboratory tests. Also, exhaust systems placed on the chin, on the chest, or in the mouth proved effective in capturing mouth emissions simulated by a breathing machine and head form.
authors.affiliation: U.S. Department of Health and Human Services, Center for Disease Control and Prevention, Cincinnati, Ohio 45226, USA.
authors.forename: K G
authors.initials: KG
authors.lastname: Crouch
authors.forename: O E
authors.initials: OE
authors.lastname: Johnston
mesh_terms: D003748:Dental Equipment; D003813:Dentistry; D004867:Equipment Design; D006801:Humans; D009609:Nitrous Oxide; D016273:Occupational Exposure; D012134:Respiratory Protective Devices; D014691:Ventilation
chemical_list: D009609:Nitrous Oxide