Control of anesthetic gases in dental operatories.
McGlothlin JD; Jensen PA; Fischbach TJ; Hughes RT; Jones JH
Scand J Work Environ Health 1992 Jun; 18(Suppl 2):103-105
Field studies of dental operatories using scavenging systems were conducted to gather information regarding the control of nitrous- oxide (10024972) (N2O). Real time N2O sampling was conducted during each dental operation, and work activities were videotaped. The sampling port of the analyzer was located near the breathing zone of the dentists and their assistants. The N2O concentrations recorded in a pediatric dental clinic exceeded the 25 parts per million (ppm) recommended exposure limit (REL) in 100% of the cases for both the dentists and their assistants. The mean N2O concentration was 438ppm for dentists and 141ppm for dental assistants. The dentists and oral surgeons worked 8 to 15 inches from the patient's breathing zone while the assistants worked 15 to 30 inches away. The mask did not fit the patient's face properly and there was N2O leakage between the mask and the face seal. The flow rate of the scavenging system was 7 to 12 liters/minute, while the recommended rate is 45 liters/minute. In an oral surgical clinic, the N2O levels exceeded the REL for the oral surgeons in 50% of the operations and for the assistants in 29%. The authors conclude that control of N2O exposures to 25ppm during administration can be achieved with the use of a proper scavenging system exhaust rate, the use of a mask with good patient fit, good work practices, and proper maintenance of the scavenging and delivery systems.
NIOSH-Author; Air-quality-monitoring; Dental-laboratories; Dentistry; Nitrogen-oxides; Occupational-exposure; Control-technology
Dr. JD McGlothlin, National Institute for Occupational Safety and Health, Division of Physical Sciences and Engineering, Cincinnati, OH 45226, USA
Scandinavian Journal of Work, Environment & Health