Control of occupational exposure to nitrous oxide in the dental operatory

Methods were developed for controlling the dental team's occupational exposure to nitrous oxide. The most applicable and effective use of these methods included the use of properly maintained gas delivery equipment, a double-walled scavenging nosepiece and vented suction machine, and minimizing speech by the patients. These methods were evaluated by measuring concentrations of nitrous oxide present in the air inspired by dental personnel. Before their use, the dentist inhaled 900 ppm nitrous oxide; their application reduced his inhaled concentration to 31 ppm, representing a 97% reduction. These methods were well accepted during 157 procedures completed by a group of eight dentists engaged in private practice (four general practitioners, two pedodontists, and two oral surgeons).