Abstract
Although nitrous oxide (N2O) has been widely used since 1844, in recent years it has been implicated in a number of serious health hazards such as reproductive, nerve, liver, and kidney disorders. The National Institute of Safety and Health (NIOSH) recommends a limit of 25 ppm for chronic exposure to N2O in the dental office. Our study monitored ambient N2O levels in the dental office. N2O levels were compared for procedures performed in open clinics and private operatories as well as with and without a gas-scavenging system. Measurements were taken in the Dental Breathing Zone (DBZ) and Dental Chair Foot (DCF) at regular intervals. A four- to eightfold increase in average N2O levels was noted in the DBZ for unscavenged versus scavenged procedures. A three- to fourfold increase for unscavenged versus scavenged procedures was similarly noted in the DCF. N2O were significantly higher in private operatories than in open clinics, due to limited room volumes and in the DBZ over the DCF, due to mask leakage and increased oral exhalation. Scavenged N2O levels for both operatory types did not meet NIOSH guidelines. In contrast to previous studies using any form of gas removal, our study shows a significant decrease in N2O level achieved with an adequate scavenger system. With only four states regulating the use of N2O, and with concern over its deleterious effects growing, additional states and the federal government are expected to enact legislation regulating the use of N2O in the near future.
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