Airborne microbial contamination of dental units

ABSTRACT

Occupational risk of dental personnel to microbial airborne contamination has been demonstrated through the increased prevalence of respiratory infections. The American Dental Association has suggested stringent protection for infectious agents present in dental aerosols. Materials and Occupational exposure of dentists to airborne microbial and mycological contamination in various locations of a dental school was monitored by sampling of air in close vicinity of their breathing zone. This sampler drew air at a flow rate of 10 liters/minute and for a 2-hour period and blew it at a high speed through a narrow slit over a solid nutrient agar plate. Immediately after sampling, the plates were placed in an incubator and incubated aerobically for 2 days at 37C. The total bacterial counts in the air of dental surgery rooms and in non-surgery rooms without direct involvements with dental operations were in the range of 120-280 cfu/m3 and 49-128 cfu/m3 respectively. Pathogenic Streptococcus haemolyticus and opportunistic Staphylococcus species were found in some locations of dental surgery rooms. There are no standards for acceptable levels of indoor air contamination with pathogenic microorganisms and since pathogenic Streptococcus haemolyticus and opportunistic Staphylococcus species were found in some areas of the dental school, the need for management of possible risk of infective hazards is recognized