Microbial air quality and standard precaution practice in a hospital dental clinic

A cross-sectional study was carried out to assess standard precaution practices among dental personnel and to investigate microbial counts in indoor air samples collected from a hospital dental clinic before and during dental works.

Thirty dental personnel who voluntarily participated were interviewed using a questionnaire towards demographic information and standard precaution practices between May and August 2007. Additionally, 138 indoor air samples (72 from dental treatment units, 48 from dental supporting units and offices and 18 from patient waiting area) were collected before and during dental works for 6 days (Monday to Saturday) to investigate bacterial and fungal counts. Data were analyzed by using descriptive statistics. Paired t-test was used for analyzing the difference of mean + standard deviation between microbial counts before and during dental procedures. The statistical significance was expressed in term of p-value and the critical level was set at alpha = 0.05.

The results revealed that standard precaution practices towards wearing personal protective equipments regularly during dental procedures ranged from 50% to 100%, whereas, cleaning and disinfecting dental unit after each patient treatment and cleaning dental unit water lines with antiseptics every week were done regularly only 36.7%. The mean score of standard precaution was 8.4 +/- 2.5 (moderate level, total score of 13). The means of bacterial and fungal counts in air samples collected from dental treatment units significantly increased during dental procedures when compared with those collected before dental works (p < 0.001), whereas, those were not significantly different in the dental supporting units and offices, p > 0.05.

This study demonstrated the moderate level of standard precaution practice score among studied dental personnel and significantly higher microbial counts (bacterial and fungal counts) in air samples collected from dental treatment units during dental procedures were demonstrated. To reduce the occupational risk among this group, standard precaution practices should be strengthened.