Microbial Air Quality and Standard Precaution Practice in a Hospital Dental Clinic
Pipat Luksamijarulkul MSc*, Navapan Panya MSc**, Dusit Sujirarat MSc***, Sroisiri Thaweboon PhD****
Affiliation : * Department of Microbiology, Faculty of Public Health, Mahidol University, Bangkok, Thailand ** Lamplaimat Hospital, Buriram Province, Thailand *** Department of Epidemiology, Faculty of Public Health, Mahidol University, Bangkok, Thailand **** Department of Microbiology, Faculty of Dentistry, Mahidol University, Bangkok, Thailand
Objective : 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.
Material and Method: 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 α = 0.05.
Results : The results revealed that standard precaution practices towards wearing personal protective equip-
ments 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.
Conclusion : 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.
Keywords : Dental clinic, Standard precaution practice, Microbial counts, Indoor air quality
