Evaluation of the Bacterial Contamination of Dental Units in Restorative and Peridontics Departments of Dental School of Shahid Beheshti

Surface bacterial contamination has been shown to be a potential source of cross infection. Our objective therefore was to determine the level and type of bacterial contamination present on dental units in two departments of dental school before and after treatment in 2011 and 2012. The study was carried out at Shahid Beheshti University of Medical Sciences (dental school). A random survey of 30 dental units from restorative and periodontics departments were included in this study. The surface of three sites of the units (seat, light on/off switch and tray handle) was sampled using moist sterile swabs. The colony forming units were counted and isolated bacteria were characterized by morphological and biochemical analyses. Comparisons of data sets were performed using the Wilcoxon, Mann-Whitney test and the Chi-square tests; P<0.05 was considered as statistically significant. Of the samples after work, 57 from 90 were positive for bacterial isolates. Staphylococcus oreus was more prevalent on the surfaces. Also, bacterial contamination of the seat was greater than the other parts (P=0.025). The isolates were significantly (P=0.036) more prevalent on units from restorative department than on those from periodontics department. Microbial contamination of dental units is considerably increased after treatment of each patient. So, surfaces disinfection is essential between patients treatment.