Microbiological analysis of absorbent paper points employed by undergraduate students from a dental school in south of Brazil

ABSTRACT

Aim: The aim of this study was identify contamination on absorbent paper points used by students of Dental Clinic III of the Faculty of Dentistry of Federal University of Rio Grande do Sul in the semester 2015/1, in order to warn students and professionals of the area on the importance to sterilize these materials. Material and Methods: In a clinical environment, 180 absorbent paper points we collected (80 of them from the first series and 80 from the second one), from 40 students. After the collection, each one was singly immersed in a microtube containing 1.5 ml of the BHI (Brain Heart Infusion) culture. Positive control was composed by one paper point contaminated by saliva, and negative control was composed by a closed microtube, only with BHI. The microtubes were incubated at 37ºC in bacteriological incubator during 14 days. The microtubes that presented turbidity were considered positive, and those which did not present turbidity were considered negative. Results: The results were analyzed by the Fisher Exact Test, which demonstrated that paper points from the second series presented higher agreement contamination between the paper points collected from each box, when compared to the analyzed boxes from the first series (p=0.03). All the samples observed presented growth of Bacillus spp in the microorganism identification. Conclusions: It is possible conclude that absorbing paper points, when exposed to clinical environment suffer contamination, and the autoclave sterilization is necessary before the use, regardless the commercial brand, in order to ensure the aseptic chain maintenance.