Screening of microbial contamination of radiographic films in order to avoid cross infection in maxillofacial surgery clinics

Abstract

Radiographic investigation in maxillofacial surgery is a vital procedure in minor as well as major surgical 
procedures in dentistry and in this Department, for example, both analog and digital radiography is used. 
Patient files are usually transferred from one clinic to another according to the patient appointments and 
most dentists and surgeons routinely handle these files before treating patients. Since radiographic films are 
not subjected to disinfection a variety of bacteria may be transferred from the oral cavity to these films and 
then to other patients via process of cross infection. Although most dental clinics are currently moving to 
digital technology even the use of this approach may lead to cross contamination, since the sensors and 
phosphor plates used in digital radiographs are also not generally autoclavable. The aim of the work 
described in this study was therefore to screen radiographic films used at the Maxillofacial Surgery clinics in 
the College of Dentistry, King Saud University for contamination with potentially pathogenic bacteria and 
fungi. A total of 447 radiographs films including periapical, occlusal and orthopantomograms (OPG) from 
patients treated at the clinics of Oral and Maxillofacial Surgery, College of Dentistry, King Saud University 
were collected in sterile plastic bags and screened for bacterial contamination. All films were swabbed using 
sterile swab sticks and bacteria were then identified using standard laboratory procedures. After 
identification of the contaminant bacteria, data were analyzed using SPSS software. The qualitative 
assessment of the tested samples showed that all tested radiographic films samples were contaminated with 
bacteria. Staphylococci (Staphylococcus aureus 33.8% and coagulase negative Staphylococcus epidermidis 
18.1%) were the most frequently isolated bacteria, although species of Streptococcus (3.6%) and Bacillus 
(3.6%) were also isolated; only 23.5% of the tested films were contaminated with fungi, mainly Aspergillus 
niger. This study demonstrates that radiographic films can be a source of cross infection in dental clinics and 
since these films are not subjected to any disinfection there is a need for the application of strict hygiene 
measures during their handling in order to avoid cross infection of microorganisms from these films.