Objectives: Swabbing is a commonly used method to examine levels of bacterial contamination in dental practices. Here we developed a novel technique of sampling bacteria, termed stamping technique, to monitor bacterial contamination on surface-protecting dental plastic barriers. Furthermore, following dental procedures, we compared the efficacy of the stamping technique to the conventional swabbing method.
Methods: After dental procedures were provided to 5 patients at Tufts University School of Dental Medicine, the plastic barriers were removed from the lamp handles, light switch, X-ray cone, X-ray button, tray handle, suction/air/water tubes, composite resin curing light, and the keyboard and mouse at the chair-side computer. Each plastic barrier was cut in half. One half of the barrier was swabbed with a sterile alginate swab that was dissolved in 1ml Ringer's solution, and 200ml samples were seeded on Trypticase Soy Agar plates. The other half of the barrier was stamped on these plates. Plates were incubated aerobically at 370C for 24-48hr, and the number of bacterial colonies was counted.
Results: From 30 barriers that were collected after dental procedures, 28 barriers (93.3%) showed a higher bacterial colony count from the stamping technique when compared to the swabbing method. Only 2 barriers (6.7%) showed a higher colony count after swabbing. Moreover, while over 1500 bacterial colonies were grown using the stamping technique less than 300 colonies were grown from the swabbing method, indicating a 5-fold increase in bacterial detection sensitivity by the stamping technique.
Conclusions: This study demonstrates that our novel stamping technique is more sensitive in determining the level of bacterial contamination in the dental clinic, when compared to the conventional swabbing method. This is due, at least in part, to the direct rather than indirect bacterial transfer from surface-protecting barriers to the agar by the stamping technique and the swabbing method, respectively.
Keywords: Bacterial, Effectiveness, Evaluation, Methodology and Microbiology