Analyzing the Bacterial Load on Dental Waiting Room Chairs Using an ATP System

Danno, Andrew, John Shaba, Deveen Gabrail, Mohamad Bazzi, and Michelle Wheater

Introduction: The chair handles in a dental clinic waiting room are continually touched as patients pass in and out. Bacteria can survive on the surfaces of inanimate objects, for this reason the objective of the current study was to determine levels of bacteria on waiting room chair handles. Methods: Levels of bacteria were measured using the Ruhof ATP Complete Contamination Monitoring System (Ruhof Corporation, Mineola, NY). This system detects microbial contamination by detecting ATP levels and providing a numerical readout on a hand-held measuring device. Test swabs in a container filled with a liquid-stable reagent were swabbed on the handle of the designated chairs. The first half of the right handle was swabbed in a clockwise direction going up to the half-way mark, and then swabbed in a counterclockwise motion coming back from the half-way mark. Once the handle was swabbed, the swab was placed into the device to measure ATP levels. The same 20 chairs were measured throughout the entire experiment, with chairs analyzed for a total of two weeks with two sets of five consecutive days, Monday through Friday. Results: According to the Ruhof detection system, a numerical reading of less than 45 for non-critical surfaces such as those in waiting rooms is considered “pass,” or not significantly contaminated. Readings greater than 46 are recorded as a “fail” indicating a contaminated surface. Of the 200 tests completed in this study, 21 (10.5%) of the readings were less than 45. The mean reading for week one was 140, and for week two the mean reading was 104, indicating a “fail” and suggesting consistent contaminated surfaces on waiting room chairs throughout both weeks of the study. During the first week, Friday had two chairs with readings of 418 and 740. Because of this, for the first week the readings for Friday were significantly greater than for the other four days tested (p < 0.05). There were no obvious differences between days of the week for week 2. Conclusion: Based on the Ruhof system of detecting bacterial ATP, the results of this study suggest that there is a significant amount of contamination on waiting room chairs at Detroit Mercy Dental.