Effect of a mechanical ventilation system (exhaust fan) integrated with chlorination on reducing bacterial colonies in dental treatment rooms
Abstract
Background: Microbial air contamination (bioaerosols) in dental treatment rooms poses a significant risk for the transmission of Healthcare-Associated Infections, particularly during aerosol-generating procedures. Limited studies have evaluated integrated ventilation and disinfection systems to control airborne bacteria.
Objective: This study aimed to evaluate the effectiveness of a mechanical ventilation system (exhaust fan) integrated with calcium hypochlorite disinfection in reducing airborne bacterial colonies.
Methods: A quasi-experimental study with a pretest–posttest design was conducted under four conditions: P1 (before ventilation), P2 (after ventilation), P3 (outlet without disinfection), and P4 (outlet with calcium hypochlorite). Air sampling was performed using the settle plate method with five Nutrient Agar plates exposed for 15 minutes at a height of one meter. The exhaust fan was operated for one hour prior to sampling. Each condition was repeated 15 times. Bacterial colonies were quantified and converted into CFU/m³ using the Omeliansky formula.
Results: The baseline bacterial concentration was 211.04 CFU/m³. Ventilation significantly reduced bacterial colonies to 100.63 CFU/m³ (p = 0.015). No significant difference was observed between indoor and outlet air (p = 0.297). The addition of calcium hypochlorite significantly reduced bacterial colonies to 16.07 CFU/m³ (p < 0.001).
Conclusion: Mechanical ventilation reduces airborne bacterial load, and integration with calcium hypochlorite disinfection effectively minimizes microbial contamination before air is released into the environment.
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