Effect of Cleaning and Disinfection on Naturally Contaminated Clinical Contact Surfaces

Introduction. Data regarding methicillin-resistant Staphylococcus aureus, Legionella pneumophila, Hepatitis B virus suggest that the environment plays an important role in infection transmission in dental healthcare settings. The Centres for Disease Control and Prevention suggest covering clinical contact surfaces with disposal barriers or disinfecting them between patients. Both methods have drawbacks; preliminary data suggest that cleaning could be an alternative. Aim. To investigate microbial contamination on dental chairs after dental therapy with turbine and decontamination power of disinfection and cleaning. Material and methods. We assessed microbial contamination of a dental chair, used by paediatric patients receiving conservative/endodontic therapy and located in an annex isolated from the rest of the dental office. Contact plates containing Nutrient Agar were used to assess microbial load, immediately before and after treatment, and following one of two decontamination protocols. Protocol-1 comprised cleaning (sodium lauryl sulphate-based soap) followed by disinfection (hypochlorite solution); and protocol-2 was soap-based cleaning only. Contamination levels were classified as no growth; scanty (<2.5 CFU/ cm2); light (2.5-12 CFU/cm2); moderate (12-40 CFU/cm2); or heavy growth (40-100 CFU/cm2). Results. Contamination ranged between moderate and heavy growth for 93.3% samples after dental therapy before decontamination. Scanty growth was obtained from 93.3% samples and 96.7% samples after protocol 1 and protocol-2, respectively. Initial level of contamination had no significant effect on the final level and the decontamination power of the two protocols was not significantly different either. Conclusion. Dental therapy produced high levels of microbial contamination which justified the use of adequate disinfection and/or cleaning. Cleaning alone was sufficient to decontaminate the surface of the dental chair, while disinfection offered no additional effect.