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Microbial contamination of dental unit waterlines and effect on quality of indoor air

Environmental Monitoring and Assessment volume 186, pages 3431–3444 (2014)Cite this article

Abstract

The microbiological quality in dental unit waterlines (DUWLs) is considered to be important because patients and dental staff with suppressed immune systems are regularly exposed to water and aerosols generated from dental units (DUs). Opportunistic pathogens like Pseudomonas, Legionella, Candida, and Aspergillus can be present in DUWLs, while during consultations, bioaerosols can be dispersed in the air, thus resulting in effects on microbiological quality of indoor air. This present study represents microbiological air and water quality in dental offices (DOs) and also concerns the relationship between the quality of DO air and dental unit water. This study aimed to assess both the microbial quality of dental unit water and the indoor air in 20 DOs and to survey the effect on the quality of the indoor air with the existing microorganisms in dental unit water. Fourteen out of 20 (70 %) DUWLs were found to be contaminated with a high number of aerobic mesophilic heterotrophic bacteria. In terms of bacterial air contamination levels, in 90 % of DOs, a medium level (<500 colony-forming units (CFU)/m3) of contamination was determined, while in terms of microfungal air contamination, in all DOs, a low level (<100 CFU/m3) of contamination was determined. Potential infection or allergen agents, such as Pseudomonas, Micrococcus, Staphylococcus, Alternaria, Cladosporium, Penicillium, Aspergillus, and Paecilomyces were isolated from water and air samples. This study’s determination of contamination sources and evaluation of microbial load in DOs could contribute to the development of quality control methods in the future.

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Acknowledgments

We gratefully thank to Prof. Dr. Ahmet ASAN and Dr. Burhan SEN for the assistance about sharing the laboratory facilities. This work was supported by the “Research Fund of Istanbul University” (project number 1847, UDP–14595).

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  1. Department of Biology, Faculty of Science, Istanbul University, Vezneciler, 34134, Istanbul, Turkey

    Duygu Göksay Kadaifciler & Aysin Cotuk

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  1. Duygu Göksay Kadaifciler
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Correspondence to Duygu Göksay Kadaifciler.

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Kadaifciler, D.G., Cotuk, A. Microbial contamination of dental unit waterlines and effect on quality of indoor air. Environ Monit Assess 186, 3431–3444 (2014). https://doi.org/10.1007/s10661-014-3628-6

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Keywords

  • Aerobic mesophilic heterotrophic bacteria
  • Bioaerosol(s)
  • Dental unit waterlines
  • Indoor air quality
  • Microbial contamination
  • Microfungi