The efficacy of disinfectants in the decontamination of dental unit water lines: an in vitro laboratory study.

Mrudula Patel,Peter C Owen,Jainisha Desai

doi:10.1038/bdjopen.2016.3

Abstract

Objectives/Aims:This in vitro laboratory study compared the efficacy of water, sodium percarbonate (SPC) and chlorine dioxide (ClO2) solutions in the disinfection of dental unit water lines (DUWLs).Materials and Methods:New DUWL tubes were cut, split open, and mono-culture and mixed-culture biofilms of Staphylococcus aureus, Enterococcus faecalis and Streptococcus mutans were grown. Harvested biofilms from the sectioned DUWL tubes were exposed to sterile distilled water, SPC or 5 and 10 p.p.m. ClO2 in both a stationary phase and through a constant flow. Bacterial counts were compared using the Kruskal–Wallis nonparametric rank test.Results:In the mono-culture biofilms, SPC, 5 and 10 p.p.m. ClO2 significantly reduced all the test organisms (P<0.01). However, no significant difference was found between SPC and ClO2. In the mixed-culture biofilms exposed to disinfectant without flow, ClO2 significantly reduced the biofilm (P=0.02) compared with water and SPC. Similarly, in the constant flow study, ClO2 proved to be superior to water.Conclusion:At low concentrations, ClO2 with and without flow significantly reduced the mixed-culture biofilm grown in vitro on the sections of the DUWL tubes. Therefore, it has the potential to be used in the patient treatment water, as it is potable at these concentrations, and to decontaminate and limit the biofilm formation in the water lines.

Highlights

The dental chair unit contains water lines that supply water from a reservoir or municipal supply to the handpieces, the triplex air/water syringe and spittoon
The adherence ability of S. mutans was found to be weaker than S. aureus and E. faecalis
As the results in our study have shown, Environmental Protection Agency (EPA) approved chlorine dioxide (ClO2) is an excellent biocide and its use in dental unit water lines (DUWLs) has been recommended.[1,6]

Summary

INTRODUCTION

The dental chair unit contains water lines that supply water from a reservoir or municipal supply to the handpieces, the triplex air/water syringe and spittoon These lines vary in thickness and material construction, and become contaminated with environmental microorganisms, pathogens and opportunistic pathogens. Among the many physical methods that can improve the microbiological quality of DUWL output water, the use of disinfectant is the most efficacious means of ensuring decontamination. Chemicals such as sodium percarbonate (SPC), hydrogen peroxide and sodium perborate have been tested and they have shown variable efficacy[4] mainly owing to the different test concentrations and the type of interventions. This study compared the efficacy of a commonly used product, SPC and newly available product, chlorine dioxide (ClO2), in the disinfection of DUWLs and their possible use during patient treatment

MATERIALS AND METHODS

RESULTS

Experiments

CONCLUSION