Combination of 10% EDTA, Photosan, and a blue light hand-held photopolymerizer to inactivate leading oral bacteria in dentistryin vitro

AIMS: The goal of this study was to investigate the phototoxicity of Photosan in combination with EDTA and a hand-held photopolymerizer used in dentistry for light-curing resins against leading key pathogens in caries, endodontic treatment failures, and periodontitis respectively. METHODS AND RESULTS: Cellular uptake of Photosan was detected by fluorescence spectroscopy for Streptococcus mutans and Enterococcus faecalis but not for Aggregatibacter actinomycetemcomitans. Addition of 10% EDTA enabled the uptake of Photosan by A. actinomycetemcomitans. Killing of S. mutans and E. faecalis mediated by Photosan and blue light was concentration and light dose dependent, achieving a >or=99.9% (>or=3 log(10) reduction) efficacy of bacteria killing. In the presence of 10% EDTA, Photosan induced a reduction of >or=4 log(10) in the viability of A. actinomycetemcomitans at a concentration of 50 microg ml(-1), upon activation at a dose of 9.65 J cm(-2) for 60 s. EDTA alone, light alone, and Photosan alone were not able to kill bacteria. CONCLUSIONS: Ten per cent EDTA and Photosan cause a potent phototoxicity against oral bacteria upon illumination with a photopolymerizer. SIGNIFICANCE AND IMPACT OF THE STUDY: Increasing antibiotic resistance and insufficient drug concentrations within the sulcus fluid are responsible for lacking antimicrobial efficacy. This study provides useful information that combination of Photosan, EDTA, and a photopolymerizer may be a potentially powerful tool for the efficient destroying of key oral bacteria.