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Reduction of enterococcus faecalis biofilm by blue light and sodium hypochlorite

Indiana University-Purdue University Indianapolis (IUPUI) / Introduction: Microbial biofilms have been shown to be a cause of persistent
endodontic infections. It is more resistant than planktonic bacteria to host immune
defenses and antimicrobials. Studies indicate that photodynamic light therapy (PDT),
which involves using light at specific wavelengths, has a potent antibacterial effect on
bacterial biofilm. PDT is an antimicrobial strategy that involves the use of a nontoxic
photosensitizer (PS) along with a light source. The excited PS reacts with molecular
oxygen to produce highly reactive oxygen species, which induce injury or death to
microorganisms. PSs have a high degree of selectivity for inhibiting microorganisms
without negatively affecting host mammalian cells. PDT has been suggested as an
adjuvant to conventional endodontic treatment. Studies at IUSD have shown that blue
light at 380 nm to 440 nm has the ability to inactivate Streptococcus mutans biofilm
without any exogenous PS.

Objective: The objective of this study was to determine the effectiveness of blue
light at 380 nm to 440 nm to reduce adherence of Enterococcus faecalis biofilm after
NaOCl irrigation at various concentrations.

Materials and Methods: E. faecalis biofilm was established for 72 hours in 96-
well flat-bottom microtiter plates using Tryptic Soy Broth supplemented with 1.0-percent
sucrose (TSBS). Biofilm was irradiated with blue light for 5 minutes before exposure to
various concentrations of NaOCl for 30 seconds. A crystal violet biofilm assay was used
to determine relative density of the biofilm. Data were analyzed with two-way ANOVA
and Sidak-adjusted multiple comparisons using a 5.0-percent significance level.

Null Hypothesis: Blue light and NaOCl will not have an effect against E. faecalis
biofilm adherence.

Results: Overall, there was a significant effect (p < 0.05) for NaOCl and a
significant effect for blue light. The effects of the combination of NaOCl and blue light
were also significant.

Conclusion: We reject the null hypothesis and accept the alternative hypothesis
that blue light when used in conjunction with NaOCl will reduce adherence of E. faecalis
biofilm.

Identiferoai:union.ndltd.org:IUPUI/oai:scholarworks.iupui.edu:1805/13162
Date January 2017
CreatorsKwan, Daryl A.
ContributorsGregory, Richard L., Spolnik, Kenneth J., Bringas, Josef S., Zunt, Susan L., Ando, Masatoshi, Ehrlich, Ygal
Source SetsIndiana University-Purdue University Indianapolis
LanguageEnglish
Detected LanguageEnglish
TypeThesis

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