The photodynamic therapy on Streptococcus mutans biofilms using erythrosine and dental halogen curing unit

Abstract

The purpose of our study was to evaluate the effect of photodynamic therapy (PDT), using erythrosine as a photosensitizing agent and a dental halogen curing unit as a light source, on Streptococcus mutans in a biofilm phase. The S. mutans biofilms were formed in a 24-well cell culture cluster. Test groups consisted of biofilms divided into four groups: group 1: no photosensitizer or light irradiation treatment (control group); group 2: photosensitizer treatment alone; group 3: light irradiation alone; group 4: photosensitizer treatment and light irradiation. After treatments, the numbers of colony-forming unit (CFU) were counted and samples were examined by confocal laser scanning fluorescence microscopy (CLSM). Only group 4 (combined treatment) resulted in significant increases in cell death, with rates of 75% and 55% after 8 h of incubation, and 74% and 42% at 12 h, for biofilms formed in brain–heart infusion (BHI) broth supplemented with 0% or 0.1% sucrose, respectively. Therefore, PDT of S. mutans biofilms using a combination of erythrosine and a dental halogen curing unit, both widely used in dental clinics, resulted in a significant increase in cell death. The PDT effects are decreased in biofilms that form in the presence of sucrose.

Zinc enhances the phototoxic effect of blue light against malodour-producing bacteria in an experimental oral biofilm

“…This hypothesis is further supported by the observation that obligate anaerobic oral bacteria (pigmented and non-pigmented) are more susceptible to blue light exposure treatment than facultative ones (Feuerstein et al, 2004;Sterer & Feuerstein, 2005). Various studies have reported that using the colourant erythrosine B as a photosensitizer enhances the antimicrobial properties of blue light from light-emitting diode (LED) or halogen light sources (De Lucca et al, 2012;Lee et al, 2012). In our study, the addition of erythrosine B did cause some reduction in malodour; however, this reduction was not statistically significant.…”

Photodynamic antimicrobial chemotherapy and ultraconservative caries removal linked for management of deep caries lesions

“…The relative high susceptibility of cariogenic bacteria, such as S. mutans and L. acidophilus, to PACT using a diverse collection of photosensitizers and light sources is adequately documented [23][24][25]. Others have examined the effectiveness of PACT with TBO associated to a LED as light source and innumerous investigations have shown great bacterial reduction (log reduction up to 5) or even the fully elimination of, when these bacteria are suspended in planktonic cultures [8,26] or organized in in vitro biofilms [11,26].…”

Photodynamic and Tissue Tolerable Plasma Therapies as Alternatives to Antimicrobials to Control Pathogenic Biofilms

“…However, possibly because of the limitation of light penetration and drug diffusion, microorganisms were less affected in the biofilm phase than the planktonic counterparts (references). Moreover, Lee et al [43] were able to achieve significant cell death using erythrosine as a photosensitizing agent and a dental halogen light on S. mutans biofilm. Nevertheless, for dental use, several aspects, including energy, light irradiation times, and distance to the targeted area, must be carefully analyzed, aiming at tissue-tolerable temperature in the dentin, pulp, and other oral tissues.…”