Effect of visible light on malodour production by mixed oral microflora

Abstract

Oral malodour is considered to be caused by the proteolytic activity of anaerobic Gram-negative oral bacteria. In a previous study, it was shown that these bacteria were susceptible to blue light (wavelengths of 400-500 nm). In this study, the effect of blue light on malodour production by mixed oral microflora was tested in a salivary incubation assay. Whole saliva samples were exposed to a xenon light source for 30, 60, 120 and 240 s, equivalent to fluences of 34, 68, 137 and 274 J cm À2 , respectively. Malodour was scored by two judges. The levels of volatile sulfide compounds (VSC) were measured using a sulfide monitor (Halimeter), the microbial population was assessed using viable counts and microscopy, salivary protein degradation was followed by SDS-PAGE densitometry and VSC-producing bacteria were demonstrated using a differential agar. The results showed that the exposure of mixed salivary microflora to blue light caused a reduction in malodour production concomitant with a selective inhibitory effect on the population of Gram-negative oral bacteria. These results suggest that light exposure might have clinical applications for the treatment of oral malodour.

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

“…photodynamic treatment) has been reported in the literature (Wilson, 1994;Henry et al, 1995Henry et al, , 1996Konig et al, 2000;Soukos et al, 2005), and it has been suggested that this effect is mediated through the production of ROS (Gourmelon et al, 1994). 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).…”

“…A previous study has demonstrated that exposing mixed planktonic bacteria from saliva to non-coherent blue light results in reduced malodour production in a salivary incubation assay (Sterer & Feuerstein, 2005). In the present study, an experimental biofilm system was utilized.…”

“…Various studies have demonstrated the antibacterial effect of visible light applied with or without exogenous photosensitizers (Wilson, 1994;Henry et al, 1995Henry et al, , 1996Konig et al, 2000;Soukos et al, 2005;Sterer & Feuerstein, 2005). It was further suggested that light-induced production of reactive oxygen species (ROS) is the mechanism underlying this phototoxic effect (Gourmelon et al, 1994).…”

Effect of Green Tea on Volatile Sulfur Compounds in Mouth Air

“…Consequently, the saliva-putrefaction system has shown that green tea, mints and toothpaste exhibited encouraging values that dispose one to accept these products as efficient VSC inhibitors. A saliva-putrefaction system has been employed in other studies to determine the efficacy of products in reducing oral malodor (23)(24)(25). However, when a treatment is carried out on saliva itself, as in this study, in vitro results do not always conform to in vivo results.…”

Micro gas analyzers for environmental and medical applications

“…Halimeters ® are now mostly used in dental clinics [122][123][124][125]. However, a Halimeter does not identify the composition of sulfur compounds.…”