Photodynamic therapy for dental plaque treatment

The anatomical complexity of tooth roots provides place for bacterial deposits, making eradication of periodonto pathogens difficult. The conventional methods for the removal of dental plaque like mechanical treatment and antimicrobial therapy have their own limitations. To overcome the limitations, a novel non-invasive photochemical approach called Photodynamic Therapy (PDT) was applied which is based on the principle that a visible range of light activates a photosensitizer (PS), leading to the formation of reactive oxygen species which induce phototoxicity to the bacterial cell. In this project, a light source was designed using red Light Emitting Diode (LED) to illuminate the biofilm formed by Streptococcus viridians group. The biofilm was formed in 96 well microtiter plates and was sensitized with Toluidine Blue O (TBO) of two concentrations (500mg/l, 100mg/l). The viability of cells when evaluated using MTT ((3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay was found to be decreased significantly. It was also found that high concentration of TBO (HTBO-500mg/l) was more effective assuming that the biofilms were exposed with equal intensity of light.