Indian Journal of Public Health Research & Development

The irrigants used commonly do not always eradicate the entire microbial flora in infected root canals. Thus in quest other strategies, such as photodynamic therapy (PDT) have been developed. The word photodynamic means the applications of the dynamics of photons of light on the biological molecules. German physician Friedreich Mayer performed the first study, which was first called as photo-radiation therapy with porphyrins (1913) in humans. Photoactivated disinfection is based primarly on the interaction of a photosensitive antibacterial agent and a light source which uses a nontoxic dye named photosensitizer (PS) and lowintensity visible light. In the presence of oxygen, these combine to produce some cytotoxic species. The PS molecules attach to the bacteria membrane. Irradiation with a specific wavelength of the light may result in the production of singlet oxygen, resulting in rupture of the microbial cell wall. There are several applications for PDT in dentistry.. Photodynamic therapy has also been used to disinfect caries dentin before the restoration, disinfecting oral tissues before or during surgical procedures, treating denture stomatitis, and treating oral candidiasis in immunocompromised patients. Photodynamic therapy can also be used in combination with mechanical instrumentation and chemical antimicrobial agents, such as sodium hypochlorite.