Photodynamic therapy in oral diseases

Photodynamic therapy (PDT), also known as photoradiation therapy, phototherapy, or photochemo therapy, involves the use of a photoactive dye (photosensitizer) that is activated by exposure to light of a specific wavelength in the presence of oxygen. The transfer of energy from the activated photosensitizer to available oxygen results in the formation of toxic oxygen species, such as singlet oxygen and free radicals. These very reactive chemical species can damage proteins, lipids, nucleic acids, and other cellular components.Applications of PDT in dentistry are growing rapidly in treatment of oral premalignant and malignant conditions and oral microbiological diseases (bacterial and fungal infection therapies,) and the photodynamic diagnosis (PDD) of the malignant transformation of oral lesions. The absence of genotoxic and mutagenic effects of PDT is an important factor for long-term safety during treatment. PDT also represents a novel therapeutic approach in the management of oral biofilms. Studies are now leading toward selective photosensitizers, since killing the entire flora leaves patients open to opportunistic infections. This review emphasis on the various fundamental aspects of photodynamic therapy and the research done till date in treating various oral lesions using this new therapeutic approach