Photodynamic Therapy: A New Modality Treatment in Pre-Cancer and Cancer Patients

Introduction: Photodynamic therapy (PDT) is a new modality of therapy being used for the diagnosis and treatment in pre-cancer and cancer patients and various skin diseases. Photodynamic therapy is a powerful lightinitiated photochemical reaction, involving the use of a photoactive dye (photosensitizer) activated by light of a specific wavelength in the presence of oxygen. This leads to the formation of oxygen free radicals which are toxic, which can damage proteins, lipids, nucleic acids and other components. Application of photodynamic therapy in dentistry is growing rapidly for the use of oral pre-cancers and cancer lesions, bacterial and fungal infections. Photodynamic antimicrobial chemotherapy (PACT) has been efficacious in the management of periodontal infections, peri-implantitis, endodontic infections and oral bio-films formation. The absence of genotoxic and mutagenic effects and no risk of developing resistance to its antimicrobial action made its use important. Photodynamic therapy is limited to superficial lesions at present. However, in future a deeper effect can be achieved by the developments in this technique. This review gives a general summary of the mechanism and clinical applications of photodynamic therapy.