Photodynamic Therapy for the Treatment of Precancerous Lesions

Photodynamic therapy (PDT), also known as photoradiation therapy, phototherapy or photochemotherapy 1 is a minimally invasive surgical technique, whose application in dentistry is growing rapidly to target the premalignant and malignant disorders in the head and neck, gastrointestinal tract, lungs and skin with reduced levels of morbidity 2 . It 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 this energy from the activated photosensitizer to available oxygen results in the formation of toxic oxygen ions like free radicals and singlet oxygen 3 . These released reactive chemical ions can damage proteins, lipids and nucleic acids 3 . This review article lays emphasis on the basic aspects of photodynamic therapy and the various researches done regarding the treatment of premalignant lesions using this new therapeutic approach.