Bactericidal effect of photodynamic therapy

Photodynamic therapy (PDT) is a procedure whereby undesired tissue can be destroyed by the combined action of light, oxygen, and a photosensitizer. It is thought that a photosensitizer excited by light with a specific wavelength transfers its excitation energy to ground state oxygen molecules resulting in the generation of singlet oxygen. Singlet oxygen is a reactive oxygen species with high oxidative reactivity. Therefore, the reaction of singlet oxygen with cellular constituents can result in oxidative damage leading to cell death. Although PDT is mainly used in cancer treatment, several studies have shown that PDT also has antimicrobial properties. It has been proposed that the bactericidal effect of singlet oxygen generated by PDT could be used in clinical dentistry. Applications of PDT for the treatment of periodontitis and peri-implantitis, endodontic disease, and caries are now under study.