Advances in Photodynamic Therapy Research first presents some basic concepts about the photodynamic diagnosis and treatment of neoplastic diseases. Some important considerations to improve photodynamic therapy outcomes are addressed based on experiments employing different light sources and application protocols. The most important clinical applications of this technique include cancer therapy as well as the treatment of microbial infections. Photodynamic therapy is also a promising approach for the treatment of oral diseases such as periodontitis, oral leukoplakia, oral lichen planus, herpes simplex viral infections, and root canal infections. The authors summarize recent advances, mainly from their laboratory, on the development of conjugated polymer nanoparticles as advanced photosensitizers for photodynamic therapy and photodynamic inactivation applications.