CHAPTER 28:Antimicrobial Photodynamic Therapy: A Decade of Development and Clinical Study

This chapter focuses on recent clinical applications of antimicrobial photodynamic therapy (aPDT). The key attributes of aPDT include a wide therapeutic window, high efficacy against polymicrobial biofilms, avoidance of the resistance issues that plague antibiotic usage, potent anti-inflammatory effects and the activation of both the innate and adaptive arms of the immune system. Clinical applications for chronic adult periodontitis, refractory rhinosinusitis and staphylococcal nasal decolonization are presented in detail. The chapter demonstrates how a Methylene Blue-based sensitizer along with relatively low-power activation can provide the clinician with an alternative to the standard of care, including mechanical debridement, surgery, empirical antibiotic coverage and combinations of steroids and antibiotics in both systemic and topical administration. The treatment time is short, adverse effects are minimal to non-existent and no patient compliance either before or after therapy is required. The clinical hardware is relatively inexpensive due to the ongoing evolution of diode lasers, light-emitting diode arrays and low-loss, high-performance plastic optical fibers. In particular, the ongoing emergence of multidrug-resistant organisms and the absence of resistance induction by aPDT implies that the technique faces a bright future as a clinical modality and should be further developed.