Generation and Role of Reactive Oxygen and Nitrogen Species Induced by Plasma, Lasers, Chemical Agents, and Other Systems in Dentistry

Figure 6

Mechanism of action of photodynamic antimicrobial chemotherapy (PACT). Photodynamic antimicrobial therapy is used as a periodontal treatment as an adjunct to scaling and root planing. When the laser or a light-emitting diode (LED) light source is used on the tooth/periodontal pocket, it causes a chain of events. The light source activates a photosensitizer, which reacts with oxygen to result in the formation of excited singlet oxygen (reactive species). They further form superoxides and peroxides which act on the bacteria and cause their elimination.