Photodynamic Therapy in Endodontics

Abstract

Commonly used irrigants do not always eradicate the entire microbial flora in infected root canals. Therefore, several other strategies, such as photodynamic therapy (PDT) have been developed. Photoactivated disinfection is based on the interaction of a photosensitive antibacterial agent and a light source. It uses a nontoxic dye named photosensitizer (PS) and lowintensity visible light. In oxygen presentation, these combine to produce some cytotoxic species. The PS molecules attach to bacteria membrane. Irradiation with a specific wavelength of the light may lead to the production of singlet oxygen, resulting in rupture of the microbial cell wall. There are several applications for PDT in dentistry. A successful periodontal treatment is based on elimination of bacteria from the infected area. Phenothiazinium PSs have been shown to be highly effective and safe for this purpose. However, scaling/root planing should be performed before the PDT. While performing the PDT, PS should be first injected in the periodontal pocket and allowed to pigment. Then, the special fiber should be inserted 1 mm short of the pocket base and lased. Photodynamic therapy has also been used to disinfect caries dentin before restoration, disinfecting oral tissues before or during surgical procedures, treating denture stomatitis, and treating oral candidiasis in immunocompromised patients. Photodynamic therapy can be used in combination with mechanical instrumentation and chemical antimicrobial agents, such as sodium hypochlorite, too. The purpose of this study was to review historical perspective, mechanism of action, and applications of PDT in dentistry and especially in endodontics was reviewed. Furthermore, the effects of PDT on dentin bonding and endotoxin are discussed.Clinical significance: Photodynamic therapy has been advocated to increase the disinfection level of the root canal system.

Photodynamic therapy in endodontics: literature review.

“…These are highly reactive chemical species that bind to the bacterial membrane and damage proteins, lipids, nucleic acids and other microbial cellular components. It is important that the light source is absorbed by the dye so that the PDT is effective in making cells unviable (8,10,16,17).…”

“…The photosensitizer is a chemical sensitive to light, the use of photosensitizers for photosensitizing infected tissues can allow the absorption of bacterial cells and irradiation to tissues and result in the destruction of both infected tissues and bacteria (17). The desired properties of an excellent photosensitizer include: low cytotoxicity, short photosensitivity, simplicity in formulation, reproducibility, high stability and high affinity, and penetration into bacterial cells instead of healthy tissues (selectivity) (14).…”

Using Photodynamic Therapy in Root Canal System – A Literature Review

“…Light-induced inactivation of microorganism is defined as PDT [11]. The use of photosensitizer (PS), that is, photo activated dye, at a specific wavelength gets activated by light in the presence of oxygen [12,13].…”

Terapia fotodinâmica na endodontia: revisão de literatura

“…Esses são espécies químicas altamente reativas que se unem à membrana das bactérias e danificam proteínas, lipídeos, ácidos nucléicos e outros componentes celulares microbianos. É importante que a fonte de luz seja absorvida pelo corante para que a PDT seja efetiva na inviabilização de células (8,10,16,17).…”

“…O fotossensibilizador é um produto químico sensível à luz, o uso de fotossensibilizador para a fotossensibilização de tecidos infectados pode permitir a absorção as células bacterianas e a irradiação para os tecidos e resultar na destruição de ambos os tecidos infectados e bactérias (17). As propriedades desejadas de um ótimo fotossensibilizador incluem: baixa citotoxidade, fotossensibilidade de curta duração, simplicidade na formulação, reprodutividade, elevada estabilidade e alta afinidade, e penetração em células bacterianas em vez de tecidos saudáveis (seletividade) (14).…”