Photodynamic therapy: An adjunct to conventional root canal disinfection strategies

Abstract

Although chemical-based root canal disinfectants are important to reduce microbial loads and remove infected smear layer from root dentin, they have only a limited ability to eliminate biofilm bacteria, especially from root complexities. This paper explores the novel photodynamic therapy (PDT) for antimicrobial disinfection of root canals. The combination of an effective photosensitizer, the appropriate wavelength of light and ambient oxygen is the key factor in PDT. PDT uses a specific wavelength of light to activate a non-toxic dye (photosensitizer), leading to the formation of reactive oxygen species. These reactive oxygen molecules can damage bacterial proteins, membrane lipids and nucleic acids, which promote bacterial cell death. In, addition PDT may enhance cross-linking of collagen fibrils in the dentin matrix and thereby improving dentin stability. The concept of PDT is plausible and could foster new therapy concepts for endodontics. The available knowledge should enable and encourage steps forward into more clinical-oriented research and development. This article discusses PDT as related to root canal disinfection, including its components, mechanism of action, reviews the current endodontic literature and also highlights the shortcomings and advancements in PDT techniques.

Effects of Photodynamic Therapy on the Adhesive Interface of Fiber Posts Cementation Protocols

“…The mechanism of action of PDT occurs when a photosensitizing substance absorbs the photons from the irradiation source and their electrons enter an excitation state. Then, the energy is transferred to a specific substrate, forming reactive oxygen species (ROS) (mainly singlet oxygen), which irreversibly oxidize the cellular components causing bacterial death (11,13,14). However, it is still unknown whether the free radicals from the ROS release affect the adhesive interface between the dentin and fiber post cement after different cementation protocols, similar to the decontamination protocols using sodium hypochlorite.…”

Photodynamic therapy as an aiding in the endodontic treatment: case report

“…Several authors suggest that PDT is a safe and quick process of killing cells [4]. According to Singh et al [1], this therapy works to reduce the microbial load of RCS, as well as to improve dentin stability, provided there is a combination of an effective photosensitizer, adequate wavelength of light and ambient oxygen for its disinfecting action.…”

“…During PDT, a non-toxic photosensitizer (dye) placed directly at the destination site can be activated by means of an appropriate wavelength of visible light that causes damage to microbial components [8][9][10]. The transfer of energy from the activated photosensitizer to the available oxygen results in the formation of toxic oxygen species, known as singlet oxygen and free radicals, which are highly reactive and damage proteins, lipids, nucleic acids and other cellular microbial components [1,[11][12][13].…”

Antibacterial photodynamic therapy: overview of a promising approach to fight antibiotic-resistant bacterial infections

“…The other four studies provided compelling support for the bactericidal efficacy of APDT in localized dental infectious diseases [224][225][226][227][228]. Corroboratively, a recent systematic review yielded favorable results in regard to APDT for the treatment of infected root canals and called for a well-established clinical protocol [229]. Moreover, APDT has been suggested as an adjunctive treatment after standard endodontic treatment [225].…”