Photonic real-time monitoring of bacterial reduction in root canals by genetically engineered bacteria after chemomechanical endodontic therapy

Abstract

Microbial infection plays an important role in the development of pulp necrosis and formation of periapical lesions. In vitro and in vivo research in this field, traditionally microbiological culture methods using paper point sampling and quantitative culture, faces difficulties in completely removing bacteria from the root canal system and analyzing sequential procedures. This study employed genetically engineered bioluminescent bacteria and a light-sensitive imaging system to allow real-time visualization of the infection. Ten extracted teeth incubated with P. aeruginosa were treated by mechanical instrumentation with K-files (#30 K-file, #35 K-file and #40 K-file) and chemical irrigation with sodium hypochlorite and hydrogen peroxide. Irrigation alone reduced the contamination in 18%; the first chemomechanical sequence (instrumentation with a #30 K-file + irrigation) provided 41% of reduction; the second sequence (#35 Kfile + irrigation) achieved 62%; and the complete therapy (#30 K-file + #35 K-file + #40 K-file + irrigation) achieved 93% of bacterial reduction. These results suggest that the endodontic treatment is dependent on the association of a chemical and mechanical approaches and that root canal enlargement improves bacterial reduction probably because the irrigation has more access to the apical third.

Dirty hands: photodynamic killing of human pathogens like EHEC, MRSA and Candida within seconds

“…Recently photodynamic treatment of microorganisms has been shown to be very effective in vitro as well as in vivo. [14][15][16][17][18][19] Photodynamic inactivation of microorganisms is based on the concept of positively charged photosensitizers that can attach and/or accumulate in or at the pathogen to induce irreversible damage upon light activation of the photosensitizer. 20,21 The absorption of light by a photosensitizer leads to the generation of reactive oxygen species such as singlet oxygen which induces irreversible oxidative damage of the pathogens during illumination.…”

Antimicrobial Efficacy of a Polymeric Chlorhexidine Release Device Using In Vitro Model of Enterococcus faecalis Dentinal Tubule Infection

“…Therefore, complete debridement and effective disinfection of the root canal space are considered essential for achieving predictable long-term success of nonsurgical endodontic treatment. The majority of infecting bacteria, together with their principal substrate of necrotic pulp debris, might be reduced significantly by chemomechanical instrumentation (2)(3)(4). However, this is not always achieved completely as a result of the anatomic complexity and diversity of root canals, as well as the subsequent limitations in access by instruments and irrigants (5)(6)(7).…”

Effects of antimicrobial photodynamic therapy and surgical endodontic treatment on the bacterial load reduction and periapical lesion healing. Three years follow up

“…PDT was highly effective in reducing bacterial load in an ex vivo model, in patients and even in a drug-resistant endodontic infection (14,15,19,20).…”

“…The combination of endodontic treatment and PDT has been shown as an effective approach in reducing bacterial load in in vitro and in vivo models (14)(15)(16)(17)(18)(19). However, in the literature there is no information about the effect of PDT associated with conventional endodontic surgery regarded to microbial reduction and even more if the noxious components produced on the periapical tissue could slow down the healing process.…”