Combined endodontic treatment: microbiological aspects by using scanning electronical microscopy

Aim. To determine possible alternative algorithms for root canal disinfection through the combined use of chemical and physiotherapeutic irrigation techniques under in vitro conditions.
Materials and methods. Single-root teeth removed according to orthodontic indications were used as a substrate for the formation of a biofilm. The formation of a mixed biofilm is carried out in several stages, successively introducing the following strains: Streptococcus sanguinis; Fusobacterium nucleatum; Porphyromonas gingivalis. Cultivation was carried out under fluid conditions under anaerobic conditions, for 168 hours. After the cultivation, the teeth were treated using: a solution of chlorhexidine bigluconate 2%; a solution of sodium hypochlorite 3%; photodynamic exposure with Fotoditazin photosensitizer; 1.0% sodium hypochlorite solution in combination with photodynamic exposure. The results were evaluated using scanning electron microscopy.
Results. The results of scanning electron microscopy revealed differences between the samples of the control group and the comparison group. The number of bacterial cells was significantly lower in the comparison group than in the control group, however, in all samples, the presence of microbial biofilm sites was noted with varying degrees of severity. In the samples where standard concentrations were used, there was a change in the ultrastructure of the walls of the dentine tubules with its partial destruction and obturation by its own fragments of the walls with the presence of microbial cells. When using the photodynamic effect of destruction was not observed. The microbial landscape had a similar species composition, and more fragments of biofilm and individual cells were observed only in the case of PDT without a combination with an antiseptic.
Conclusions. A comprehensive approach to endodontic treatment using photodynamic therapy together with antiseptic solutions in low concentrations allows us to achieve the best effect of pathogen eradication in comparison with the standard chemomechanical method.

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