An in vivo evaluation of microbial diversity before and after the photo-activated disinfection in primary endodontic infections: Traditional phenotypic and molecular approaches

Publication date: June 2018
Source:Photodiagnosis and Photodynamic Therapy, Volume 22
Author(s): Maryam Pourhajibagher, Abbas Bahador
BackgroundIt is essential to identify the root canal microbial diversity and count. This is due to the polymicrobial nature of the primary endodontic infection that is associated with the microbial diversity and increased resistance to the antimicrobial agents. Photo-activated disinfection (PAD), also known as antimicrobial photodynamic therapy, is a new promising non-antibiotic approach, studied to prevent microbial resistance and treatment failure.Materials and methodsIn this study, we investigated the effect of PAD on reduction of microbial diversity and count, related with primary endodontic infections. Microbial specimens were collected before PAD from patients infected with the primary endodontic infection. PAD with toluidine blue O (TBO), in combination with diode laser, was performed on infected root canals. Resampling was carried out on the root canal after PAD, and microorganisms were identified by classical microbiological tests using biochemical and analytical profile index (API ^® 20A) assays and nucleic acid approaches.ResultsFrom the 36 subjects studied before TBO-PAD, 187 cultivable isolates from 14 different genera and 19 various microbial species were retrieved. Of the bacterial isolates, 45.4% were strict anaerobes including Veillonella parvula, Porphyromonas gingivalis, Propionibacterium acnes, Lactobacillus acidophilus, Campylobacter rectus, and Slackia exigua, in order of their frequency; 45.4% were facultative anaerobes; and 9.2% were microaerophilic bacteria (Aggregatibacter actinomycetemcomitans). This in vivo study revealed significant decrease in the microbial diversity and count of the infected root canal after TBO-PAD (P < 0.05); whereas P. gingivalis strains, the most resistance microorganisms, were recovered in 34% of the samples after TBO-mediated PAD (P > 0.05).ConclusionsTBO-mediated PAD is an effective in exhibiting efficient antimicrobial activity due to the substantial reduction of the microbial diversity and count in the primary endodontic infections.



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