Ecology of the microbiome of the infected root canal system: a comparison between apical and coronal root segments

Abstract

Aim To evaluate the microbial ecology of the coronal and apical segments of infected root canal systems using a complete sampling technique and next-generation sequencing. Methodology The roots of 23 extracted teeth with apical periodontitis were sectioned in half, horizontally, and cryo-pulverized. Bacterial communities were profiled using tagged 454 pyrosequencing of the 16S rDNA hypervariable V5–V6 region. Results The sequences were classified into 606 taxa (species or higher taxon), representing 24 bacterial phyla or candidate divisions and one archaeal phylum. Proteobacteria were more abundant in the apical samples (p<0.05), while Actinobacteria were in significantly higher proportions in the coronal samples. The apical samples harbored statistically significantly more taxa than the coronal samples (p=0.01), and showed a higher microbial diversity. Several taxa belonging to fastidious obligate anaerobes were significantly more abundant in the apical segments of the roots compared to their coronal counterparts. Conclusions Endodontic infections are more complex than reported previously. The apical part of the root canal system drives the selection of a more diverse and more anaerobe community than the coronal part. The presence of a distinct ecological niche in the apical region explains the difficulty of eradication of the infection, and emphasizes the need that new treatment approaches should be developed.

Molecular Identification of Cultivable Bacteria From Infected Root Canals Associated With Acute Apical Abscess

“…Endodontic therapy is essentially a debridement procedure and elucidating the microbial ecology of endodontic infections is a necessary step to understand the necessity of microbial control during all phases of endodontic treatment (1)(2)(3)(4).…”

“…only at the genus level) and even to misidentification, as one species can be assigned to another based on incomplete data. Furthermore, database does not usually include newly named species or as-yetuncharacterized species (4,10).…”

Microbiology of Oral Biofilm-Dependent Diseases: Have We Made Significant Progress to Understand and Treat These Diseases?

“…Primary endodontic infections are polimicrobial infections composed mainly of obligate anaerobes, with a high prevalence of members of the phyla Firmicutes and Bacteroidetes. Differences in composition are also observed along the root canal, with a higher microbial diversity in the apical region [101]. Survival of microorganisms in the apical RCS and/or outside the apical foramen may lead to treatment failure and the establishment of persistent infections.…”

Endodontologie in beweging: nieuwe concepten, materialen en technieken 4. Wortelkanaaldesinfectie anno 2015

“…Een wortelkanaalinfectie is complex van samenstelling. Met behulp van moderne moleculair biologische technieken, waarbij het DNA van micro-organismen wordt geanalyseerd, is duidelijk geworden dat een endodontische infectie uit meer dan 600 bacteriesoorten kan bestaan (Özok et al, 2012;Vengerfeldt et al, 2014). Ook is bekend dat bacteriën als clusters ingebed in zelfgeproduceerd slijm en gehecht aan een oppervlak (biofi lms) voorkomen.…”