Prevalence of red and orange microbial complexes in endodontic-periodontal lesions: a systematic review and meta-analysis

Objective This systematic review assesses the prevalence of microbial complexes in endodontic-periodontal lesion. Materials and methods Nine databases were searched through August 2020. Experts were consulted to indicate additional studies. Studies were blindly selected by two reviewers based on pre-defined eligibility criteria. Studies that evaluated the prevalence of microbial orange and red complexes among patients with endodontic-periodontal lesion were considered eligible. Risk of bias was assessed using the Joanna Briggs Institute Critical Appraisal Checklist for Studies Reporting Prevalence Data. Results From 572 articles found on all databases, 11 clinical studies were finally included. The following microorganisms were investigated: P. gingivalis , T. forsythia , T. denticola , F. nucleatum , F. periodonticum , P. micra , P. intermedia , P. nigrescens , S. constellatus , C. gracilis , C. rectus , C. showae and E. nodatum. Considering the orange complex, P. micra , E. nodatum and S. constellatus were prevalent in both root canal and periodontal pockets. P. gingivalis and T. forsythia belonging to the red complex were prevalent only in periodontal pockets. The red complex microorganisms were not found very frequently in root canal. Conclusions There is a similarity between the microbiome of root canal and periodontal pockets, with prevalence of the three microorganisms of the orange complex. Two microorganisms from the red complex were prevalent only in periodontal pockets. Clinical relevance The prevalence of specific microorganisms in endodontic-periodontal lesion is important to understand the microbiological profile of the patients involved and to correlate it with possible clinical and repair conditions of this pathology.