Comparison of Red-Complex Bacteria Between Saliva and Subgingival Plaque of Periodontitis Patients: A Systematic Review and Meta-Analysis

Abstract

The development of periodontitis is associated with an imbalanced subgingival microbial community enriched with species such as the traditionally classified red-complex bacteria (Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola). Saliva has been suggested as an alternative to subgingival plaque for the microbial analysis due to its easy and non-invasive collection. This systematic review aims to determine whether the levels of red-complex bacteria assessed using saliva reflect those in subgingival plaque from periodontitis patients. The MEDLINE, EMBASE, and Cochrane Library databases were searched up to April 30, 2021. Studies were considered eligible if microbial data of at least one of the red-complex species were reported in both saliva and subgingival plaque from periodontitis patients, based on DNA-based methods. Of the 17 included studies, 4 studies used 16S rRNA gene sequencing techniques, and the rest used PCR-based approaches. The detection frequency of each red-complex species in periodontitis patients was reported to be > 60% in most studies, irrespective of samples types. Meta-analyses revealed that both detection frequencies and relative abundances of red-complex bacteria in saliva were significantly lower than those in subgingival plaque. Moreover, the relative abundances of all 3 bacterial species in saliva showed significantly positive correlation with those in subgingival plaque. In conclusion, current evidence suggests that one-time saliva sampling cannot replace subgingival plaque for microbial analysis of the red-complex bacteria in periodontitis patients. Given the positive microbial associations between saliva and subgingival plaque, a thorough review of longitudinal clinical studies is needed to further assess the role of saliva.

Prevotella genus and its related NOD-like receptor signaling pathway in young males with stage III periodontitis

“…Plaque bacteria and their products are essential initiating factors for periodontitis and directly and indirectly participate in the whole process of this disease (Lunar Silva and Cascales, 2021). A specific group of bacteria defined as "the red complex, " which includes P. gingivalis, B. forsythus, and T. denticola, is strongly related to the pathology of periodontitis (Jiang et al, 2021), while bacteria in "the orange complex, " including P. intermedia, P. nigrescens, P. micros, and F. nicleatum (Miranda et al, 2019). When the periodontium is healthy, the number of oral bacteria is low and mostly include aerobic or facultative Gram-positive streptococci and actinomycetes (Aas et al, 2005).…”

Volatile sulfide compounds and oral microorganisms on the inner surface of masks in individuals with halitosis during COVID-19 pandemic

“…Among these, proteolytic obligate anaerobes and Gram-negative species are responsible for odorous compounds that can cause halitosis 15 . The development and progression of periodontitis are related to an imbalanced oral microbial community enriched with red-complex Gram-negative bacteria, including Pg, Td, and Tf 21 . Sigmund Socransky introduced the red complex concept in 1998, and periodontal diseases, along with poor oral hygiene and tongue coating, have been found to be common in people with halitosis 15,22,23 .…”

Host mRNA Analysis of Periodontal Disease Patients Positive for Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans and Tannerella forsythia

“…In a recent meta-analysis, Jiang Y et al made a comparison between saliva and subgingival plaque using 16S rRNA gene sequencing techniques. They revealed that both the detection frequencies and relative abundances of red-complex bacteria in saliva were significantly lower than those in subgingival plaque, leading to the conclusion that there is a need for further longitudinal clinical studies to evaluate the role of saliva [ 69 ].…”