Relationship Between Oral Microbiota and Periodontal Disease: A systematic Review
Periodontal disease has long been associated with the “red complex” bacteria, however, a recent systematic review discovered new bacterial species possibly associated with the onset and progression of periodontal disease. This same systematic review also highlighted the fact that periodontal disease probably is not caused by a specific bacterium, rather it is caused by changes in the levels of the bacteria in the oral microbiome. This systematic review prompted another systematic review that published September 2018 in the European Review for Medical and Pharmacological Sciences the aim was to analyze studies published in the last five years that focused on changes in the oral microbiota and periodontal status in humans.1
Eleven controlled clinical trials were included in the review. The selected studies included adult patients in the age range of 24 to 56 years of age with periodontal disease. Healthy patients not affected by periodontal disease were used as the control group. In three of the CCTs a third group of patients were evaluated that were affected by gingivitis.
According to the author’s analysis, 3 species/genera were identified as new periodontal pathogens with strong evidence. They include Desulfobulbus spp., Filifactor alocis, and TM7 spp. Additionally, a moderate association with other microorganisms and periodontal disease was found in the study. These include Eubacterium spp., Fretibacterium spp., Parvimanos micra, Peptostreptococcus spp., Porphyromonas endodontalis, Selenomonas sputigena, Synergistes spp., and Treponema socranskii.
Another emerging, yet new technique being applied to identifying periodontal pathogens that was often used in this analysis is metagenomics. During the search for studies to include in this review, over the past 5 years, 635 used metagenomics to determine the composition of the human microbiota more accurately. This technology has helped identify species that were not previously cultivated through standard microbiology.
This review concedes there are a couple of limitations. First, the review only confirms or adds evidence, but does not give the necessary association of the newly discovered pathogens with the etiology of periodontal disease. Another limitation included by the authors states the evidence that microorganisms found in higher levels in patients with the disease compared to those with healthy gingiva may not be sufficient to determine if the microorganisms initiated the disease process or if the conditions of the inflammatory environment were favorable for onset and progression.
The authors conclude, “The results of this systematic review support high evidence for the association of 3 new species/genera with the etiology of periodontitis. This data would be useful to guide future investigations on the actual role of these new pathogens in the onset and progression of this disease as well as on the identification of other pathogens helping to understand the mechanisms that regulate their association and to develop preventative and therapeutic strategies for the control of the disease.”
Were you aware of the discovery of these novel pathogens associated with periodontal disease? Does this information further emphasize the complexity of periodontal disease and the ongoing discoveries associated with it? Are you familiar with metagenomics as a tool for the discovery of new pathogens in oral diseases? Does this information help you understand the importance of continuing education, as we are constantly learning new things that apply to dentistry?
Patini R, Staderini E, Lajolo C, et al. Relationship between oral microbiota and periodontal disease: a systematic review. Eur Rev Med Pharmacol Sci. 2018;22(18):5775-5788. doi:10.26355/eurrev_201809_15903