Fig. 1

The symbiont-the host-parasite relationship in the interaction between the microbial community within the subgingival dental plaque/biofilm and the host tissue response in inflammation. The factors given within the microbial community represent those that have claimed to be of importance for the activities within the biofilm as well as exposing the host tissues [14, 16, 57]. Similarly, the factors given within the host tissue response are those usually claimed to participate in the inflammatory reaction or as host defence factors against infections. The subgingival microbial community (dysbiosis) is under influence of local environmental factors such as saliva, oral hygiene, diet, pocket depth, antiseptics, antibiotics (local) and probiotics. The composition and activity within the dental biofilm are highly dependent on the assay systems used for evaluation e.g. culture, microscopy DNA-probes, quantitative polymerase chain reaction (qPCR) or next generation sequencing (NGS), biochemical methods and sampling techniques and strategies. The host tissue response of each individual is influenced by population, age, gender and genetics [16]. Environmental host factors such as medicals (cytotoxic drugs, systemic antibiotics) and smoking [17] as well as internal host factor such as systemic diseases and conditions (e.g. diabetes, obesity) [59], psychic stress/allostatic load [60] The two systems are highly dynamic and constantly fluctuating in activity and characterized by temporality. Abbrevations: NH₃ ammonia, H₂S hydrogen sulphide, LPS lipopolysaccharide, OSCN- hypothiocyanite, H₂O₂ hydrogen peroxide, AI-2 Autoinducer-2, CSP Competence-stimulating peptide, GCF Gingival crevicular fluid, IL interleukins (IL-1beta, IL-6, IL-8, IL.-18), TNFalfa Tumor necrotic factor alfa, IFNgamma Interferon gamma, MMP’s Matrix Metalloproteinases, ROS reactive oxygen species, CRP C-reactive protein