Oral Microbiome


The term “microbiome” was coined by nobel prize laureate Joshna Lederberg   to signify the ecological community of commensal symbiotic and pathogenic micro- organisms. It includes bacterial, fungal, few protozoa and virus.

Human fetus inside the uterus is sterile ,but after passing through the birth canal it acquires vaginal & fecal micro-organisms. The colonization of the oral cavity also starts about the time of birth(1).In general  microbiota leaves the harmony with the host ,but under specific conditions (increased mass or pathogenicity, reduced host response) disease may occur(1)

Based on physical & anatomical criteria ,oral  microbiota has different habitats ,including teeth, gingival sulcus, dorsal and ventral surface of tongue, hard and soft palate ,periodontal ligament ,tonsils.(1)

There are various factors influencing the microbiological environment.


Saliva is clear. slightly acidic, exocrine secretion ,contains oral bacteria and food debris .dislodgement of micro-organisms from colonizing aggregation in various location of oral cavity ,contributes the micro flora of the saliva .

Adult human saliva is reported to contain approximately 6 billion (6*10 9)per millimeter including Streptococci, Peptostreptococci, Veillonella,Cornybacterium,Neisseria,Nocardia,Fusobacterium,Bacterodes,Lactobacilli,Actinonomyces,Spirochetes(2)


Systemic diseases with increased inflammation are frequently linked to increased risk of periodontal diseases both type 1 and type 2 diabetes mellitus affects periodontal ligament of children and adult, shows greater inflammatory response in same bacterial  load of normoglycemic individuals .Increased   glucose level, increased glycation products and enhanced cytokine expression less effective in bacterial killing ,Increases osteoclastic activity and decreases  osteoblasts  production results in bone destruction(4)


Periodontal disease is capable of  predisposing individuals to cardio vascular disease ,given that gram negative species involved in dectecable level of pro -inflammatory  cytokines. Microbes like Streptococcus sanguis, Porphromonas gingivalis  reduces platelet aggregation ,which leads to thrombus formation, Pporphyromonas gingivalis can actively adhere into fetal bovineheart endothelial cells,release proteolytic enzymes which active factor  X , prothrombin  protein promoting a thrombotic tendency and conversion of fibrogen into fibrin and results in intravascular clot formation(5)


Periodontal disease are initated by bacteria that accumulate in a bioflim on the tooth surfaces and affect the adjacent periodontal tissues, disease such as rheumatoid arthiritis (RA), systemic lupus erythematousus(SLS) increased suspectibility to destructive periodontal disease ,although there is specific bacterial changes in each disease. Prevotella,  Selenomona s increased in RA , Selenomonas , Lactobacilli and  Prevotella  in SLE. Incresed  interlukin (IL)-17 is shown in SLE, RA and leukocyte adhesion deficiency and may cause change in oral microbiota (6)


1.microbiology of periodontal disease,cranzza book pageno-134.marc quirynen,win teughels,susan kinder hake,micheal G.newman.

2.oral microbiome more and more important in oral cavity and whole body.published on 2018 may 07.lugao , tiansongn Xn , Hang hang fegcuchen

3.reselience of oral microbiota in health :mechanism that prevent dysbiosis.B.T.rosier,P.D.marsh,A.mira

4. normal microbial flora of oral cavity .swapna majundar, ashok bhagat singh

5. the oral microbiota is modified by systematic disease.Journal of dental research 1-9 @ international American association for dental research 2018 D.T.graves.J.D.correa,T.A..silva

6.systemic disease caused by oral infection D.0.I :10-1128/CMR134.546,xiaojing Li, Kristin M, leif tronatad, ingas olsen

-Dr. G. Brindha (BDS) (Category: Dental Postgraduate Student), Salem


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