1. TITLE
THE HUMAN ORAL MICROFLORA
DR.ALI YALDRUM
DATE CLASS
22-03-12 1ST YEAR B.D.S
Friday, March 23, 2012

2. Lecture Objectives
At the end of this lecture students should be able to
Describe what is Human Microflora, Oral Microflora
Describe the importance of relationship between host and
microflora
Describe the diverse ecosystem of Oral Microflora
Describe the relationship between Oral Health and General
Health
Friday, March 23, 2012

3. WHAT IS NORMAL
MICROFLORA
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4. ‘is the aggregate of microorganism that reside on
the surface and in deep layers of skin, in the saliva
and oral mucosa, in the conjuctiva, and in the
gastrointestinal tracts.’
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5. Microflora is a misnomer, Researchers prefer
“Microbiota”
In a healthy human, internal tissues are devoid of
microorganisms
Brain, Blood, Muscles etc
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6. human body contains an estimated up of 1014 cells
only 10% are mammalian cells
90% are resident microbiota
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7. so what is oral microflora?
the microflora existing in the oral cavity is called as
oral microflora.
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8. FUNCTIONS OF ORAL
CAVITY
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9. COMMUNICATION
DIGESTIVE
SENSORY
GENERAL HEALTH
FIG.1
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10. ORAL
MICROFLORA
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11. The presence of nutrients, epithelial debris and
secretions makes the mouth a favorable habitat for
a variety of microorganisms
Streptococcus
Actinomyces
Prevotella
Fusobacterium
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12. The oral cavity represents a unique environment
succession of different ecological situations with
age
corresponds with the changes in the composition
of normal flora
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13. Haemophilus
Corynebacterium Neisseria
S. mitis S. mitis
Staphylococcus S. pneumoniae
Streptococcus
Actinomyces S. pyogenes
Fusobacterium S. salivarius
Porphyromonas
Candida
Streptococcus
FIG.2 SITE SPECIFICITY OF MICROBIAL ADHERENCE & COLONIZATION
Friday, March 23, 2012

14. at birth the oral cavity is composed solely of the
soft tissues of the lips, cheeks, soft palate and
tongue.
kept moist by the salivary secretions
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15. Friday, March 23, 2012

16. Friday, March 23, 2012

17. other species of streptococci adhere strongly to
gums and soft tissues
with the creation of gingival crevice area increases
the habitat for the variety of anaerobic species
complexity continues to increase with time
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18. RELATIONSHIP
BETWEEN HOST AND
MICROFLORA
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19. does not have a passive relationship
Beneficial association
contributes directly and indirectly to the normal
development
physiology
nutrition
defense
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20. Microbial colonization of all environmentally
accessible surfaces begins at birth
Exposed to wide range of microorganisms
Each surface is suitable for colonization by a
proportion of these microbes
Acquisition, selection and natural development of
diverse but characteristic microflora
Friday, March 23, 2012

21. Microbial flora exists in a harmonious relationship
with the host
if this relationship breaks down, disease can occur
in mouth this relationship is more prone to
breakdown than other parts of the body
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22. Breakdown is usually associated with
major changes to the biology of mouth from exogenous
sources
presence of the microorganisms at sites not normally
accessible to them
such microorganisms are termed as
‘opportunistic pathogens’
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23. Many oral microorganisms have capacity to
behave as opportunistic pathogens
Common clinical manifestations of oral microflora
imbalance are
Dental Caries
Periodontal diseases
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24. Dental Caries
‘is the dissolution of enamel or root surfaces
(demineralization) by acid produced primarily by
fermentation of carbohydrates in the diet by
bacteria colonizing the tooth surface (dental
plaque).’
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25. Periodontal diseases
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26. MICROBIAL
ECOLOGY
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27. DISEASE
SUSCEPTIBLE KEY ORAL
HOST MICROORGANISM
ENVIRONMENTAL
TRIGGER
THE INTERRELATIONSHIPS THAT LEAD TO ORAL DISEASE.
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28. SALIVA LIFESTYLE
ORAL
MICROBIAL
ECOLOGY
HOST
MICROFLORA
DEFENSES
INTER-RELATIONSHIPS THAT INFLUENCE THE MICROBIAL ECOLOGY OF THE MOUTH
IN HEALTH & DISEASE
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29. THE ORAL MICROFLORA
AND GENERAL HEALTH
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30. Newer evidence is accumulating suggests that
periodontal diseases have an impact on general
health.
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31. PRETERM LABOR DIABETES/ GLYCEMIC ENTER BLOOD STREAM
CONTROL
PRETERM LOW BIRTH TRANSIENT BACTERAEMIAS
WEIGHT
ATHEROSCLEROSIS
CORONARY HEART DISEASE
Friday, March 23, 2012

32. RESERVOIR FOR
HELICOBACTER PYLORI
OPPORTUNISTIC PATHOGENS
(GASTROESOPHAGEAL REFLUX)
ASPIRATION OF THESE PATHOGENS
INTO LOWER RESPIRATORY TRACT
CAN LEAD TO SERIOUS LUNG DETECTED IN DENTAL PLAQUE
INFECTION
LINKED WITH DEEP PERIODONTAL
POCKETS
CHRONIC GASTRITIS & STOMACH
ULCERS
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33. References
Philip D Marsh and Michael V Martin.”Introduction” in Oral Microbiology, 5th Edition. Churchil
Livingstone, 2009, pp 1-7.
Todar’s Online Textbook of Bacteriology, Internet: http://textbookofbacteriology.net/normalflora.html
[Mar 3, 2012]
Fig 1. http://www.shutterstock.com/pic-51438295/stock-vector-oral-cavity.html
Fig 2. “Complex Communities” in Oral Microbiology at a Glance, Wiley-Blackwell, 2010. pp 28.
Friday, March 23, 2012