1. MICROBIOLOGY
ORAL MICROBIOLOGY
AYDIN ÇÖL

2. Directions
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Write name and date on top
Write only the answers of the questions on the right
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3. 5 min
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5. Introduction to oral microbiology
The oral cavity is the most complex and the most accessible microbial ecosystem of the human body.
The teeth,
gingivae (gums),
tongue,
throat and
buccal mucosa (cheeks)
all provide different surfaces for microbial colonization.

6. The constant production of saliva and intermittent provision of sugars and amino acids from ingested food provides nutrients for microbial growth.
The human oral cavity is home to about 700 identified species of bacteria.
This number will probably turn out to be closer to 1000 in the future, when all taxa and phyla have been recorded.
It is also home to at least 30 species of fungi (mainly of the genus Candida), several species of protozoa (which graze on the bacteria for food), and various intracellular viruses.

7. Generalizing, in a single subject it is usual to find between 20 – 50 species of bacteria at healthy oral sites.
At diseased sites there is a tendency for higher numbers of different species to be present, perhaps 200 or more.
The organisms present in the oral cavity are a mixture of commensals
and pathogens.
A commensal microorganism is defined as one that lives on or within a host but does not cause any apparent disease.

8. Many of the cultivated bacteria present in the mouth probably
contribute to oral diseases to a greater or lesser extent, because these
diseases are almost always associated with polymicrobial infections
There are very few organisms in the oral cavity and nasopharynx that can be considered overt pathogens.
Streptococcus pyogenes (Group A Streptococcus),
Streptococcus pneumoniae(Pneumococcus),
Neisseria meningitidis(Meningococccus) and
Haemophilus influenzae
all reside within the nasopharynx and have the potential to cause life-threatening diseases.

9. Etiology of the major bacterial diseases in the oral cavity
Mutans streptococci and
other acidogenic bacteria
fermentable carbohydrate
organic acids
dissolution of tooth structure
(enamel, cementum, dentin)
CARIES

10. Reversed by plaque removal
GINGIVITIS
Reversed by plaque removal
accumulation of dental plaque gingival inflammation
exacerbated by systemic factors
e.g. pregnancy , puberty

11. Colonization of subgingival regions by specific groups of organisms
PERIODONTITIS
Colonization of subgingival regions
by specific groups of organisms
expression of virulence factors
e.g. proteases, leukotoxin
Destructive immune responses
Loss of periodontal tissue including
gingiva, periodontal ligament
and alveolar bone

12. Important oral diseases, their manifestations and the major microorganisms involved.
Caries
Description
Decay (loss) of tooth enamel (dental caries) or dentin (dentinal caries), or root dentin (root aries)
Microorganisms implicated
Streptococcus, Lactobacillus, Actinomyces (root caries)

13. Important oral diseases, continued
Gingivitis
Description
Redness and swelling (inflammation) of the
gingival tissues (gums)
Microorganisms implicated
Actinomyces, Fusobacterium, Bacteroides, Prevotella

14. Important oral diseases, continued
Pulpitis
Description
Infection of the pulp, inflammation around the apex of the root, leading to abscess formation (periapical granuloma)
Microorganisms implicated
Fusobacterium, Dialister, Peptostreptococcus, Porphyromonas

15. Important oral diseases, continued
Periodontitis
Description
Inflammation and either rapid (aggressive,
either generalized or localized) or slower
(chronic) destruction of the tissues supporting the tooth
Microorganisms implicated
Aggregatibacter (localized), Porphyromonas, Treponema, Tannerella, Fusobacterium,
Prevotella

16. Important oral diseases, continued
Implantitis
Description
Staphylococcus, Pseudomonas,
Porphyromonas, Prevotella
Microorganisms implicated
Infection and destruction of tissues surrounding a dental titanium implant

17. Important oral diseases, continued
Halitosis
Description
Oral malodor
Microorganisms implicated
Fusobacterium, Porphyromonas, Prevotella, Treponema, Eubacterium

18. Important oral diseases, continued
Pharyngitis
Description
Redness and inflammation of the pharynx
Microorganisms implicated
Group A Streptococcus, Neisseria,
Haemophilus, Coxsackie A virus

19. Important oral diseases, continued
Tonsillitis
Description
Infection and inflammation of the tonsils
Microorganisms implicated
Group A Streptococcus, Haemophilus

20. Important oral diseases, continued
Leukoplakia
Description
White patches on the buccal mucosal epithelium or tongue
Microorganisms implicated
Candida, human papilloma virus (HPV)

21. Important oral diseases, continued
Stomatitis
Description
Reddening and inflammation of the oral mucosa
Microorganisms implicated
Candida albicans, Candida tropicalis, other Candida species

22. Important oral diseases, continued
Actinomycosis
Description
Hard swelling (cyst) within the gums
Microorganisms implicated
Actinomyces israelii

23. Important oral diseases, continued
Cold sores
Description
Surface (superficial) red, dry lesions close to the lips
Microorganisms implicated
Herpes simplex virus (HSV)

24. QuestIons?

25. Have a wonderful
day
Thank you for being my students!