ICP4: Microflora of Dental Plaque

Question 1

Describe the 2 features of teeth that make it beneficial for microbial colonisation

Answer 1

• Hard

- Non Shedding

Question 2

Why are the pits and fissures of teeth good for microbial communities?

Answer 2

Offer protection from wider environment

Question 3

What are gingival crevice bathed in?

Answer 3

Gingival Crevicular Fluid

Question 4

How may bacteria on the tongue contribute to periodontal disease?

Answer 4

Back of the tongue can act as a reservoir for some gram negative anaerobes which may be present in periodontal diseases

Question 5

What structures of the tongue may act as habitats for microorganisms?

Answer 5

Papillary surfaces of the dorsum of the tongue

Question 6

What product found in saliva can influence aggregation and adhesion of bacteria to oral surfaces?

Answer 6

Glycoproteins in the saliva

Question 7

How can some microbial communities be physically removed?

Answer 7

By saliva and GCF and then swallowed

Question 8

How can saliva help remove microbial communities? 3

Answer 8

• Physical removal
• Production of lysozyme which hydrolyse peptidoglycan in bacterial cell wall
• Production of lactoferrin which competes with bacteria for iron

Question 9

What is the most prevalent bacteria in the adult oral cavity?

Answer 9

Streptococci

Question 10

What is the primary pathogen in aetiology of enamel caries in children and young adults?

Answer 10

Mutans Streptococcus

Question 11

What is the relevance of the Streptococcus oralis group?

Answer 11

Opportunistic pathogens isolated frequently from infective endocarditis

Have to be aware when extracting tooth as bacteria could enter blood

Question 12

What is the relevance of the Streptococcus milleri group?

Answer 12

Opportunistic pathogens important cause of purulent disease

Question 13

What is the relevance of Enterococcus?

Answer 13

Recovered in low numbers from several oral sites involved in root canal infections

Question 14

What forms a major portion of plaque microflora (especially at approximate sites)?

Answer 14

Actinomyces

Question 15

What is the relevance of the Eubacterium?

Answer 15

Anaerobic bacteria that are involved with:

• Periodontitis
• Necrotic dental pulp
• Infections of the head, neck and lung

Question 16

Name 4 microbes that are considered Gram-Positive and Filaments

Answer 16

• Actinomyces
• Eubacterium
• Lactobacillus
• Propionibacterium

Question 17

What is the relevance of Lactobacillus?

Answer 17

Involved in advanced caries lesion of enamel and root surface

Question 18

Name 2 microbes that are considered Gram-Negative cocci?

Answer 18

• Neisseria

- Veillonella

Question 19

What is the relevance of Neisseria?

Answer 19

Aerobic microbe that are among first colonisers of a clean tooth surface

Question 20

What is the relevance of the Veillonella?

Answer 20

Anaerobic microbe that play an important role in dental plaque and caries

Question 21

Where is haemophilia spp commonly found?

Answer 21

Common in saliva, on epithelial surfaces and in dental plaque

Question 22

Where in capnocytophag spp commonly found?

Answer 22

Found in sub-gingival plaque

Question 23

Where is actinomycetemcomitans (AA) commonly found?

Answer 23

Aggressive periodontitis

Question 24

Where is Simonsiella commonly found?

Answer 24

Epithelial Surfaces

Question 25

Where is Porphyromonas gingival commonly found?

Answer 25

Sub-gingival sites

Question 26

Where is Prevotella commonly found?

Answer 26

Isolated from dental plaque especially sub-gingival sites

Question 27

Where is Fusobacterium commonly found?

Answer 27

Gingival crevice and periodontal pockets

Question 28

What makes up the largest portion of the oral flora?

Answer 28

C.albicans