Caries Microbiology Bugs

Question 1

What are the 4 main groups of Streptococci species?

Answer 1

• mutans a - tooth surface (fissures)
• salivarius a - tongue
• anginosus ß - Dental plaque/ abscess
• oralis mitis a - tooth (biofilm/plaque)

Question 2

What is the Mutans Group Streptococci in relation to acid?

Answer 2

Acidogenic - produces acid at high rate from sugar

Aciduric - can withstand high acid conditions

Question 3

What are the Key proteins involved in attachment in S.mutans

Answer 3

Protein antigens

Glucosytransferase (GTF)

Glucan binding proteins (GBP)

Question 4

What are properties of Lactobacilli?

(Second most important group of bacteria in caries)

Answer 4

• Lactobacilli are Gram +ve
• Acidogenic & aciduric
• survive and reproduce under acid conditions ~ pH 5.5
• poor adhesion properties so late colonisers (EPS important)
• Adheres to dentine, over represented in advanced carious lesions

Question 5

What is the relation between Lactobacilli and dentinal caries?

Answer 5

Lactobacilli tend to increase as mutans Streptococci fall.

• High numbers (pure culture) in carious dentine
• Positive correlation between numbers of Lactobacilli and carious lesions
• Numbers isolated has been correlated with carbohydrate intake.

Question 6

What are Actinomyces?

Answer 6

Actinomyces are Gram +ve pleomorphic rods

• • Major proportion of microflora*
• Found in supra & subgingival plaque*

Question 7

What are 2 examples if Actinomyces found in the mouth and what are actinomyces usually assoiciated with?

Answer 7

• A. naesludii
• A. odontolyticus

Historically reported as associated with root surface caries