Hard tissue pathology (microbiology of caries)

Question 1

what is caries the process of?

Answer 1

Caries is the process of demineralisation of hard dental tissue by acid

Question 2

how is the acid produced

Answer 2

as a waste product by bacteria

Question 3

Dental caries is a what associated disease?

Answer 3

plaque associated

Question 4

For caries to occur there are 4 elements that are required which are?

Answer 4

Tooth
Time
Plaque bacteria
Sugar

Question 5

Evidence shows that the following3 are more important in causing enamel and root surface caries which are?

Answer 5

Streptococcus Mutans
Lactobacillus species
Actinomyces species

Question 6

how can streptococcus mutans cause caries?

Answer 6

they rapidly metabolise sugars to lactic acid demineralisation more rapidly than other plaque bacteria
Has ability to initiate and maintain microbial growth in low pH sites.
Produces extracellular polysaccharides from sucrose, which encourage further microbial attachment to plaque.
Produce intracellular polysaccharides which can act as food store for use when dietary carbohydrate low.
Streptococcus mutans are therefore strongly implicated in aetiology of early demineralization particularly in fissure caries, but also in root surface caries.
Strains of S. mutans are more pathogenic than others and therefore vary in their potential to produce caries.

Question 7

how are lactobacillus related to caries?

Answer 7

Lactobacilli are not thought to be involved in the initiation of caries, but more in the progression deep into enamel and dentine.
Therefore related to the progression of the carious lesion.
Produce lactic acid
Increase in number in carious cavities
Increase in number in saliva when caries present

Question 8

how are actinomyces related to caries?

Answer 8

Actinomyces form a major part of the microflora of plaque, particularly interdentally.

Actinomyces viscosus is associated with development of root surface caries, however, stronger association between s. mutans and lactobacilli.

Question 9

how is Veillonella related to dental caries?

Answer 9

found in most supragingival plaque samples

Protective plaque bacteria – metabolise lactic acid produced by other micro-organisms into less cariogenic, organic acid.

Unable to metabolize carbohydrates, they produce weaker, less cariogenic acids from lactates (produced by plaque bacteria)

Question 10

what type of acid does streptococcus mutants produce?

Answer 10

lactic acid