2. Oral Flora

Question 1

Niche bacteria on ENAMEL: (when teeth erupt)

Answer 1

1. S. Mutans 2.S. Sanguis 3.Actinomyces spp

Question 2

Infant’s mouth is ______ at birth

Answer 2

Sterile

Question 3

Within a few hours of birth ___________________ is acquired.

Answer 3

Streptococcus salivarius (pioneer organisms)

• alters local environments in mouth and allow other bacteria to become established: eventually a climax community

Question 4

Stages of plaque formation

Answer 4

1. Clean enamel surface
2. 2secs: pellicle formation
3. 1min: pioneer bacteria (streptococcus sanguis)
4. 2hrs: microcolonies and extracellular polysaccharide
5. 2hrs onwards: biofilm development
6. 48hrs: mature plaque

*bacteria adhere to salivary pellicle first
* bacteria growth in biofilms => more difficult to eradicate (decreased susceptibility to antibiotics)

Question 5

What do we look at in the Genome sequencing of Oral Flora?

Answer 5

16s ribosomal RNA (16sRNA) subunit of bacterial ribosome