Pathogenesis of periodontal diseases/Microbiology of periodontal disease

Question 1

classificaiton of bacteria and characteristics

Answer 1

1) Gram +
- dark purple/black
- thick cell wall made of peptidoglycan
2) Gram –
- 2 membranes (liposaccharide on the outside)
- stain pink/red

Question 2

polymicrobial infections

Answer 2

caused by interactions between 2 or more organusms leading to a disease
- sum of parts and their virulence factors cause disease not one in isolation

Question 3

subgingival plaque

Answer 3

heterogeneous
- those at the top can break off and iteract
Gram + layer attatched to hard tissue
Gram - overlying layer, anerobes and motile bacteria

Question 4

how to the bacteria work together in subgingival plaeu

Answer 4

swap nutrients between them

hydrogen perioxodie can be produced help released nutrients for the whole community

Question 5

what changes a quiecent sie to an acive one

Answer 5

change in host (age, immune status, environmental factors)

change in microbial challenege/community (type of organism, no particualr organisms, virelnce of the organisms)

Question 6

microbiome

Answer 6

all the bacteria in one particular environment at that specific time

Question 7

evidence for specific microbail aetiolgy

Answer 7

• high numbers of certain bacteria cultured from diseased sites and sequences identified in molecular studies
• can cause disease in certain animal models
• have demonstrable virulence factors (i.e. the factors can be modified to reduce diseae)
• potential pathogens present in health and in non diseased sights

Question 8

organisms in health

Answer 8

dominted by streptococci

actinomycetes

Question 9

P gingivalis structure

Answer 9

black pugmented anerobe well studies
toxic LPS
has pilli which can attatch to cell surfaces and other bactera
have proteses and gingipains (act as virulence actors

Question 10

T forsythia

Answer 10

anaerobe
gram - 
has surface s later
produces its own proteases and glycosidases
(degrade host glycoprotiens)

Question 11

T denticola

Answer 11

small thin spiral shaped bacterium

Question 12

how do groups of pathogens work together

Answer 12

differnt bactera = differnt virulence factors
combination is more liekly to cause disease
qualitiave max of pathogens determines disease progression

Question 13

dysbiosis

Answer 13

• concept of moving from a healthy community to a diseased community through environmental factors

Question 14

keystone hypothesis

Answer 14

• idea that these red complex organisms are able to shift the population from health to disease

Question 15

mechanisms of tissue damage

Answer 15

Combination of all the virulence factors and the bacteria which leads to the responses in toxicity

Question 16

what is necrotising ulerative giggivitus caused by

Answer 16

complex of 3 bacteria

Question 17

unculturables

Answer 17

some species can be seen in health and disease
function unkown