Periodontitis - experimental evidence

Question 1

why is it difficult to do epidemiological studies on periodontal disease?

Answer 1

Hard to get evidence

Can do gingivitis studies in a simulated environment as no permanent damage to patients.

However can’t ethically with periodontitis due to irreversible damage

Question 2

what do immunological studies tell you?

Answer 2

Antibodies can tell you the stage of disease
The immune response amplifies the damage of the bacteria and promotes their growth

Question 3

what bacteria are in chronic periodontitis?

Answer 3

Porphyromonas gingivalis (red)
Fusobacterium nucleatum (orange)
Spirochaetes

Question 4

what bacteria are in rapidly progressing periodontitis

Answer 4

Porphyromonas gingivalis (red)
Fusobacterium nucleatum (orange)
Prevotella intermedia (red)

Question 5

what did moore and moore microbiological studies find?

Answer 5

Some bacteria present in health and disease
Disease associated with increasing levels of
Aggregatibacter
Eubacterium
Fusobacterium
Prevotella
Poryphymonas

Question 6

what did sokransky’s microbiological studies find?

Answer 6

Used DNA hybridation to form groups of bacteria (disease complexes) that are associated with disease. (they act co-operatively) -> red and orange disease complexes

Difference between supra and subgingival plaque species: sub-gingival has less Streps and actinomyces species but more GNABs

Question 7

what are red complex bacteria associated with?

Answer 7

active pockets of periodontitis

Question 8

what bacteria are in red complexes?

Answer 8

Porphyromonas gingivalis
Tannerella forsythia
Treponema denticola

Question 9

what are orange complexes associated with?

Answer 9

Linked to increase plaque in periodontitis

Question 10

what bacteria are in orange complexes?

Answer 10

Fusobacterium
Prevotella nigrescins
Prevotella intermedia

Question 11

what bacteria are part of the bacteroids group that can destroy eukaryotic cells -> B haemolysis ?

Answer 11

prevotella species (orange)
porphyromonas species (red)
tanerella forsythia (red)
(streptococci)

Question 12

which bacteria produce black pigment in culture on a petri dish?

Answer 12

prevotella species (orange)

take up reactive oxygen species, hence the dark colour

Question 13

how are black pigmented bacteria treated with blue light?

Answer 13

These bacteria have porphyrins on their surface which get excited by the blue light and release reactive oxygen species which destroy lipids, proteins and nucleic acids

Question 14

what are curtis et al’s 3 Cs?

Answer 14

community change
microbial complexes
commensal involvement

Question 15

what does the non-specific plaque hypothesis relate to?

Answer 15

relates to gingivitis as plaque is cause

Question 16

what does the specific plaque hypothesis relate to?

Answer 16

linked to periodontitis through red and orange complexes

Question 17

what does the ecological plaque hypothesis relate to?

Answer 17

linked to periodontitis through shift in bacterial community during disease

Question 18

what are key stone pathogens?

Answer 18

are bacteria that have a larger effect on the disease process -> if increase even a little bit have a big effect

Question 19

in key stone pathogens what does LPS/inflammation do?

Answer 19

induces osteoclast proliferation (bone matrix removal)

Question 20

in keystone pathogens what do capsular polysaccharides do?

Answer 20

stimulate osteoblast apoptosis (stops bone production and calcification)