caries microbiology

Question 1

what type of bacteria cause endodontal infections

Answer 1

endogenous bacteria (bacteria already within body)

Question 2

give 2 examples of endodontic infection pathogens

Answer 2

porphyromonas endodontalis
enterococcus faecalis

Question 3

what is the oral microflora influenced by

Answer 3

host factors - systemic disease, antibiotic use, genetics
Diet - frequency of intake, chemical composition
Saliva - flow rate, pH
GCF - antimicrobial components
Microbial interactions - competition and co operation

Question 4

describe the microbiological process of periodontal disease

Answer 4

initial adhesion
colonisation
accumulation
complex community formation (disease causing)
dispersal (disease spreading)

Question 5

what are 2 important microorganisms in gingival health

Answer 5

veillonella
actinomyces

Question 6

name 2 microorganisms assosciated with gingivitis

Answer 6

actinomyces
prevotella intermedia

Question 7

name 3 microorganisms assosciated with periodontal disease

Answer 7

prevotella intermedia
porphyromonas gingivalis
tanerella forsythia

Question 8

microbial interactions
- competition vs co operation

Answer 8

competition - production of bacteriocins (kill other bacteria), metabolic products create environment for their species to thrive
co operation - work together for immune avoidance

Question 9

name 3 virulence factors of porphyromonas gingivalis

Answer 9

fimbriae: long aid attachment to host cells and short aid cell to cell autoaggregation
Gingipains: proteases which downregulates host immune response, activate MMPs and degrade host proteins to use as an energy source
atypical endotoxins - block host signalling via TLR - 4s
Biofilm formation: allows initiation of tissue destruction

Question 10

name 3 systemic conditions periodontal disease has been linked with

Answer 10

diabetes
rheumatoid arthritis
cadriovascular disease

Question 11

mycofilm

Answer 11

fungi providing scaffolding for bacteria to attach
e.g candida albicans and s.mucans

Question 12

name 4 risk factors for candia infection

Answer 12

(all centre around immunosuppresion)
- advanced HIV
- immunosuppresive drugs
- immunocompromised patients
- dialysis patients
- diabetes patients
- long term corticosteroid use
- broad spectrum antibiotics

Question 13

what are the 4 main types of oral candidosis

Answer 13

• pseudomembranous (thrush)
• erythmatous
• hyperplastic
• angular chellitis

Question 14

pseudomembranous oral candidosis appearance

Answer 14

white pronounced plaques that can be easily rubbed away but might leave a bleeding surface

Question 15

erythmatous candida appearance

Answer 15

red and angry looking

Question 16

newtons classification

Answer 16

scores denture stomatitis from I to III from least to most severe

Question 17

Denture stomatitis

Answer 17

common fungal infection
candida adhere and colonise acrylic fitting surface of denture and if not cleaned regularly this colony can grow and lead to candida infection

Question 18

what is the biggest risk if denture stomatitis infection is allowed to grow and persist

Answer 18

aspiration pneumonia

Question 19

signs and symptoms of denture stomatitis

Answer 19

inflamed mucosa under denture
burning sensation
discomfort
bad taste
- many patients will be unaware

Question 20

hyperplastic oral candidosis

Answer 20

assosciated with candidal leukoplakia and can be pre malignant
less pronounced and less plaque like than pseudomembranous, cant be scraped off
biopsy is required

Question 21

what is the key topical antifungal for treating angular chellitis

Answer 21

miconazole

Question 22

what are the 2 subtypes of candida most often found in the oral cavity

Answer 22

candida albicans
candida glabrata

Question 23

what antifungal should be given if candida infection caused by candida albicans

Answer 23

fluconazole
itraconazole

Question 24

what antifungal should be given if candida infection caused by candida glabrata

Answer 24

nystatin

Question 25

what structure does candida albicans have that candida glabrata does not which aids its pathogenicity

Answer 25

albicans can stretch to form long tail like hypha which can squeeze into small areas and aid invasion of tissues

Question 26

what is the link between chronic candida infection and oral cancer

Answer 26

if yeasts (candida) are given simple sugars they can metabolise these to alcohol
alcohol itself does not cause cancer instead its the acetaldehyde produced from alcohol breakdown that acts as a carcinogen and has the potential to cause DNA damage

Question 27

smear

Answer 27

scrape and view under microscope
e.g of pseudomembranous candidosis

Question 28

oral rinse

Answer 28

ask patient to swirl saline solution then grow on agar
e.g denture stomatitis

Question 29

swab

Answer 29

cotton swab to affected area of mucosa then grow on agar
(good for children as easy and quick)

Question 30

biopsy

Answer 30

small sample taken so histology can be analysed

Question 31

what type of agar can distinguish between candida species

Answer 31

chromogenic agar

Question 32

What are the 3 main components of fungal cell walls

Answer 32

chitin
mannoproteins
glucan

Question 33

azole antifungals

Answer 33

inhibit ergosterol synthesis which is present in fungal cell membranes
e.g fluconazole
mitraconazole

Question 34

polyene antifungals

Answer 34

bind directly with ergesterol on cell membrane and cause pores to open up. This sees leakage of cytoplasmic membrane and cell death
e.g nystatin

Question 35

what is a good first line option for treating oral candida infections

Answer 35

chlorhexidine mouthwash
antifungal and antibacterial

Question 36

echinocandin antifungals

Answer 36

inhibit enzyme that is vital for cell wall formation - results in cell death
e.g caspofungin