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ibms: lipids and carbs > Microbiology of dental caries 1 > Flashcards

Microbiology of dental caries 1 Flashcards

1
Q

Describe dental biofilm in health

A

They are diverse and made up of bacteria, fungi an viruses

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2
Q

How many species make up the dental biofilm?

A

can have as many as 300 different species in a single persons mouth

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3
Q

What is a microbiome ?

A

A Group of organisms

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4
Q

Where in the body is the most diverse biofilm found?

A

The gut

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5
Q

What can the dental boflm do in the mouth?

A

Can desquamate

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6
Q

What does desquamation do?

A

Reduces microbial load on the mucosal surfaces

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7
Q

What make dental biofilm unique?

A

It has non shedding surfaces

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8
Q

Give examples on non shedding surfaces in the mouth

A
  1. Teeth
  2. Dentures
  3. Implants
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9
Q

What do non shedding surfaces permit in the mouth?

A

They permit heavy biofilm formation if bacteria isn’t controlled

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10
Q

Give examples of some methods we can use to characterise the oral microbiome in health and disease

A
  1. Traditional culture
  2. Microscopy
  3. Molecular methods
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11
Q

Give some disadvantages of traditional culture tests

A
  1. Expensive
  2. Only 50-70% go he oral microbiota can be cultured
  3. Need to do multiple tests to identify and name the isolated organisms
  4. Laborious and time consuming
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12
Q

What di we do in traditional culture tests?

A

We grow the bacteria in jelly dishes with blood

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13
Q

Give some disadvantages of microscopy

A

Only cell morphology can be determined nothing else

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14
Q

Give some examples of molecular methods we can use to characterise the oral microbiome in health and disease

A
  1. PCR
  2. DNA-DNA hybridisation
  3. Humanoral microbiome identification microarray (HOMIM)
  4. High throughput whole genome sequencing
  5. DNA sequencing
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15
Q

Describe the process of PCR

A

Primer that is specific to a organism id added sample and if the organism is present in the sample it will be multipled and a tag is used to assess the presence of varying bacteria

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16
Q

What is the old standard now used to characterise the oral microbiome

A

Using whole genome sequencing

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17
Q

Give some examples of data bases that can be used in DNA sequencing

A
  1. Human microbiome consortium

2. Human oral microbiome database (HOMD)

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18
Q

How are microorganisms in dental biofilm organised?

A

Structurally and functionally organised

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19
Q

Give some key features of multi species biofilms

A
  1. Concerted and collaborative organisms
  2. Food chains
  3. Gradients present
  4. Matrix formation
  5. Cell-cell signalling
  6. Complex interactions occur create balance
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20
Q

Give some beneficial qualities of biofilms

A
  1. They exclude extrogenous microbes (Provide colonisation residence)
  2. Down regulation of potentially damaging po inflammatory host repossess
  3. Stimulates beneficial host responses
  4. Promotes host microbe balance
  5. Contributes to the enter salivary nitrate circulatory system
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21
Q

Name some healthy micro organisms

A
  1. Strep. Mitis/ oralis
  2. Actinomyces spp
  3. Haemophilus spp
  4. Neisseria spp
  5. Fusobacterium spp
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22
Q

Name some microorganisms found in caries

A
  1. Mutans streptococci

2. Lactobacilli

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23
Q

What do we mean when we say caries is a multifactorial disease

A

Theres several factor that al have to come into play for you to get caries

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24
Q

Give some factors needed to lead to the formation of caries

A
  1. Key oral microorganisms must be present
  2. Susceptible host present
  3. Environmental factors
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25
Q

Name some environmental factors that can cause dental caries

A
  1. Cariogenic diet
  2. Poor oral hygiene
  3. Low salary flow rate
  4. Fluoride availbilty
    5 Non specific virulence traits
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26
Q

What evidence is there or h role of microbes in the aetiology of dental caries?

A

The Gnotobiotic animal studies

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27
Q

What are the Gnotobiotic animal studies ?

A

They are tests done on germ free animals

We then introduce micro organisms to the germ free organism to assess the effect of the new microorganism on the animal

28
Q

What id the Gnotobiotic animal studies show?

A
  1. Some bacteria are more cariogenic the others
  2. Importance of fermentable sugars
  3. Disease can be transmitted from animal to animal
  4. Showed effective antimicrobials can prevent caries
29
Q

WHY can we not do germ free human studies?

A

For ethical reasons

30
Q

What type of tests can we carry out on humans?

A

Human epidemiology studies

31
Q

Name the 2 types of human epidemiology studies

A
  1. Cross sectional

2. Longitudinal

32
Q

Give some benefits of cross sectional studies

A

Cheap

Can look at a wide variety of people

33
Q

Give some disadvantages of cross-sectional studies

A

Only shows associations

34
Q

Give some benefits of longitudinal studies

A

They show a cause and effect relationship

35
Q

Give some disadvantages of longitudinal studies

A

They are expensive and take a long time o do as you follow group of people over several years

36
Q

Name some micro organisms implicated in dental caries

A
  1. Strep mutans
  2. Strep sobrinus
  3. Strep cricetus
  4. Strep rattius
  5. A neslundi
  6. A odontolyticus
  7. Lactobacillus spp
  8. Bifidobacterium
37
Q

Describe mutans streptococci

A
  1. Gram positive cocci/ short rods
  2. Found on hard non shedding surfaces
  3. Implicated I the initiation of caries
38
Q

What ae some f the difficulties when we associate micro organisms with dental caries?

A
  1. Disease occurs at sites with natural diverse microbiota
  2. Pathogens can be found at healthy. sites
  3. It is difficult to correlate microbiota to enamel status
  4. lesions can remineralise
  5. Pathogenic traits are relatively non specific
  6. Multi factorial nature of caries
39
Q

Where does disease first occur?

A

Just below the enamel surface which leads to a white spot lesion

40
Q

What have cross sectional studies shown us about the aetiology of caries

A

Mutans streptococci higher at caries sites
Theres an inverse relationship between MS and Step sanguines
Some sites with caries have no MS

41
Q

What have cross sectional studies shown us about fissure caries

A
  1. 71% of caries fissures had more than 10% mutant streptococci
  2. 70% of caries free fissures had no detectable mutans streptococci
42
Q

What have longitudinal studies shown us about the aetiology of caries

A

1 Confirms mutans streptococci present in high numbers at caries sites

  1. MS can occur after first signs of demineralisation
  2. Caries can occur in apparent absence of MS
  3. Other species also playa role incurs progression
43
Q

Name a lactate utilising micro organism that plays role in dental caries

A

Veilllonela Spp

44
Q

Describe veillonella

A
  1. Gam negative coccus
  2. Anaerobic
  3. Utilises lactic acid in plaque
45
Q

Name the streptococcus species that produces acid th fastest at ph5.5

A

S. Sobrinus

46
Q

Name some base generating species

A
  1. Strep Salivarius
  2. Strep sanguinis
  3. A. naeslundil
47
Q

Can mutans streptococci be detected I culture independent studies?

A

Not. unless they are present in high numbers

48
Q

Name different types of caries

A
  1. Nursing bottle caries

2. Root surface caries

49
Q

Name some bacteria present in high numbers in nursing bottle caries

A

Mutans streptococci

Lactobacilli

50
Q

Name some micro organisms found in infected dentine

A
  1. Mutans streptococci
  2. Lactobacilli
  3. Actinomycces spp
51
Q

Give some characteristics of cariogenic bacteria

A 
1. They transport sugar rapidly and produce acid rapidly 
2 Aciduricity (acid tolerant)
3. Extracellular polysaccharide 
4. Intracellular polysaccharide
52
Q

Describe the sugar transport system of mutans streptococci

A

Very rapid

Multiple systems

53
Q

At what pH do mutans streptococci produce acid?

A

pH 3.9-4.2

54
Q

Are mutans streptococci acid tolerant?

A

Yes they grow at pH 5.5

55
Q

What type of polysaccharides do mutans streptococci produce?

A

Soluble and insoluble extracellular polysaccharides

Intra cellular polysaccharides

56
Q

Describe the sugar transport system of lactobacilli

A

Rapid but little s known bout their transport system

57
Q

At what pH do lactobacilli produce acid?

A

pH 3.8-4.1

58
Q

Are lactobacilli `acid tolerant?

A

Ye stheyare very acid tolerant and grow at pH 5

59
Q

What type of polysaccharides do lactobacilli produce?

A

Low concentrations of extracellular polysaccharides and Intra cellular polysaccharides

60
Q

Describe the sugar transport system of actinomyces

A

Medium speed

Little is known about their transport system

61
Q

At what pH do actinomyces produce acid?

A

pH 4.4-.8

62
Q

Are actinomyces acid tolerant?

A

Medium tolerant

63
Q

What type of polysaccharides do actinomyces produce?

A

Medium concentration of extracellular polysaccharides

Produces intracellular polysaccharides

64
Q

Describe the sugar transport system of strep sanguinis

A

Medium speed

65
Q

At what pH do strep sanguinis produce acid?

A

pH 4.4-4.8

66
Q

Are strep sanguinis acid tolerant?

A

No they have a poor acid tolerance

67
Q

What type of polysaccharides do strep sanguinis produce?

A

Soluble and insoluble extracellular polysaccharides

Intra cellular polysaccharides

ibms: lipids and carbs (5 decks)

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