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Perio 1 > Bio/Etiology of Perio Diseases > Flashcards

Bio/Etiology of Perio Diseases Flashcards

1
Q

How were early oral microbials first discovered?

A

cultivation and microscopy; What we can grow, we know

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2
Q

Describe the great plate anomaly.

A

Organisms you see in the mouth do not all grow on an agar plate

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3
Q

What microbiology technique allowed us to learn about more microbes in the oral cavity?

A

16S gene PCR tests

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4
Q

How many species can inhabit the oral cavity?

A

700+

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5
Q

How many species inhabit the oral cavity of one individual?

A

40 - 120 species; each person has a unique microbial fingerprint

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6
Q

Is the oral microbiome made up of only bacteria?

A

No, fungi, parasites, and viruses also inhabit the oral cavity.

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7
Q

Describe the oral cavity of a human fetus.

A

sterile

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8
Q

How long after birth does a baby develop its first oral microbes?

A

4 minutes after birth the first bacteria begin to colonize the oral cavity; likely from the maternal vagina/rectum

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9
Q

At what age is a child’s human microbiome first similar to an adult’s human microbiome?

A

age 2; over 400+ microbes in the human body; most of the oral microbiome is established by the first week of life

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10
Q

Whose oral microbiome is a child’s oral microbiome most similar?

A

the child’s mother

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11
Q

What is one important characteristic of bacteria needed to survive in the mouth?

A

adhesions

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12
Q

What are the 5 major niches of the oral cavity?

A

supragingival; tonsils, dorsum of tongue; buccal, FOM, and palatal epithelium; periodontal/periimplant pocket

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13
Q

Do all species colonized on all niches of the mouth?

A

No, spirochetes do not

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14
Q

_____ of bacteria to oral epithelial cells is directly related to its virulence.

A

Adherence

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15
Q

Are teeth and dental implants microbially the same? Why?

A

No; the tooth has a junctional epithelium that protects the periodontum from microbial species. Implants do not have this.

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16
Q

Should you place an implant if a patient has active periodontal disease? Why?

A

No, because the bacteria from teeth can transfer to the implant and result in failure.

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17
Q

What structure is the primary habitat for periodontopathogens?

A

teeth

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18
Q

Describe dental plaque.

A

microbes entangled in an ECM that colonize on teeth, soft tissues, restorations in the mouth; have specific inter-bacterial and host-bacterial interactions

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19
Q

Is the number of bacteria in the mouth the same as the number of bacteria in the gut?

A

yes

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20
Q

If you floss and brush the recommended daily amount, what percent of plaque do you remove?

A

40%

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21
Q

What is special about the oral microbiome and the immune system at a young age?

A

they co-evolve

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22
Q

What are the 5 stages of biofilm formation?

A 
association
adhesion
proliferation
microcolonies
biofilm formation
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23
Q

Within how many minutes of a prophy does a pellicle form?

A

2 minutes

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24
Q

Term used for the first bacteria to colonize a tooth surface.

A

primary colonizer

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25
Q

What are a few examples of common primary colonizers?

A

Streptococcus
Neisseria
Actinomyces
Veillonella

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26
Q

What is a common secondary colonizer/bridge species in the oral cavity?

A

Fusobacterium nucleatum

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27
Q

If you had an oral cavity more susceptible to pathogenic bacteria, what bacterium would be a contributing factor to that?

A

Fusobacterium nucleatum:

more F. nucleatum in the mouth = more opportunity for pathogenic bacteria to stick

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28
Q

What are 3 important ways bacteria benefit the human body systemically?

A
  1. bacteria in the oral cavity keep pathogens at a low
  2. bacteria educate our immune system
  3. bacteria break down dietary nitrates
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29
Q

Why is nitrate breakdown via bacteria important?

A

The break down product is nitrous oxide, which is a vasodilator. This decreases blood pressure

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30
Q

Term for bacteria that adhere to pellicle.

A

Planktonic bacteria

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31
Q

To what structure in saliva do primary colonizers adhere?

A

salivary glycoproteins

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32
Q

How do bacteria differ in attachment ability?

A 
rapid attachers (specific mechanism/structure)
slow attachers (nonspecific)
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33
Q

What happens to bacterial characteristics after attachment to a pellicle?

A

The bacterial phenotype changes:
like outer membrane proteins.
AND the bacteria grow

34
Q

Define co-aggregation.

A

2 different species connecting through specific mechanisms
typically glycoprotein receptors on one cell connect to carbohydrates on the other cell.
both cell types are in suspension

35
Q

Define co-adhesion.

A

interactions between suspended and already adhering micro-organisms. (bridging microbes)

36
Q

What influences co-adhesion?

A 
Temperature (high temps = no co-adhesion)
and lactose (increased levels = decrease in co-adhesion)
37
Q

What two processes occur in biofilm growth?

A

co-aggregation

co-adhesion

38
Q

What occurs during the maturation of a biofilm?

A

increase in diversity
replication and matrix formation
ecological succession

39
Q

What is an example of a tertiary colonizer?

A

Porphyromonas gingivalis

40
Q

Why are pathogens considered pathogens?

A

because they produce virulence factors that our immune system does not like, triggering an immune response

41
Q

If the biofilm changes and becomes thicker, what happens?

A
  • difficulty in diffusion in and out of biofilm (bacteria get trapped and die b/c low oxygen)
  • oxygen gradient develops (goes from aerobic to anaerobic)
  • reverse gradients of fermentation products develop as result of bacterial metabolism
42
Q

Where does supragingival plaque/bacteria gain nutrients from?

A

nutrients dissolved in saliva

43
Q

Where does subgingival plaque/bacteria gain nutrients from?

A

gingival crevicular fluid (GCF) and blood

44
Q

What happens do the oral microbiome if subgingival plaque/bacteria gain their nutrients from blood?

A

the oral ecosystem will shift

45
Q

What 2 products do bacteria break macro-molecules into?

A

peptides and amino acids

46
Q

What is a special characteristic of chlorohexidine?

A

It has substantivity - it can stay and be released over a period of time. It is also an anionic agent.

47
Q

What makes up a biofilm?

A

microcolonies and interbacterial matrix

48
Q

What are 3 sources for the intercellular/interbacterial matrix?

A

dead bacterial cells
saliva
gingival exudate

49
Q

Are there voids/water channels within the matrix of a biofilm? Why?

A

yes, that is a way one part of the biofilm communicates with another part.

50
Q

What is the backbone of a biofilm?

A

exopolysaccharides

51
Q

What comprises the lower layer of the biofilm?

A

dense layer of microbes
polysaccharide matrix
tightly bound
steep diffusion gradients

52
Q

What comprises the loose layer of the biofilm?

A

irregular appearance

extends into surrounding medi

53
Q

What comprises the fluid layer of a biofilm?

A

stationary sublayer
fluid layer in motion
nourishes the biofilm by molecular diffusion

54
Q

What is the structure of supragingival plaque?

A

The shape of the microcolonies depends on the force around them, and the interbacterial matrix is highly variable. Supragingival plaque is a high friction area (tooth surface, gingiva)

55
Q

Which microcolony has a low shear force?

A

towers or mushrooms

56
Q

Which shape microcolony has a high shear force?

A

elongated colonies capable of oscillation

57
Q

Describe the interbacterial matrix if gram positive bacteria are mostly present.

A

The matrix is very fibrillar due to dextrans and levans

58
Q

Describe the interbacterial matrix in a biofilm if gram negative bacteria are mostly present.

A

very regular with trilaminar vesicles

filled with endotoxins and proteolytic enzymes; involved in adherence

59
Q

Why are interbacterial carbohydrates important?

A

They provide an energy source (dextrans, fructans) and are the skeleton of plaque (mutans).

60
Q

Describe the structure of subgingival plaque.

A

similar to supragingival plaque but layers near the sulcular epithelium have no interbacterial matrix and contain more spirochetes and flagellated bacteria

61
Q

What factors affect plaque formation?

A 
Diet/food
smoking
copper amalgam
tongue and palate brushing
mandible compared to maxilla
etc.
62
Q

Why do bacteria in a biofilm collaborate?

A

it is necessary for succession

63
Q

Streptococcus cristatus is a primary colonizer and can live with or without oxygen. In the presence of oxygen it is an _____ _____. When it uses oxygen it creates tiny anaerobic pockets that creates an environment for anaerobic microbes

A

oxygen scavenger

64
Q

What are some advantages of biofilm living?

A

defense
protection from external changes (shearing forces, antiobiotics)
transfer of information and genetic material
metabolic cooperation

65
Q

How does the biofilm protect microbes?

A
  • allows bacteria to go unnoticed

* allows bacteria to avoid immunoresponse

66
Q

Define quorum sensing.

A

regulation in gene expression in response to accumulation of signaling compounds that mediate intercellular communication. i.e. when signaling molecules reach threshold concentration, they begin to have an effect so other bacteria express virulence

67
Q

What microbe is known to participate in quorum sensing?

A

Porphyromonas gingivalis - it is a community activist

68
Q

What are some benefits of quorum sensing?

A

antibiotic resistance in dense biofilms
encourages growth of beneficial species
commensal bacteria produce and respond to low levels of AI-2
Pathogens produce AI-2 in high levels

69
Q

What might determine a switch from a commensal to pathogenic community?

A

autoinducer (AI) 2

70
Q

What is a bactericidal antibiotic?

A

one that targets the cell wall

71
Q

What is a bacteriostatic antibiotic?

A

interfere with protein synthesis

72
Q

How many more times are biofilm bacteria resistant to antibiotics than planktonic bacteria?

A

1000-1500 times

73
Q

Do biofilm bacteria grow fast or slow?

A

They grow slow

74
Q

How does bacterial growth affect antibiotics?

A

If the bacteria are not growing, the antibiotics are not going to work

75
Q

Do slow or fast growers express more exo-polymers?

A

slow growers

76
Q

What is an exo-polymer?

A

biopolymer secreted by an organism: like a biofilm

77
Q

What are some mechanisms of antibiotic of resistance?

A

slow growing bacteria
exopolymers retard diffusion
biofilm bacteria express different genes (phenotypic change)

78
Q

How do exopolymers prevent antibiotic penetration?

A 
ion-exchange mechanisms prevent highly charged molecules from reaching deeper zones
extracellular enzymes (beta-lactamase) inactivate antibiotics
79
Q

What exopolymer secretions inactivate antibiotics?

A

beta lactamase
formaldehyde dehydrogenase
formaldehyde lyase

80
Q

Why are biofilms clinically significant?

A

antibiotic resistance

can be targets for therapy (vaccines)

81
Q

Biofilms/bacteria can ____ pathogens from pockets to healthy sites in the mouth.

A

translocate

82
Q

What is the rationale for one-stage, full-mouth disinfection by Leuven?

A

translocation of bacteria

Perio 1 (2 decks)

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