Module 6 Exam 2 Flashcards
(108 cards)
1
Q
What is a bacterium?
A
simpilest organisms and can be seen only through a microscope
2
Q
Innocuous
A
bacteria that arent harmful
3
Q
pathogenic
A
bacteria that are capable of causing disease
4
Q
What is another term for pathogenic bacteria?
A
virulent bacteria
5
Q
What are the most abuntant type of cells?
A
bacteria
6
Q
What helps bacteria to adapt rapidly to changes in their environment?
A
they can repilcate quickly
7
Q
What is the protective layer of bacteria
A
cell membrane
8
Q
What is used to classify and ID bacteria
A
cell membrane
9
Q
What color are gram positive bacteria
A
purple
10
Q
what color are gram negative bacteria
A
red
11
Q
What are characteristics of gram positive bacteria?
A
- single thick cell membrane
- associated with healthy periodontium
12
Q
what are characteristics of gram negative bacteria
A
- double cell membranes
- important role in tissue destruction in perio
13
Q
What are facultative anaerobic bacteria?
A
can exist either with or without oxygen
14
Q
What is another name for free floating bacteria?
A
planktonic bacteria
15
Q
What are the 2 bacterial lifestyles?
A
free floating or attached bacteria
16
Q
What are attached bacterial communities described as?
A
they are described as living in a biofilm
17
Q
Does an attached bacteria have a whole new set of characteristics from when it was a free floating bacteria?
A
Yes
18
Q
what percentage of all bacteria on the earth live as attached
A
99%
19
Q
Where do most bacteria live?
A
in complex communities called biofilm which are found everywhere in nature
20
Q
What is a biofilm?
A
it is a living film containing a communitiy of bacteria that grows on a surface
21
Q
Where can biofilms exist?
A
on any solid surface that is exposed to a bacteria containing fluid
22
Q
What disease was a result of a bacterial biofilm in a hotels air conditioning system?
A
Leigonnaires disease
23
Q
What percentage of diseases are estimated are biofilm induced
A
65
24
Q
What are some biofilm induced diseases
A
TB, cystic fibrosis, subacute bacterial endocarditis, perio disease
25
What are the 3 stages of a biofilm life cycle?
attachment, growth, detachment
26
What happens in the growth stage of the biofilm life cycle?
attached bacteria release substances to attract other bacteria to join the biofilm community
27
What is secreted and helps keep the bacteria attached to the surface and protect them in the growth stage of the biofilm life cycle?
extracellular slime layer
28
What does mature biofilm look like?
it is mushroom shaped
29
How does mature bacteria detach in the biofilm life cycle?
clumps break off and are carried away by the fluid surrounding the biofilm
30
What do detached clumps of biofilm do?
they can attach to other portions of a surface and form new colonies
31
How many different species and subspecies are capable of colonizing the mouth?
700
32
What kind of bacteria is presesnt in periodontally healthy sites
gram positive facultative rods and cocci
33
what percentage of gram-negative rods are found in periodontally healthy sites?
13%
34
Most of the bacteria in perio healthy sites are motile? T/F
false they are non motile
35
What do the bacteria found in chronic gingivitis consist of?
almost equal proportions of gram positive and gram negative bacteria
36
What percentage of gram negative rods are found in chronic gingivitis?
40%
37
What bacteria are associated with periodontitis?
an enormous number of gram negative bacteria
38
How many bacteria can be cultured from an individual tooth surface in periodontitis?
100,000 to 100,000,000 bacteria
39
What percentage of gram negative rods comprise the bacteria in periodontitis?
74%
40
Chronic periodontitis is associated with what?
high proportions of gram negative and motile bacteria
41
Is the bacterial composition of perio the same in every patient and on every tooth?
no
42
What are the 3 designated periodontal pathogens?
- A.actinomycetemocomitans
- P. gingivalis
- t. forsythia
43
What is aggregatibacter actinomycetemcomitans strongly assoicated with?
aggresive periodontitis
44
What is aggregatibacter actinomycetmcomitans capable of?
evading normal host immune response and of destroying gingival connective tissue and bone
45
What is the role of t. forsythia?
it distinguishes subjects with periodontitis from those who are periodontally healthy
46
What is the most common species detected on or in the epithelial cells recovered from perio pockets?
T. forsythia
47
The risk of perio attachment loss is higher in adolescents who are colonized by ______ than in those who do not have it
T. forsythia
48
Where is p.gingivalis found?
in low numbers in health or gingivits but is more frequently detected in aggressive forms of periodontitis
49
What species is found in increased numbers in subjects exhibiting periodontal disease progression?
p. gingivalis
50
what bacteria is commonly seen in sites that have exhibited recurrence of disease or persistence of deep pockets?
porphyromonas gingivalis
51
what can inhibit migration of leukocytes across an epithelial barrier?
porphyromonas gingivalis
52
Is periodontal disease caused by one bacteria?
no they are caused by multiple bacteria/mixed infections
53
Are periodontal diseased communicable ?**
no there is little or no evidence
54
What are the five phases of dental plaque biofilm development?
1-formation of pellicle
2-attachment of early bacterial colonizers
3-coaggregation of additional bacterial colonizers
4-formation of an extracellular slime layer
5-mature biofilm
55
What do mature biofilm have?
bacterial microcolonies that form complex groups with a primitive communication system and fluid channels
56
The aquired pellile forms within minutes, what is its purpose?
to protect the enamel from acidic activity, alters the charge and energy of the tooth surface facilitating bacterial adhesion
57
How long after pellicle formation does bacteria begin to attach?
within a few hours
58
How is the extracellular slime layer produced?
the bacteria excrete it when it attaches
59
after the tooth has been covered with the attached bacteria how does biofilm grow?
through cell division
60
What are bacterial blooms?
periods when specific species or groups grow at rapidly accelerated rates
61
what is the result of mustroom shaped colonies?
it allows complex collections of different bacteria to be linked to one another
62
Are bacteria in biofilm distributed evenly?
no
63
What does the extracellular slime layer do?
protects the bacterial microcolonies from antibiotics, antimicrobials, and the bodys immune system
64
What influences the shape of the biofilm as well as the spatial arrangement?
fluid forces
65
What happens when the biofilm extensions break free?
they can be swallowed, expectorated, or form new colonies in the mouth
66
fluid forces also cause cell to cell collisions of the bacteria in the biofilm which and lead to what?
more rapid spread of genes among the bacteria than normal
67
why is the bacterial biofilm very difficult to irradicate?
because of the continuous exchange of genetic information means the bacteria are continually evolving
68
What do fluid channels do?
bring in nutrients and oxygen to the bacteria as well as carry waste away
69
How do cells communicate with eachother?
by chemical signals
70
How does biofilm develop?
by stacking one bacterial species on top of another
71
what is coaggregation?
cell to cell adherence of one oral bacterium to another, is random
72
the first bacteria to colonize the tooth are non pathogenic t/f
true
73
What are some example of the early non pathogenic colonizing bacteria?
streptococcal mitis or oralis, actinomyces viscosus
74
What are examples of the intermediate species of colonizers?
fusobacterium nucleatum
75
can free floating bacteria cause perio disease?
no
76
Where does the most pathogenic bacteria attach?
to the pocket epithelium
77
3 to 12 weeks after supragingival biofilm starts to form what is happening?
subgingival biofilm is mature with gram negative anaerobic bacteria
78
what are the zones of subgingival bacterial attachment
tooth surface and epithelial lining of the periodontal attachment
79
What biofilm is the most detrimental to the periodontal tissues?
tissue associated plaque biofilm
80
what is the primary cause of the destruction seen in periodontitis?
the bodys immune response to plaque biofilm
81
the inflammation that causes most of the damage in periodontitis is what
a continuous low grade inflammation occuring 24 hours a day
82
is it bacteria alone that causes perio disease?
no, is is the interplay between the bacteria and the host response that results in tisse destruction
83
what is a virulence factor?
the mechanisms that enable biofilm bacteria to colonize and invade the tissues of teh periodontium
84
what makes periodontitis mroe resistant to treatment?
the presence of bacteria in the tissues
85
what are exotoxins
proteins released from the bacterial cell that act on host cells at a distance
86
what are bacterial enzymes
agents that are harmful or destructive to host cells
87
once released bacterial enzymes have the ability to
- increase permeability of epithilial lining of sulcus
- contribute to the breakdown of the collagen fibers in the gingival connective tissue
- promote apical migration of the JE
- widening of intracellular spaces
- diminish ability of immunoglobulins or other body proteins to defend the host
88
When do antimicrobial agents work best?
in conjunction with mechanical cleaning
89
Antibiotics only work on what?
bacteria that are active and reproducing, not dormant bacteria
90
control of bacteria in dental plaque biofilms is best achieved by
the physical disruption of plaque biofilm (brushing, flossing, and perio instrumentation)
91
What is the host response?
the way that the body responds to perio pathogens
92
what are biochemical mediators
immune cells that secrete biologically active compounds that activate the bodys inflammatory response
93
what are cytokines?
powerful regulatory proteins released by the immune cells that influnce the behavior of other cells
94
waht are some functions of cytokines?
- recruit cells to infection site
- increase vascular permeability
- have the potiential to initate tissue destruction and bone loss in chronic inflammatory diseases
95
what is a prostaglandin?
series of powerful biochemical mediator of which D, E, F, G, H, and I are the most important
96
Which prostaglandin plays an important role in the bone destruction seen in perio?
prostaglandins of the E series
97
What are 2 important sources of prostaglandins?
macrophages and PMNs
98
What are functions of prostaglandins?
- increase permeablity and dilation of blood vessels
- trigger osteoclasts
- promote overproduction of MMP enzymes
99
what is the biggest thing to know about prostaglandins?
initiatie most of the alveolar bone destruction in periodontitis
100
What is MMP?
Matrix mealloproteinases are 12 different enzymes that break down teh connetive tissue matrix
101
What are the major sources of MMP perio disease?
PMN and gingival fibroblasts
102
What are the functions of MMPs
- in health factilitate normal turnover of perio connetive tissue matrix
- in infection, released to kill invading bacteria
- overproduction breaks down connective tissue of periodontiium
103
What is one of the most important things to know about MMPs
in the presence of increased MMP levels extensive collagen destruction occurs in the perio tissues
104
What are the distinct stages in histologic development of gingivits and periodontitis?
- early plaque biofilm accumulation
- early gingivitis
- established gingivits
- periodontitis
105
What are the steps in early bacterial accumulation phase in inflammatory perio disease?
- initial bacterial colonization
- initiation of host response
- activation of complement system
- outcome of host response
106
In early gingivits:plaque biofilm overgrowth phase in inflammatory periodontal disease
- pathogens invade connective tissue
- migration and chemotaxis of PMN
- Migration of additional cellular defenders
- outcome of host response
107
In established gingivits: subgingival plaque biofilm phase in inflammatory perio disease what are the steps?
- establishment of subgingival plaque biofilm
- migration of additional celluar defenders to site
- outcome of host response
108
what are the steps in periodontitis: tissue destruction phase?
- bacterial pathogens flourish in biofilm
- host response intensifies
- destruction of perio tissues ensues
- outcome of host response
