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Endo I > Microbiology of the RC System > Flashcards

Microbiology of the RC System Flashcards

1
Q

describe the RCS

A

warm, moist and nutritious - lots of substrate - and has a variable but largely anaerobic climate

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2
Q

why is the RCS protected from the host defenses

A

due to lack of circulation in a diseased pulp

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3
Q

what is the anaerobic glove box technique and what did it find

A

many of the pathological bacteria found in the RC system are black pigmented anaerobic G rods

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4
Q

what are the black pigmented anaerobic G rods that are found int he RCS

A
  • porphyromas sp
  • prevotella nigrescens
  • peptostreptococcus
  • fusobacterium
  • eubacterium
  • actinomyces
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5
Q

what is the most common bacteria in endo infections

A

prevotella nigrescens

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6
Q

what do black pigmented anaerobic G rods release

A

lipopolysaccharides (LPS) AKA endotoxins

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7
Q

what do endotoxins cause

A

fever, collagenolysis, osteolysis

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8
Q

the canal walls/spaces are conducive to the formation of ____

A

biofilm

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9
Q

what are biofilms

A

complex, colonized communities of bacteria

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10
Q

what does biofilm adhere to

A

the root canal walls

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11
Q

what are the floating bacteria in the root canal system called

A

planktonic

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12
Q

which bacteria come out during root canal

A

planktonic and biofilm bacteria

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13
Q

how do we clean the isthmus

A

irrigating

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14
Q

what is the profression of RCS infections

A
  • carious lesion or trauma opens tubules to bacterial invasion
  • bacteria inflame pulp locally
  • inflammation may overcome pulpal defenses and localized abscesses may form in coronal pulp
  • infection increases in pulp and necrosis begins
  • necrosis involves entire RCS
  • infection uses portals of exit (apical foramen and lateral canals) to invade peri- radicular tissues (apical periodontitits)
  • periradicular infection occurs beyond apex (apical abscess)
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15
Q

what 6 things must biofilm accomplish to cause disease within RCS

A
  • MO must adhere to host surfaces
  • obtain nutrients from the host
  • multiply
  • invade tissue
  • overcome host defenses
  • induce tissue damage
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16
Q

what is the definition of a biofilm

A

multicellular microbial community characterized by cells that are firmly attached to a surface and enmeshed in a self produced matrix of extra cellular polymeric substance (EPS) usually polysaccharide

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17
Q

what is the most common anaerobic gram - microorganisms in primary endodontic infections

A

porphyromonas
- prevotella
- peptostreptococcus
- streptococcus
-actinomyces
- olsnella
- propionibacterium

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18
Q

the longer the infectino exists within the RCS the more _____

A

oxygen is consumeed by bacterial activity and the more anaerobic becomes the RCS environment

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19
Q

chronic infections within the RCS tend to favor _______ bacterial flora

A

anaerobic

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20
Q

______ is responsible for an endo infection

A

NO one organism

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21
Q

all endo infections are _____

A

mixed or polymicrobial

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22
Q

what bacteria are endo infections

A

mostly facultative and obligate anaerobes

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23
Q

what environments can facultative anaerobes live in

A

aerobes which can survive in anaerobic environment

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24
Q

how can facultative anaerobes become more numerous and virulent

A

with addition of oxygen

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25
Q

would it benefit obligate anaerobes to add oxygen

A

no NaOCl liberates O2

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26
Q

when does biofilm become more varied, complex and difficult to control

A

when the tooth is further challenged by salivary contact or operative contamination

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27
Q

how do you avoid biofilm becoming more varied

A
  • avoid leakage of rubber dam or temporary
  • avoid iatrogenic contamination during treatment
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28
Q

how do we destroy bacteria

A

bleach or NaOCl or 8.3% sodium hypochlorite

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29
Q

what is necessary for bleach to act on bugs

A
  • bugs must adhere to host surfaces
  • obtain nutrients from the host
  • multiply
  • invade tissue
    -overcome host defenses
  • induce tissue damage
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30
Q

what does bleach do

A
  • disinfects over time
  • dilutes and inactivates toxins
  • dissolves substrate over time
  • dissolves necrotic tissue over time
  • flushes and floats out debris
  • lubricates canal
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31
Q

what are diverse shapes resistant to

A

mechanical shaping: files never reach all spaces in the complex pulpal system

32
Q

what amount of NaOCl is typically required

A

10-12 cc

33
Q

how often must NaOCl be replenished and why

A

3-5 minutes because it degrades rapidly to NaCl in the canal

34
Q

what is the 30/30 rule

A

NaOCl must be in contact with shaped canal a minimum of 30 minutes after canal enlarged to #30 or larger

35
Q

what will happen to a canal smaller than #30

A

it will seldom ever allow any irrigant to reach the apical third of the canal

36
Q

what do intracanal medications do

A

medications placed within the canal system between appointments
- intended to increase local anti microbial action and to further decrease the microbial challenge within the RC system - decreases amount of microbes

37
Q

what intracanal medications are not acceptable

A

CMCP, Formocresol, cresatin, beachwood creosote

38
Q

what is the intracanal medicatino of choice

A

CaOH

39
Q

what is the pH of CaOH

A

between 11-12

40
Q

what are the properties of CaOH

A
  • discourages most microbial growth
  • long lasting
  • no reported allergies
  • easy to apply to remove as a paste
41
Q

what is the intracanal medication CaOH called in clinic

A

Ultracal

42
Q

the use of antibiotics to relieve pain in endo is ______

A

useless

43
Q

when are systemic antibiotics useful

A

only in acute P-R infections (swelling and fever) or for a patient who is immuno supressed

44
Q

what symptoms do not require antibiotics

A

symptomatic pulpitis, symptomatic apical periodontitis, a draining sinus tract, or localized swelling

45
Q

what temperature qualifies as a fever

A

100.3 F

46
Q

drainage is accomplished by____

A

Incision and drainage

47
Q

do you give antibiotics with incision and drainage

A

yes

48
Q

use antibiotics in conjunction with definitive procedures to debride and drain where there is:

A

persistent or spreading infection
- systemic involvement with temperature over 100 deegrees
- medically compromised patient
- pre med when indicated

49
Q

what happens if the bacteria from the infected pulp gainentry into the periradicular tissue and the immune system

A

acute periradicular abscess, cellulitis or both
- patient experiences swelling, fever, and mild to severe pain

50
Q

depending on the relationship of the apices of the involves tooth to the muscular attachments, virulence factros and host resistance the swelling may be _______

A

localized to the vestibule or may extend into a fascial space (cellulitis)

51
Q

what systemic manifestations with cellulitis patients have

A

fever chills and lymphadenopathy headache and nauses

52
Q

what qualifies as a serious critical infection of the fascial plane

A
  • the involved tooth may not show radiographic evidence of a widened PDL space, most cases the tooth elicits a positive response to percussion and the periradicular area is tender to palpation
53
Q

is lesion exits coronal to muscle attachment it is generally on ______

A

attached gingiva or alveolar mucosa and we have a localized abscess

54
Q

what are fascial spaces

A

potential anatomic areas that exist between the fascia and underlying organs and other tissues. during an infection these spaces are formed as a result of the spread of purulent exudate

55
Q

what is the spread of infections of odontogenic origin into the fascial spaces of the head and neck determined by

A

the location of the root end of the involved tooth in relation to its overlying buccal or lingual cortical plate and the relationship of the eapex to the attachment of a muscle

56
Q

critical infections have the potential to be ____ if not treated aggressively

A

lethal

57
Q

why do we need to be cautious of 2nd and 3rd molar infections

A

they can cause cellulitis in the submandibular space and cause difficulty swallowing
- there is access from submandibular space to sublingual and submental

58
Q

what is Ludwigs angina

A

3 spaces (submental, submandibular, and lsublingual) are infected and it can be life threatening

59
Q

endodontic infections may be classified according to:

A

-location
-symptoms (acute or chronic)
- degree of virulence or organization (localized or diffuse spreading)

60
Q

what are the locations of endodontic infections

A
  • intraradicular
  • extraradicular
61
Q

what is intraradicular caused by

A

bugs colonizing within the RCS

62
Q

what is extraradicular infection usually a sequel to

A

untreated intraradicular infection

63
Q

what is extraradicular infection characterized by

A

microbial invasion of the periradicular tissues resulting in inflammation and infection. AAA or CAA

64
Q

what are the 3 subclasses of intraradicualr infections

A
  • primary infections
  • secondary infections
  • persistent infection
65
Q

what is primary infection caused by

A

caused by bugs that initially invade and colonize necrotic pulp tissue within the RCS

66
Q

what is secondary infection caused by

A

bugs not present in the primary infection but introduced into the RCS sometime following professional intervention (secondary to professional intervention; iatrogenic by definition)

67
Q

what is persistent infectino caused by

A

bugs that were members of a primary or secondary infection and in some way resisted intracanal antimicrobial procedures and were able to endure periods of nutrient deprivation within the RCT - failure of RCT to heal

68
Q

what is a virulence factor in RCS

A

the ability to form BIO
- neighboring cells of different species can produce enzymes such as B lactamase, catalase and proteinases that are retained in the biofilm matrix and can protect other bacteria against antibiotics and host defenses

69
Q

gram negative anaerobes can cause direct tissue damage and osseous breakdown by releasing:

A
  • enzymes: collagenase, chondroitinase, hyaluronidase
  • endotozins: toxic substances associated with the oter cell walls that are released upon destruction of the cell walls and exotoxins
  • LPS (in gram negative)
  • peptides/amino acids
70
Q

what is a virulent facultative anaerobe

A

staphylococcus aureus (aka) S. pyogenes (gram positive) can cause supprative infections

71
Q

what does staphylococcus produce

A

penicillinase- a beta lactamse that has the potential to render penicillin ineffective

72
Q

how do you treat staphylococcus aureus

A

Augmentin

73
Q

what is augmentin made of

A

amoxicillin and clavulanic acid

74
Q

what does clavulanic acid do

A

inhibits penicillinase

75
Q
A

Endo I (13 decks)

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