lecture 3 Flashcards
the root canal system provides an ideal environment for
bacterial colonization
the RCS is warm, moist, and nutritious (has lots of substrate) and has a variable but largely
anaerobic climate
the RCS is now largely protected from the host defenses due to
lack of circulation in a diseased pulp
aka privileged sanctuary
unprepared root canal surface areas causes
clinical implications, and therapeutic strategies
what are the possible routes of root canal infection
- cracks or fractures
- CEJ defect
- open dental tubules
- dental caries #1 CAUSE
- lateral canal
- periodontal or periapical invasion
endodontic infections may be classified according to
location
symptoms(acute or chronic)
degree of virulence or organization (localized, or diffuse and spreading)
location:
- intraradicular (pulpal necrosis)
- extraradicular (periapical tissue)
symptoms:
acute or chronic
degree of virulence
localized or diffused
3 types of intra-radicular infections
- primary infections
- secondary infection
- persistent infection
this infection is caused by microorganisms that initially invade and colonize necrotic pulp tissue within the RCS
primary infections (type of intra-radicular infection)
this infection is characterized by a mix of 10 to 30 bacterial species dominated by ANAEROBIC BACTERIA
primary infection (type of intra-radicular infection)
this infection by microorganisms not present in the primary infection, but introduced into the RCS sometime following professional intervention
secondary infection (type of intra-radicular infection)
this type of infection is caused by bacteria that were involved with a primary or secondary infection and in some way, resisted intracanal antimicrobial procedures and were able to endure periods of nutrient deprivation within the RCS (FAILURE OF RCT TO HEAL)
persistent infection
(type of intra-radicular infection)
characterized by microbial invasion of and proliferation in the inflamed peri radicular tissue
extra-radicular infections
list the 7 steps of progression of RC system infections
- carious lesion or trauma opens tubules to bacterial invasion
- bacteria inflame pulp locally
3 inflammation may overcome pulpal defenses and localized abscesses may form in coronal pulp - infection increases in pulp and necrosis begins
- necrosis involves entire RC system
- infection uses “portal of exit” (apical foramen and lateral canals) to invade peri-radicular tissues (apical periodontitis)
- peri-radicular infection occurs beyond apex (apical abscess)
different types of molecular biology techniques have revealed the ________ of endodontic infections with a dominance of obligate _____ ______(primary infections)
polymicrobial nature
anaerobic bacteria
gram negative -
current evidence reveals that gram _____ bacteria appears to be the most common microorganisms in endodontic infections
gram negative bacteria
the longer the infection exists within the RC system, the more:
and the more:
oxygen is consumed by bacterial activity and the more anaerobic becomes the RC system environment
chronic infections within the RC system tend to favor
anaerobic bacterial flora
aerobes which can also survive in an anaerobic environment may become more numerous and virulent with addition of oxygen
facultative anaerobes
must have anaerobic environment to survive and cannot survive in an aerobic environment
obligate anaerobes
(die in presence of oxygen)
NaOCl liberates O2**
what are the main sources of nutrients for bacteria
- pulp necrosis
- saliva
- toxins
- proteins and glycoproteins
the primary cause of endodontic treatment failure has been attributed to _________usually in the form of
intra-radicular infections
form of biofilms
microorganisms present in the apical portion of the root (apical deltas and laterals canals) have the potential to substain
in a long standing infection
multicellular micorbial community characterized by cells that are firmly attached to a surface and enmeshed in a self produced matrix of extracellular polymmeric substance EPS
biofilm
the canal walls/spaces are conducive to formation of _____. once introduced, microorganisms thrive there
biofilm
(adhered to the root canal walls)
floating bacteria
planktonic
T/F
no single microorganism is responsible for endo infection
True
that means all endo infections are mixed
the microorganisms for endo treatments are mostly
facultative and obligate anaerobes
biofilms must accomplish 6 things to cause disease with the RC system
- MO must adhere to host surfaces
- obtain nutrients from host
- multiply
- invade tissue
- overcome host defenses
- induce tissue damage
Biofilm becomes more varied, complex and difficult to control when the tooth is further challenged by
salivary contact or operative contamination (new MO or altered environment)
avoid what during treatment
leakage of rubber dam or temporary
and
iatrogenic contamination
how do we destroy MO
8.3% sodium hypochlorate (NaOCl)
our major weapon cleaning and shaping with NaOCl and intra-canal medicaments
what are 6 functions of NaOCl in root canal systems
- disinfects over time
- dilutes and inactivates toxins
- dissolves substrate over time
- dissolves necrotic tissue overtime
- flushes and floats out debris
- lubricate canal
if bacteria from the infected pulp tissue gain entry into the peri-radicular tissue and the immune system is unable to suppress the invasion, an otherwise healthy patient eventually shows signs and symptoms of an:
what is patient experiencing clinically?
depending on the relationship of the apices of the involved tooth to the muscular attachments, virulence factors and host defenses, the swelling may be __________or may extend into a _________
acute periradicular abscess, cellulitis, or both
clinically experiencing swelling, fever, and mild to severe pain
localized to the vestiuble
or extended into a fascial space (cellulitis)
muscle attachments are important in relation to where the lesion “points”. if lesion exits coronal to muscle attachment, it is generally on
and we have a:
which is more:
attached gingival or alveolar mucosa and we have LOCALIZED ABSCESS
more easily treated (no systemic involvement) aka no swelling or fever
this type of patient generally will also have systemic manifestations such as fever, chills lymphadenopathy, headache, and nausea because the reaction to the infection may occur very quickly, the involved tooth may or may not shoq radiographic evidence of a widened periodontal ligament space. however, in most cases the tooth elicits a positive response to percussion and the peri-radicular area is tender to palpation. this is a serious critcal infection in ____plane
cellulitis patient
in fasical plane
_____are 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
fascial spaces
the spread of infections of odontogenic origin into the fascial spaces of the head and neck is determined by 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 apex to the attachment of a muscle
where should be especially vigilant with infections of ______ when cellulitis occurs in the submandibular space with swallowing difficulties
mand molars (2nd and 3rd)
why 2nd and 3rd molars?
access from submandibular space to sublingual and submental spaces; all 3 are called (ludwig’s angina) and infection in these spaces can be life threatening
if apices or infection above mylohyoid muscle:
if apices or infection below mylohyoid muscle:
above: sublingual space
below: submandibular space
cellulitis (ludwigs angina) infection has pointed apical to attachment of __________ and superior to the ____muscle
mylohyoid muscle
platysma muscle
what is important in controlling cellulitis infection (ludwig)
incision and drainage
referral is indicated
in conjunction with definitive procedures and debride and drain when there is:
persistent or spreading infection
systemic involvement with temp of
100+
use of antibiotics to relieve pain:
useless
systemic antibiotics are useful only in
acute Peri-Redicular infections (swelling and fever) or for a patient who is immunologically compromised
healthy patients without systemic signs and symptoms of infection but with symptomatic pulpitis, symptomatic apical periodontitis, a draining sinus tract, or localized swelling, (do/do not) require antibiotics
DO NOT
just creating RESISTANCE
the ability to form BIO has bee regarded as
a virulence factor
neighboring cells of different species can produce enzymes such as:
that are retained in the biofilm matrix and can protect other bacteria against antibiotics and host defenses
B-lactamase, catalase, and proteinases
gram negative anaerobes can cause direct tissue damage and osseous breakdown by releasing:
-enzymes [collagenase, chondroitinase, hyaluronidase]
-endotoxins [toxic substances associated with the outer cell walls that are released upon destruction of cell walls and exotoxins]
-lipo polysaccharide [LPS an endo toxin in cell wall of G-bugs]
-peptides/amino acids
this can cause serious suppurative infections
staphylococcus aureus aka S. Pyogenes (gram+)
staphylococcus aureus aka S. Pyogenes (gram+)
this bug is thought to produce ______, a B lactamase that has the potential to render penicillin ineffective
penicillinase
Rx augmentin=
amoxicillin + Clavulanic acid (inhibits penicillinase)
