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**