9 - Endodontic Microbiology Flashcards
role of bacteria in endo
- Bacteria required for pulp disease
- Pulp damage required for infection
- Bacteria usually confined in canal
what is the main source of bacterial contamination of pulp tissue
caries
how many dentinal tubules per sq. mm of dentin
15,000
diameter of dentinal tubule
1 to 4 microns
most bacteria is ___micron
less than 1 micron
who was the first person/year to first associate bacteria with pulpal disease
W.D. Miller 1890
who proved and year than bacteria are the cause of pulpal and PA disease
Kakehashi 1965
T/F: pulp status is very important in its susceptibility to colonization
TRUE
because of lack of circulation, what is absent in necrotic pulp
normal host defense
what causes an apical lesion
toxins and bacteria
what is done to eliminate infection from canal
endo therapy
is the body defense capable of taking care of apical lesion
yes
routes of bacterial contamination
- Open Cavity
- Dentinal Tubules
- Periodontal disease
- Developmental defects
- Infection from another tooth?
what are examples of developmental defects
is there one specific bacteria in endo infections
no
are endo infections native to oral cavity
yes
endo infections are [single OR mixed] infections
MIXED
what bacteria are in caries (ea. layer)
- S. Mutans on superficial layers
- Anaerobes in deepest layers
- Actinomyces in root caries
T/F: Following pulp exposure numerous species of opportunistic bacteria can invade and colonize the pulp
TRUE
what are bacteria in polymicrobial infections
- Strict anaerobic bacteria
- Facultative anaerobes
- Rarely aerobes
The predominance of ___ suggests that a selective process favoring the growth of these bacteria takes place. In time, the proportion as well as the total number of ___ increases
strict anaerobes; strict anaerobes
what is the ecological environement of root canal
- Rich substrate of nutrients (polypetides and aminoacids)
- Low oxygen tension
- Bacterial interactions
T/F: the growth of some bacterial species INDEPENDENT on the metabolic byproducts of other species
FALSE! DEPENDENT!
what is bacteria organized in complex microbial community
biofilm
what is composed of great variety of bacteria with different ecological requirements and pathogenic potential
biofilm
what protects microorganisms from host immunological resistance
biofilm
what protects microorganisms from therapeutic measures such as medicaments and irrigating solutions
biofilm
can the same patient have different combination of bacteria on one tooth compared to another tooth in the same oral cavity
YES
is black pigmented bacteria (BPB) anaerobic or aerobic
anaerobic
BPB previously know as what
black pigmented bacteria (BPB) previously known as bacteriodes
anaerobic organisms are currently classified in what genus
prevotella and porphyromonas
what is the accurate way of detecting and classifying microorganisms to find DNA or RNA
PCR
what can invade periapical lesion and cause a rare persistent infection that will not heal after endodontic therapy
actinomyces isralii
Associated with failing root canals
Can persists after root canal treatment
Resistant to some medications
Difficult to erradicate
enterococcous faecalis
Associated with painful symptoms during root canal infections
Involved with other microorganisms in mixed infections
prevotella melaninogenica
___ is the most common BPB cultivated from endodontic infections
Porphyromonas Nigrescens
what is responsible for dentin staining during endo infections
Porphyromonas Nigrescens or just an endo bacteria
Periapical healing occurred in 94% of cases with [positive or negative] cultures at time of obturation
negative
Only 68% healing in cases that had [positive or negative]
cultures at time of obturation
positive
what are other organisms found in the pulp
- Viruses (HIV)
- Yeasts (Candida Albicans)
- Spirochetes
7% of 692 samples of therapy resistant chronic apical periodontitis showed the presence of what
fungi/candida albicans
tests to detect bacteria
- sensitivity test
- gram stain
- special cultures needed for anaerobic bacteria
- PCR testing
what test to determine which antibiotics would be most affective against bacteria
sensitivity
what test to determine bacteria type
gram stain
when to culture
- Tooth does not respond to treatment
- Persistent symptoms
- Sinus tract will not heal
- Persistent exudate in canal
what is the aseptic technique
- Field of operation
- Sterilized instruments and materials
- Disinfected surfaces in operatory
- Operator barrier protection (gloves, mask, PROTECTIVE GLASSES etc.)
- Canal disinfection
- Coronal seal
endo infection will persist until when
until source is removed
what is done in endodontic therapy against bacteria
- Chemo-mechanical debridement
- Use of antimicrobials
- Canal obturation
- Coronal restoration
are antibiotics effective in endo? why?
Because of a lack of blood supply antibiotics are not effective in destroying the reservoir of bacteria located in the root canal
can antibiotics be used as a substitute for tx in endo
no
can a majority of endo infections be treated without the use of antibiotics
yes
can you use prophylactic antibiotics to prevent flare-ups in endo
no - not justified
what bacteria can be found in root caries
actinomyces
what bacteria can be found in caries
strep mutans
what bacteria found in periodontitis
porphyromonas
can viruses be found in the pulp space?
YES! HIV and Hep B
what bacteria is found in failing root canals and is resistant to most root canal medications
enterococcus faecalis
T/F: there is a specific bacteria that causes endodontic infections
FALSE! many different bacteria!
T/F: endodontic infections are mostly polymicrobial
TRUE (polymicrobial = multiple bacterias)
T/F: bacteria can gain access into the pulp thru dentinal tubules
TRUE
T/F: Infections in the root canal can be self sustaining due to metabolic products that are excreted by one type of bacteria and utilized as nutrients by other species of bacteria
TRUE
T/F: a carious exposure is needed for bacteria to access the pulp
FALSE! must enter via tubules
T/F: The principal etiology for pulpal disease is microbial
TRUE! (specifically polymicrobial)
T/F: bacteria in endodontic infections are mostly aerobic
FALSE! anaerobic!
