W8 - Microbiology of Endo Infections - Rodrigo Flashcards
Does dentine exposure always cause potential pulp exposure?
Only when thickness is considerably reduced and permeability is increased
How does dentinal tubule size change in the tooth
Conical conformation
largest widest diameter near pulp, smallest near the enamel
Microbiological goal of endo tx (2)
Eradicate bacterial colonization or
Reduce bacterial load to levels that permit perradicular tissue healing
What percentage of root surface area remains untouched even after instrumentation
- 6% to 79.9% untouched
* this is why irrigants are important
Pathogenesis equation
What is the only thing you can change?
P = pathogenesis
N = number of bacteria
V = virulence
I = interaction
R = resistance
You can only change the number of bacteria. Not virulence, interaction, etc
Which type of bacteria are associated with more failures of endo (not species)
Why? (3)
Gram positive
- Bc they are more resistant to antimicrobials
- Can adapt to harsh environmental conditions in medicated canals
- gram neg are easy to kill
Does pulp only become inflamed once there is exposure from caries?
No - bacterial products can move through tubules and cause pulpal inflammation before exposure
Irrev pulp
Are bacteria IN the canal or OUT of the canal in apical periodontitis?
Inside the canal → the LEO is the consequence of bac in the canal
When bac are OUT of the canal → Abscess
What is in biofilm? Percentage? (2)
15% bacterial colony
85% EPS - Extracellular Polymeric Substance
2 types of endodontic infections classified by anatomic location
Intraradicular infection (3 types)
Extraradicular infection
3 types of intraradicular infection
Primary infection
Secondary infection
Persistent infection
What causes primary infection?
Caused by microorganisms that
initially invade and colonize the
necrotic pulp tissue
type of primary intraradicular infection
What causes secondary infection?
Caused by microorganisms not present in the primary
- *infection** but introduced in the root canal at some time after
- *intervention**
- type of intraradicular infection*
- Couldve been introduced by microleakage or touching the file with gloves before treatment
What causes persistent infection
caused by microorganisms that were members of primary or secondary infection and resisted intracanal antimicrobial procedures and were able to endure periods of nutrient deprivation in treated canals.
type of intraradicular infection
leftover bacteria in canal
Synonym of persistent infection
Late failure
“can even happen 12 years later”
12 years later
Late failure / persisting infection
How does the size of the lesion affect bacteria colony?
Larger the lesion = higher bacterial diversity and density
What type of bacterial species occupy primary interradicular infection?
Mixed species but mostly anaerobic bacteria of gram negative and positive type
What is the major cause of post treatment apical periodontitis
Intraradicular infection - either persistent or secondary
- Usually of gram-positive bacteria
Examples of Intraradicular vs Extraradicular infection
Intraradicular - apical periodontitis → constitutes effective barrier against spread of infection to bone and other sites
Extraradicular - abscess → bacteria have overcome the barrier and are spreading
Where is the bacteria / infection in extraradicular infection?
Have pushed through apex
What is Rodrigo’s only solution for extraradicular infection?
Apical surgery
51:45
Ex. apical periodontitis with development of external biofilm
3 Examples of extraradicular infections that are dependent on intraradicular infections
Acute / chronic apical abscess
“wet canals” - persistent exudation
2 examples of scenarios where extraradicular infection is independent of intraradicular infection
- No longer fostered by the intraradicular infection
- Persistence of extraradicular infection even after successful eradication of intraradicular infection
