Week 8 Rodrigo- Endodontic Microbiology Flashcards

1
Q

What can lead to endo infections?

A
  • Caries
  • Trauma
  • Perio disease
  • Invasive operative procedures
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2
Q

Where are the dentinal tubules the largest vs smallest diameter?

A
  • Largest diameter near the pulp (2.5um)
  • Smallest diameter near enamel/cementum (0.9um)
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3
Q

What is the major cause of pathogenesis of endodontic infection?

A

Bacteria

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4
Q

How can periodontal pathogens reach pulp?

A
  • Dentinal tubules
  • Apical and lateral ramifications
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5
Q

What are the microbiological goals of endo treatment?

A

Eradicate bacterial colonisation or reduce bacterial load to levels that permit periradicular tissue healing

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6
Q

How much of a root canal remains untouched after root canal treatment? + consequence of this?

A

60-80%. Instruments usually fail to touch all the walls causing unprepared areas to harbour microorganisms

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7
Q

What is required for disease and signs/symptoms to come about?

A
  • Bacteria have to reach quorum of cells (threshold) to cause disease (apical periodontitis) and clinical signs and symptoms.
  • Disease will persist if canals aren’t cleaned/shaped adequately as bacterial levels are above threshold
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8
Q

What factors contribute to pathogenesis? What can we influence as denstist?

A
  • Numbers of bacteria
  • Virulence
  • Interaction
  • Resistance

P=NVI/R

We can reduce number of bacteria as dentists

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9
Q

What bacteria are associated with failed RCT?

A
  • Gram +ve are more resistant to root canal treatment e.g. E- faecalis
  • Gram -ve are easier to kill
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10
Q

What causes pulpal inflammation before pulp is exposed?

A

Diffusion of bacterial products through dentinal tubules

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11
Q

Where are bacteria in apical periodontitis vs abscess?

A
  • Bacteria are in the canal in apical periodontitis and barrier prevents spread of infection to alveolar bone (intraradicular infection)
  • Bacteria extrude through apex in abscess (extraradicular infection)
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12
Q

What are biofilms composed of?

A
  • Bacteria (15%)
  • EPS matrix- polysaccharides, proteins, nucleic acids (85%)
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13
Q

What is intra-radicular infection + 3 types?

A

Caused by microorganisms colonizing the root canal system and can be subdivided into 3 categories according to the time microorganisms entered the root canal system:

  • Primary infection
  • Secondary infection
  • Persistent infection
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14
Q

What is secondary infection caused by?

A

Caused by microorganisms not present in primary infection but introduced in root canals at some time after intervention e.g. touching GP cones or files

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15
Q

What is primary infection caused by?

A

Caused by microorganisms that initially invade and colonise necrotic pulp tissue

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16
Q

What is persistent infection caused by?

A

It is caused by microorganisms that were members of primary or secondary infection and in some way resisted intracanal antimicrobial procedures and were able to endure periods of nutrient deprivation in treated canals e.g.

17
Q

What bacteria are present in primary intraradiucalr infection?

A

Mixed (multispecies ) community dominated by anaerobic bacteria belonging to diverse genera of gram negative and gram positive bacteria. Larger lesions → high bacterial diversity and density in canal

18
Q

What are major causes of post tx apical periodontitis?

A

Persistent or secondary intraradicular infections

19
Q
A
20
Q

What disease are dependent on intraradicular infection?

A
  • Acute apical abscess
  • Chronic abscess
  • Wet canals (persistent exudation)
21
Q

What does it mean to be independent of intraradicular infection?

A

No longer fostered by intraradicular infection

Can persist even after successful eradication of intradicular infection