Week 8 Rodrigo- Endodontic Microbiology Flashcards
What can lead to endo infections?
- Caries
- Trauma
- Perio disease
- Invasive operative procedures
Where are the dentinal tubules the largest vs smallest diameter?
- Largest diameter near the pulp (2.5um)
- Smallest diameter near enamel/cementum (0.9um)
What is the major cause of pathogenesis of endodontic infection?
Bacteria
How can periodontal pathogens reach pulp?
- Dentinal tubules
- Apical and lateral ramifications
What are the microbiological goals of endo treatment?
Eradicate bacterial colonisation or reduce bacterial load to levels that permit periradicular tissue healing
How much of a root canal remains untouched after root canal treatment? + consequence of this?
60-80%. Instruments usually fail to touch all the walls causing unprepared areas to harbour microorganisms
What is required for disease and signs/symptoms to come about?
- 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
What factors contribute to pathogenesis? What can we influence as denstist?
- Numbers of bacteria
- Virulence
- Interaction
- Resistance
P=NVI/R
We can reduce number of bacteria as dentists
What bacteria are associated with failed RCT?
- Gram +ve are more resistant to root canal treatment e.g. E- faecalis
- Gram -ve are easier to kill
What causes pulpal inflammation before pulp is exposed?
Diffusion of bacterial products through dentinal tubules
Where are bacteria in apical periodontitis vs abscess?
- 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)
What are biofilms composed of?
- Bacteria (15%)
- EPS matrix- polysaccharides, proteins, nucleic acids (85%)
What is intra-radicular infection + 3 types?
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
What is secondary infection caused by?
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
What is primary infection caused by?
Caused by microorganisms that initially invade and colonise necrotic pulp tissue