Lecture 2 (8/29) Flashcards
Provides an ideal environment for bacterial colonization:
Root canal system
Why is the RC system an ideal environment for bacterial colonization:
- Warm
- Moist
- Nutritious (has lots of substrate)
Describe the climate of the RC system:
Variable but largely anaerobic climate
What allows the RC system to be largely protected from the host defenses?
Due to lack of circulation in disease pulpT
What does the lack of circulation in diseased pulp allow for?
The area to be protected from the host defenses
Because the root canal system of a disease pulp does not have circulation allowing it to evade host defenses, it is considered a:
Privileged sanctuary
The basic science most closely associated with the practice of endodontics:
Microbiology
By using a special “anaerobic glove box” technique, ________ bacteria were successfully culture from _____
Anaerobic; the canal system
Sundqvist, ‘76 proved that many of the pathological bacteria found in the RC system are:
Black pigmented anaerobic gram negative rods
The black pigmented anaerobic gram negative rods found to be pathogenic in the canal system by Sundqvist include (6):
- Porphyromonas
- Prevotella Nigrescens (most frequent in endo infections)
- Peptostreptococcus
- Fusobacterium
- Eubacterium
- Actinomyces
The black pigmented anaerobic gram negative rods found to be pathogenic bacteria in the canal systems by Sundqvist release ____ also known as _____ that cause: (3)
Lipopolysaccharides (LPS); endotoxins
Cause: Fever, Collagenolysis, osteolysis
The LPS (also known as endotoxins) released by the black pigmented anaerobic rods can cause:
- fever
- collagenolysis
- osteolysis
The root canal walls/spaces are conductive for the formation of:
Biofilm
A complex, colonized community of bacteria:
Biofilm
In an infection, ____ is adhered to root canal walls
Biofilm
“Floating bacteria”:
Planktonic
Riccuci sates that with apical periodontitis:
NO single microorganism is responsible
Progression of RC system infection:
- Carious lesion or trauma opens tubules to ______
- Bacterial inflame the ______
- _____ may overcome pulpal defenses and _____ may form in the ______
- Infection increases in pulp and ______ begins
- _____ involves the entire ____
- Infection uses “portals of exit” (_____ and ____) to invade ______ (______)
- _____ infection occurs beyond the ____ (____)
- bacterial invasion
- pulp locally
- inflammation; localized abscesses; coronal pulp
- necrosis
- necrosis; entire RC system
- apical foramen & lateral canals; peri-radicular tissues; apical periodontitis
- periradicular; apex; apical abscess
During the progression of RC system infections:
What causes the tubules to open allowing for bacterial invasion?
Carious lesion or trauma
During the progression of RC system infections:
What is the significance of a carious lesion or trauma?
opens the tubules to bacterial invasion
During the progression of RC system infections:
Initially, where does inflammation from the bacteria occur?
locally within the pulp
During the progression of RC system infections:
What happens when inflammation overcomes the pulpal defenses?
Localized abscesses may form in coronal pulp
During the progression of RC system infections:
Localized abscesses may form in the coronal pulp once what occurs?
Once inflammation overcomes the pulpal defenses
During the progression of RC system infections:
When localized abscesses form due to the inflammation overcoming the pulpal defenses, where are these abscesses forming?
Coronal pulp
During the progression of RC system infections:
Once infection increases in the pulp, what may begin?
Necrosis
During the progression of RC system infections:
The process of necrosis involves:
The entire RC system
During the progression of RC system infections:
What are the “portals of exit” used by the infection to invade peri-radicular tissues?
apical foramen & lateral canals
During the progression of RC system infections:
Once the infection invades the peri-radicular tissues this is considered:
Apical periodontitis
During the progression of RC system infections:
Where does the peri-radicular infection occur?
Beyond the apex
During the progression of RC system infections:
Describe an apical abscess:
Peri-radicular infection beyond the apex
During the progression of RC system infections:
When a peri-radicular infection occurs beyond the apex:
Apical abscess
The biofilm must accomplish 6 things to cause:
Disease within the RC system
What 6 things must a biofilm accomplish in order to cause disease within the RC system?
- MO must adhere to host surfaces
- Obtain nutrients from the host
- Mutliply
- Invade tissue
- Overcome host defenses
- Induce tissue damage
How could we describe a biofilm?
- Complex
- Variable
- Constantly changing
A multicellular microbial community characterized by cells that are firmly attached to a surface and enmeshed in a self produced matrix of extracellular polymeric substance (EPS), usually polysaccharide:
Biofilm
Biofilm are usefully enmeshed in a self produced matrix of:
Extracellular polymeric substance (EPS), usually polysaccharide
Bacteria that appear to be the most common microorganisms in primary endodontic infections:
Anaerobic gram negative
List the most common anaerobic gram negative microorganisms in primary endodontics infections:
- Porphyromonas
- Prevotella
- Propionibacterium
- Peptostreptococcus
- Streptococcus
- Actinomyces
- Olsenella
Porphyromonas
Prevotella
Propionibacterium
Peptostreptococcus
Streptococcus
Actinomyces
Olsenella
What do all of these microorganisms have in common?
Anaerobic Gram negative
The longer the infection exists within the RC system, the more ____ is consumed by bacterial activity and the more _____ the RC system environment becomes
Oxygen; anaerobic
The longer the infection exists within the RC system, the more oxygen is consumed by bacterial activity and the more anaerobic the RC environment becomes.
Therefore _____ infections within the RC system tend to favor _____ bacterial flora
chronic infections; anerobic
Explain why chronic infections within the RC system tend to favor anaerobic bacterial flora:
Because the longer the infection exists within the RC, the more the bacteria consume the oxygen leaving the RC environment to be more anaerobic
What type of bacteria do chronic infections in the RC system favor?
anaerobic bacterial flora
As a rule _______ is responsible for an endo infection
NO ONE organism
All endo infections are ______ (____)
mixed; polymicrobial
Endo infections are mostly caused by ____ & ____ _____
Facultative & Obligate anaerobes
Aerobes which can also survive in an anaerobic environment:
Facultative anaerobes
Facultative anaerobes may become more numerous & virulent with:
The addition of oxygen
Bacterial species that must have anaerobic environment to survive:
Obligate anaerobe
Bacterial species that CANNOT survive in aerobic environments:
Obligate anaerobe
______ liberates O2
NaOCl
Biofilm becomes more varied, complex, and difficult to control when the tooth is further challenged by _______ Or ____ (_________)
Salivary contact or operative contamination (New BUGS or altered environement)
____ becomes more varied, complex, and difficult to control when the tooth is further challenged by salivary contact or operative contamination (new BUGS or altered environment)
biofilm
Biofilm becomes more varied, complex, and difficult to control when the tooth is further challenged by salivary contact or operative contamination (new BUGS or altered environment)
SO _______ of rubber dam or temporary AND ______ during treatment (leaky dental dam, etc.)
avoid leakage; avoid iatrogenic contamination
How do we destroy the bacteria in RC treatment?
8.3% Sodium Hypochlorite (NaOCl)
Our major weapons in destroying bacteria in RC system”
Cleaning and shaping with NaOCl and Intra-canal medications
How does the NaOCl work to kill RC bacteria?
Kills directly or starves them out
What makes some RCs resistant to mechanical shaping?
Diverse shapes
(Files never reach ALL spaces in the complex pulpal system)
What implication does the diverse shape of RCs have on mechanical shaping?
Files never reach ALL spaces in the complex pulpal system