Disinfection Flashcards
3 organisms that are primarily present in root filled teeth?
- Enterococci (29-77%)
- Candida
- Actinomyces
What are the two “main” functions of root canal irrigants? Give named examples.
- Antimicrobial (sodium hypochlorite, 2% chlorhexidine -historical).
- Remove smear layer (citric acid, 17% EDTA)
Which root canal irrigants are antimicrobial?
- Sodium hypochlorite
- 2% chlorhexidine.
Which root canal irrigants remove the smear layer?
- Citric acid
- 17% EDTA
EDTA?
Ethyldiaminetetraacetic acid
What organisms does sodium hypochlorite act against?
- BROAD SPECTRUM: bacteria, fungi, spores, viruses.
What give sodium hypochlorite its antimicrobial properties?
- Antimicrobial properties rely on FREE CHLORINE.
What is a MAJOR ADVANTAGE of sodium hypochlorite?
DISSOLVES NECROTIC/ ORGANIC TISSUE.
What are 3 important procedural factors for ensuring EFFECTIVENESS OF SODIUM HYPOCHLORITE?
VOLUME, FREQUENCY, PENETRATION OF IRRIGATING NEEDLE.
What is the recommended volume of sodium hypochlorite for each canal?
20mL per canal.
What are 5 disadvantages of Sodium hypochlorite?
- Highly toxic.
- Unpleastant taste.
- Unable to remove smear layer.
- Can damage clothing.
- Can damage eyes.
4 reasons why sodium hypochlorite irrigation beyond the root apex may occur.
- Wide apical foramina.
- Apical constriction destruction (over-instrumentation, root resorption).
- Extreme pressure during irrigation.
- Binding of irrigation needle tip.
What are symptoms of a sodium hypochlorite accident (6)?
- Extreme pain, burning sensation.
- Hematoma and ecchymosis.
- Swelling.
- Profuse bleeding from root canal.
- 2nd infection and tissue necrosis.
- Paraesthesia.
What is the treatment for a sodium hypochlorite accident?
- Inform patient.
- Minimize swelling, control pain, prevent secondary infection.
- cold/warm compresses, anelgesia, antibiotics (prevent 2nd infection), refer to OS for removal of necrotic tissue.
How is the smear layer produced and what does it contain?
- Cleaning and shaping produces a layer that covers instrumented walls.
- Contains inorganic and organic substances, microorganisms, necrotic materials.
Why should the smear layer removed?
- Protects microbes from the effects of disinfectants.
- Prevents complete adaptation of obturation materials to root canal surfaces.
How does 17% EDTA remove the smear layer?
Reacts with calcium ions in dentine to form SOLUBLE CALCIUM CHELATES.
What is a disadvantage of 40% citric acid?
Can leave precipitation crystals.
What is used for endodontic irrigation (syringe etc).
- 3mL Luer lock syringe.
- 27 gauge needle with side vent.
4 steps to follow to ensure safe irrigation?
- Bend needle 2-3mm short of working length.
- Keep needle constantly moving in canal.
- Ensure needle doesn’t bind to canal.
- Put pressure with forefinger.
What is the irrigating sequence?
- Irrigate with full 3mL syringe after every rotary file.
- Recapitulate with size 10 flexofile.
- Irrigate again with 3mL syringe.
What is the irrigating sequence once preparation is complete?
- 3mL syringe sodium hypochlorite.
- 3mL syringe of citric acid.
- 3mL syringe of sodium hypochlorite.
What are the 5 functions of CaOH?
- Kills bacteria and inactivates endotoxin.
- Reduced inflammation.
- Helps eliminate apical exudate.
- Controls inflammatory root resorption.
- Prevents contamination between appointments.
How does CaOH achieve its antimicrobial activity?
- Release of OH ions in aqueous solution.
- Effects on bacterial cells (3): Damage to bacteria cytoplasmic membrane, DNA damage, protein denaturation.
