Canal Disinfection

Question 1

Key for successful endo bc the files can’t reach all the walls of the canal.

Answer 1

Thorough irrigation

Question 2

Ideal irrigant has high or low surface tension?

Answer 2

LOW- so it can spread to all the surfaces of the canal.

Question 3

Types of Irrigants

Answer 3

NaOCl
EDTA
CHX

Question 4

NaOCl alkaline or acidic?

Answer 4

Alkaline

Question 5

The gold standard irrigant that:

• dissolves both vital and necrotic tissue,
• removes the organic component of the smear layer,
• kills bacteria,
• eliminates biofilm
• Lubricating action
• Cytotoxic

Answer 5

NaOCl

Question 6

NaOCl mechanism of action

Answer 6

• Saponification
• Amino acid neutralization
• Chloramination
• Alkaline pH (>11)
• Hydrolysis

Question 7

A fatty acid is heated with an alkali to make soap and alcohol.

Answer 7

Saponification

Question 8

A chemical species that donates an electron pair to an electrophile to form a chemical bond; it’s electron rich.

Answer 8

Nucleophile

Question 9

Nucleophiles work during this step of NaOCl’s MOA.

Answer 9

Saponification

Question 10

An acid-base reaction, which yields a salt and water.

Answer 10

Amino acid neutralization

Question 11

A rxn where chloramines are made from Chlorine and Ammonia

Answer 11

Chloramination

Question 12

This pH (specifically, these IONS) alters the cell membrane by loss of phospholipids and fatty acids.

Disrupts cellular processes and enzymatic activity.

Answer 12

Alkaline ; OH- ions

Question 13

Substance that dissolves tissue into soap and glycerol via saponification.

Answer 13

NaOCl

Question 14

This product of NaOCl MOA interferes with cellular metabolism.

Answer 14

Chloramines

Question 15

This disinfectant irreversibly inactivates essential bacterial enzymes via oxidation of sulfhydryl groups by Chlorine.

Answer 15

NaOCl

Question 16

This is used as a chelating agent (underlined) in root canals to remove calcium, demineralize and soften dentin, and remove the smear layer.

Answer 16

EDTA

Question 17

Used to negotiate calcified canals.

Answer 17

EDTA

Question 18

Removing this increases Ca(OH)2 diffusion through the tubules, and increases tubule penetration by the sealer.

Answer 18

Smear layer

Question 19

This irrigant is followed by a final rinse of NaOCl so the bleach can kill the bacteria in the tubules.

Answer 19

EDTA

Question 20

A bis-biguanide antiseptic used to prevent colonization of microbes and to kill microorganisms on surfaces;
known for its substantivity.

Answer 20

Chlorhexidine

Question 21

Definition: The binding of disinfectant to dentin and soft tissue with prolonged release.
Gives residual antimicrobial activity for a long time.

Answer 21

Substantivity

Question 22

This substance:

• Kills bacteria
• Does NOT dissolve pulp tissue.
• Does NOT eliminate biofilm
• Does NOT remove the smear layer

Answer 22

CHX

Question 23

Do not mix these two irrigants together.

Answer 23

NaOCl and CHX

Question 24

CHX MOA.

Answer 24

Positively charged CHX binds to Negatively charged phosphates in the bacterial cell wall, creating pores that disrupt the cell’s osmotic equilibrium, and the cell lyses.

Question 25

A gas bubble of NH3 and CO2 forms at the apical canal by hydrolysis of organic tissue, making it impossible to irrigate the most apical part of the canal.

Answer 25

Vapor lock

Question 26

Which canals get vapor lock?

Answer 26

Closed

Question 27

T/F: higher concentrations of NaOCl will dissolve tissue faster and increase antimicrobial effectiveness.

Answer 27

True

Question 28

When is the only time the canal should be dry?

Answer 28

When ready to place the sealer.

Question 29

T/F: increasing NaOCl temperature before irrigating will increase its effectiveness.

Answer 29

True

Question 30

What's this process called: agitating the bleach into uninstrumentable portions of the canal.

Answer 30

Activation

Question 31

Cannot do this to the irrigant around root curvatures bc the metal tip will create procedural errors.

Answer 31

Activation

Question 32

Definition: Activation of fluid and hydrodynamic shear forces near a small vibrating object.

Answer 32

Acoustic streaming

Question 33

Definition: Use the alternating high frequency movement of an instrument tip to form submicroscopic voids. These voids implode and make shock waves that spread through the medium.

Answer 33

Cavitation.

Question 34

This SONIC device is used for activation of the irrigant. Uses polymer tips, which are safe to use around curvatures. Not as strong as ultrasonics. Does NOT create cavitation.

Answer 34

EndoActivator

Question 35

Has low frequency (1500-6000 Hz) and high amplitude

Answer 35

Sonic

Question 36

Has High frequency ( >20,000) and low amplitude.

Answer 36

Ultrasonic

Question 37

Forms when you mix CHX and NaOCl.

Answer 37

PCA (para-chloroaniline)

Question 38

PCA is _____.

Answer 38

carcinogenic.

Question 39

This irrigant inhibits NaOCl by reducing the amount of free Chlorine.

Answer 39

EDTA Reduces the amt of free Chlorine bc it's a chelating agent.

Question 40

This doesn't lose its chelating ability when mixed with NaOCl.

Answer 40

EDTA

Question 41

Mixing these two irrigants makes a salt, which is harmless.

Answer 41

CHX and EDTA

Question 42

Which intracanal medicament is this: - Alkaline pH - Bactericidal - Dissolves pulp tissue - Stimulates hard tissue formation - Resorbable - Eliminates biofilm?

Answer 42

Ca(OH)2

Question 43

Ca(OH)2 MOA:

Answer 43

1) Damages the cytoplasmic membrane 2) Protein denaturation 3) Damage to DNA

Question 44

How long does it take for Ca(OH)2 to get rid of most of the bacteria in the canal?

Answer 44

1 week; is NOT effective short-term.

Question 45

This material does reduce the bacterial load, but has not been shwon to increase outcomes.

Answer 45

Ca(OH)2