ROOT CANAL IRRIGATION AND DISINFECTION

Question 1

what is required for periapical and pulpal infections

Answer 1

do not develop without the presence of bacteria

primary root canal infections are polymicrobaol

Question 2

aims of irrigation

Answer 2

1) killing and removal of microorganism
2) removal of necrotic/inflamed tissue
3) removal of dentine debris and smear layer
4) provide lubrication and reduced friction for instrumentation

Question 3

obstacles in root canal disinfections

Answer 3

1) anatomical complexities
2) smear layer
3) fluid dynamics
4) biofilm and resistance microbiota

Question 4

what does the smear layer consist of

Answer 4

• inorganic substances
• organics
• fragments of odontoblastic processes
• microorganisms
• necrotic debris

Question 5

problems associated with smear layer

Answer 5

• provides protection for bacteria

- inhibits/delays penetration of irrigant into dentinal tubules

Question 6

how is the smear layer created

Answer 6

during cleaning and shaping

Question 7

fluid motion

Answer 7

irrigant only penetrates 1-2mm further than the end of the needle therfore needs to be close to the apical region

Question 8

stagnation plane

Answer 8

area where there is no fluid movemnet

Question 9

rules of irrigation (fluid dynamics)

Answer 9

side venting needle
keep the needle moving to prevent wedging and forcing irrigant through apex
if needle binds stop and pull back
keep 2-3m away from apex, 3/4 if open apex

Question 10

dynamic pumping

Answer 10

use of gutta percha point to improve irrigant exchange in apical region

Question 11

biofilm

Answer 11

group of microorganisms in which cells stick to each other on a. surface
emebedded in EPS
(generalyl DNA, proteins and polysaccharide)
- on the internal wall of dentine

Question 12

resistant bacterai

Answer 12

E faecalis
- found in retreatment cases
resisyant to NaOCl

Question 13

ideal characteristics of endo irrigatn

Answer 13

effective antimicrobal action
non irritating to pulp tissue
stable
prolonged antimicrobail effect
active in presence of blood ect
low surface tension
not stain tooth structure
not induce cell immune responce
able to remove smear layer

Question 14

basic principles of irrigation involves

Answer 14

mechanical and chemical irrigation

mechanical pre needs to be sufficient to allow irrigant penetration

Question 15

sodium hypochlorite

Answer 15

NaOCl
- dissolves organic matter inc biofilm
antimicribial 
affordable
need continous replenishment

Question 16

disadvantages of sodium hypochloride

Answer 16

1) minimally removes dentine debris or smear layer
2) affects mechanical dentine properties (Reduces flexular strength)
3) rare cares allergic reaction dermatitis
4) toxic to vital tissue ( hemolysis, epithelial ulceration and necrosis)
5) causes corrosion to metal

Question 17

EDTA

Answer 17

1) solution 17%
- should be used as a penultimate rinse for approx. 1-2mins
2) gel
- can help in sclerosed canals
- aids lubrication

synthetic aa
- removes smear layer as it is a chelating agent
non toxic
not bacterialcidal or static

over use is excessive removal dentine

Question 18

chlorhexidine

Answer 18

histoircal

• bacteriocidal/static

can form a ppt with NaOCl
cannot remove smear layer
allergy

Question 19

iodine potassium iodide

Answer 19

historical
acts as an oxidising agent that attacks key group protiens neucelotides etc

broad spectrum

allergy
can stain dentine
not stabale with organic material

Question 20

hydroghen peroxides

Answer 20

historucal
destroys protien DNA

active agaisnt bacteria
less tissue disolving and antimicrobail efficacy compared to NaOCl

Question 21

protocol for irrigation in CCDH

Answer 21

NaOcl followed by EDTA as final flush

Question 22

ultrasonic activation of irrigants

Answer 22

can be activated ultrasonically
enhances antibacterial efficiency
disrupts biofilm