Endodontic Disinfection

Question 1

instrumentation fails to:

Answer 1

contact a large portion of the hidden spaces which are filled with bacteria and substrate

Question 2

what needs to be removed from canal for RCT to be successful

Answer 2

remove and destory bacteria and their sbustrate

Question 3

what percentage of areas can be accessed with instrumentation

Answer 3

60-70%

Question 4

since not all areas can be accessed with instruments what is used in adjunct with it

Answer 4

• 8.3% sodium hypochlorite (NaOCl)

Question 5

what do we clean and shape with

Answer 5

NaOCl and intra canal medicaments

Question 6

how long should the needle be

Answer 6

2mm from working length

Question 7

should the needle be bent or straight

Answer 7

bent

Question 8

tip of syringe cannot pass beyond:

Answer 8

apical constriction

Question 9

do not allow tip to ____ in the canal

Answer 9

bind

Question 10

what does NaOCl do

Answer 10

• kills micro-organisms on contacts
• destroys and dissolves substrate
• disorganizes biofilm
• dilutes toxins in canal system
• disinfects RC system and instruments
• lburicates canals
• floats out debris

Question 11

when NaOCl breaks down what do we have

Answer 11

NaCl and water

Question 12

when does NaOCl break down

Answer 12

in the bottle and in the tooth

Question 13

how long does it take for NaOCl to become inactive in the canal and when does it need to be replenished

Answer 13

after 3-5 minutes so it must be replenished every 3-5 minutes

Question 14

irrigate following:

Answer 14

each active instrument

Question 15

what is used for surface disinfection and what is the concentration of NaOCl

Answer 15

• Dakin’s solution
• 0.25%

Question 16

what concentration of NaOCl do we use and how does it compare to Dakins solution

Answer 16

• 8.3%
• it is stronger and more toxic and more effective

Question 17

typical case requires ____ of NaOCL as irrigant per visit

Answer 17

10-12cc

Question 18

NaOCl must be in contact with shaped canal a minimum of _______ after canal enlarged to a ___ or larger

Answer 18

• 30 minutes
• # 30

Question 19

what does recapitulate mean

Answer 19

-flood canal system with NaOCl
- do this every 3-5 minutes
- then move on with next active instrument

Question 20

when should you recapitulate

Answer 20

following each active instrument

Question 21

how big is the syringe we get

Answer 21

12cc

Question 22

describe sodium hypochlorite

Answer 22

• strong oxidizer
• powerful disinfectant
• dissolves necrotic tissue at low concentration
• dissolves living tissue at higher concentration
• med of choice in endo

Question 23

describe sodium hypochlorite

Answer 23

• strong oxidizer
• powerful disinfectant
• dangerous and extremely toxic

Question 24

what do you do if sodium hypoclorite is swallowed

Answer 24

• call poison center
• dental dam must not leak

Question 25

what do you do if contact with eyes and sodium hypochlorite

Answer 25

flush with water for 15 minutes - never forget eye protection and never pass anything over face

Question 26

even with special tip:

Answer 26

- vigorous infection will cause irrgant to express apicaly - be carefule - do not let the tip bend - keep moving and loose in canal - tastes terrible in mouth and burns throat - dental dam must not leak

Question 27

what happens if irrigating needle is allowed to bind in canal

Answer 27

NaOCl can be forced out the end of the tooth into the PA tissues with disastrous results

Question 28

what are the results of NaOCl leaking into PA tissues

Answer 28

- immediate and extreme pain for several days - ecchymosis -swelling - temporary disfigurement

Question 29

can you undo NaOCl accidents

Answer 29

no you can only prevent them

Question 30

why do you need to protect clothing

Answer 30

the tip od the syringe will leak as you remove it from the tooth

Question 31

what does dr edwards suggest you do to protect clothes

Answer 31

place your gloved hand under the syringe as you remove it from the tooth

Question 32

what does the sonic vibration of NaOCl endo activator do

Answer 32

- agitates irrigation solutions during endo treatment - cavitation and acoustic streaming significantly improves debridement and the disruption of the smear layer and biofilm

Question 33

when would the endo activator be helpful

Answer 33

in difficult and unusual canal systems

Question 34

does endo activator diminish time for use of NaOCl

Answer 34

no

Question 35

when is the smear layer produced

Answer 35

when we do any mechanical shaping in dentin

Question 36

where is the smear layer

Answer 36

on the surface of dentinal tubules

Question 37

is the smear layer removed by NaOCl

Answer 37

no

Question 38

when should the smear layer be removed

Answer 38

before obturation or when using various sealers and cements to complete the cleaning procedure and to be able to access dentinal tubules

Question 39

what is used to remove smear layer and for how long

Answer 39

17% EDTA and works for 60 seconds

Question 40

what stops the action of EDTA

Answer 40

8.3% NaOCl

Question 41

what does EDTA stand for

Answer 41

ethylene diamine tetra-acetic acid

Question 41

what other irrigant is enouraged

Answer 41

2% chlorhexidine

Question 42

why dont we think 2% chlorhexidine is necessary

Answer 42

no biofilm removal, precipitate formation

Question 43

can we sterilize the RCS

Answer 43

no we can lower bacterial concentrations

Question 44

when are intracanal medications placed

Answer 44

within the canal system between appointments

Question 45

what is the goal of intracanal medications

Answer 45

increase local anti-microbial action and to further decrease the microbial challenge within the RC system

Question 46

what is the intracanal medication of choice

Answer 46

Ca(OH)2

Question 47

describe CaOH2

Answer 47

- ph between 11 and 12 - discourages most microbial growth - long lasting- effectiv eover extended periods - no reported allergic responses - easy to apply and remove as a paste - available in clinic as ultracal

Question 48

all potential portals of entry/exit must be:

Answer 48

sealed creating a dense liquid tight (hermetic) seal "obturation" and final restoration to prevent leakage

Question 49

what are we theoretically sealing in the canal

Answer 49

some micro organisms, toxins and substrate within the canal system

Question 50

what are the main take home messages

Answer 50

- use NaOCl to dissolve organic tissue and to kill microorganisms - use a needle that fits loosely 2mm from WL. irrigate with an in and out gentle movment - replenish NaOCl every 3-5 minutes/after every active instrument - EDTA removes inorganic portion of the smear layer - CaOH: intracanal medication of choice- pH between 11 and 12