Endodontics - materials

Question 1

What irrigants are used in GDH

Answer 1

• sodium hypochlorite
• edta
• chlorhexidine digluconate
• sterile saline

Question 2

What is the brand name for the sodium hypochlorite used within the dental school

Answer 2

parcan

Question 3

What concentration is the sodium hypochlorite used in the GDH

Answer 3

3%

Question 4

What is sodium hypochlorite’s mode of action

Answer 4

• ionises in water to produce sodium ion and hypochlorite forming an equilibria with hypochlorous acid
• above ph9 hypochlorite predominates and is responsible for the anti bacterial activity

Question 5

What is the purpose of sodium hypochlorite

Answer 5

• potent antimicrobial activity
• dissolves pulp remnants and collagen
• disrupts the smear layer by acting on the organic component

Question 6

What makes sodium hypochlorite better than other irrigants

Answer 6

it is the only one that dissolves both necrotic and vital tissue

Question 7

What is the protocol for sodium hypochlorite

Answer 7

1. 3% rinse with NaOCl throughout instrumentation
2. 30ml rinse once instrumentation is complete for at least 10 minutes prior to obturation
3. final rinse after EDTA

Question 8

What concentration of sodium hypochlorite provides effective antimicrobial activity

Answer 8

0.5-6%

Question 9

What are the risks associated with sodium hypochlorite

Answer 9

1. effects on dentine integrity
2. cannot disrupt the smear layer itself
3. effect on organic material
4. extrusion into surrounding tissues
5. opthalmic issue if contact with eyes
6. allergic reaction

Question 10

What factors of sodium hypochlorite are important for its function

Answer 10

• concentration
• volume
• contact
• mechanical agitation
• exchange

Question 11

You are mid-way through your RCT and your patient starts complaining of pain and you notice swelling

What are these symptoms indicative of

Answer 11

they are symptoms of hypochlorite extrusion

Question 12

What are symptoms of hypochlorite extrusion

Answer 12

• pain
• swelling
• ecchymosis
• hemorrhage
• neurological complications
• airway obsructions

Question 13

What are risk factors for extrusion

Answer 13

• excessive pressure during irrigation
• needle locked within canal
• loss of control of working length
• larger apical diameters/constrictions

Question 14

How should you manage an extrusion

Answer 14

STOP

use steroid containing intracanal medicament and place it in root canal

do not use pressure

Question 15

What concentration of EDTA is used

Answer 15

17%

Question 16

What is the purpose of EDTA

Answer 16

removing the smear layer

it is a chelating agent

Question 17

What is the protocol for EDTA

Answer 17

1 minute penultimate rinse with EDTA before NaOCl final rinse to remove smear layer formed

Question 18

What should EDTA not be used at the same time with

Answer 18

NaOCl

Question 19

Why should hypochlorite and EDTA not be used at the same time

Answer 19

• hypochlorite is a demineralizing agent and EDTA is a chelating agent so the two used together will have a profound impact on the dentine

Question 20

What are the two concentrations of chlorhexidine used within the dental school

Answer 20

0.2% and 2%

Question 21

What is the function of 0.2% chlorhexidine

Answer 21

to test the dental dam seal

to disinfect the tooth surface

Question 22

What is the brand name for 0.2% chlorhexidine

Answer 22

corsodyl

Question 23

What is the mode of action of chlorhexidine

Answer 23

• positively charged CHX molecules are attracted to the negatively charged phospholipids in the cell wall
• this causes the CHX to bind and cause the cell wall to rupture
• the cytoplasm then leaks causing cell death

Question 24

What are the properties of chlorhexidine as an irrigant

Answer 24

• antibacterial activity shows conflicting results
• less antifungal acitvity than NaOCl
• somewhat active against biofilms but unable to disrupt them
• absorption of CHX prevents microbial colonisation beyond the time of application, varying times of up to 12 weeks

Question 25

What is the protocol for chlorhexidine

Answer 25

replace with CHX

Question 26

What are risks associated with chlorhexidine

Answer 26

* biocompatiibility is considered acceptable but CHX sensitivity is possible * risk of anaphylaxis * potential interaction with NaOCl - DANGEROUS

Question 27

Why shouldnt NaOCl and chlorhexidine be used at together

Answer 27

together they form para-chloraniline and it is cytotoxic and carcinogenic

Question 28

What should be done after doing the 10 minute soak with NaOCl

Answer 28

EDTA but **first dry with paper points**

Question 29

What is the brand name for sterile saline

Answer 29

baxter

Question 30

What is sterile saline used for

Answer 30

washing out canal after hypochlorite accident is supected

Question 31

What are the different intra canal medicaments

Answer 31

antimicrobial paste non setting caoh inter appointment temp dressing

Question 32

What is the brand name for antimicrobial paste

Answer 32

odontopaste

Question 33

What are the contents of odontopaste

Answer 33

corticosteroid for anti-inflammatory tetracycline antiobiotic paste

Question 34

What is the purpose of antimicrobial paste

Answer 34

hot pulp - will allow for instrumentation next appointment Hot pulp = pulp so imflamed that you can't achieve anaesthesia

Question 35

How long is antimicrobial paste effective for

Answer 35

5-7 days

Question 36

What are the useful properties of CaOh as a intra canal medicament

Answer 36

* high pH to reduce bacterial activity * prolonged antibacterial activity * hydrolysis of LPS to reduce inflammatory potential * effective for removing tissue debris * combined with NaOCl it improves cleaning ability

Question 37

What are the different inter appointment temporary dressings

Answer 37

1. cavit 2. irm 3. GIC 4. coltosol (removed with ultrasonic)

Question 38

What does an inter appointment temp dressing go

Answer 38

seals the canal between appointments to prevent bacteiral ingress

Question 39

What are the contents of GP

Answer 39

* 20% GP * 65% ZnO * 10% radiopacifier * 5% plasticiser

Question 40

What is the purpose of gutta purcha

Answer 40

* fill the root canal system in 3 directions * fill space * prevent bacterial colonisation

Question 41

What are the different sealers

Answer 41

* ZOE * GI sealer * resin sealer * calcium silicate sealer

Question 42

What is the purpose of sealer

Answer 42

* fill the space between dentine, wall and core * fill voids, irregularities, lateral canals and between GP points * lubricates GP cones for obturation

Question 43

Why is ZOE good as a sealer

Answer 43

effective antimicrobial effect offers cytoprotection strongly cytotoxic

Question 44

What is the good things about GI sealer

Answer 44

dentine bonding properties

Question 45

What are the good things about resin sealer

Answer 45

* slow set of 8 hours * good sealing ability * good flow * initial toxicity declining after 34h * hydrpohilic so good penetration into tubules * biocompatible * good radiopacity

Question 46

What are the good things about calcium silicate as a sealer

Answer 46

* high ph 12.8 in initial 24h set * hydrophilic * enhanced biocompatibility * does not shrink on setting * non-resorbable * excellent sealing ability * quick set * easy to use

Question 47

What are the limitations of ZOE as a sealer

Answer 47

* free eugenol remains and can act as an irritant * loses volume over time due to dissolution * hard to remove from the canal

Question 48

What are limitations of glass ionomer sealer

Answer 48

* minimal antimicrobial activity * greater solubility * removal is difficult * little clinical data to support its use