week 3

Question 1

when do rotating files cut

Answer 1

on the out stroke

Question 2

what are some limitations of apex locators

Answer 2

might incorrectly report the WL

Question 3

what else do we use to determine working length

Answer 3

x rays

Question 4

where is the apical constriction

Answer 4

1-2mm back from the apical foramen

Question 5

why do we need to determine the WL correctly

Answer 5

to stop overextension
overpreperation
allow

Question 6

how to use an apex locator

Answer 6

1) Connect the lip hook to the alginate block and connect to the metal shaft of the file
2) Place a 10/15 file into the canal and work it down until it is just through the apex( over reading on the Denstply)
3) Rotate the file back until it shows that we are no longer through the apex
4) Identify an accurate reference point usually a cusp and push the stopped down into it
WL is taken as 0.5mm short of the zero reading using the measured file length to prevent damage to the apical constriction

Question 7

why do we need to temporise

Answer 7

• Endodontic procedures are often lengthy procedures so we cannot complete them in one visit
  
  • Having disinfected the canals we do not want bacteria to enter so we have to try to keep the canals clean
  • The mouth is full of bacteria so we need to seal it effectively

Question 8

what do we use as a medicament

Answer 8

calcium hydroxide

Question 9

why do we use calcium hydroxide

Answer 9

• A high pH of 12.5- very bactericidal and stimulates healing of bony lesions
Radiopaque due to barium sulphate being added

Question 10

what is beneficial about calcium hydroxide

Answer 10

it is radiopaque due to barium sulphate added

Question 11

what else do w use to seal the prep

Answer 11

cotton wool pledget

Question 12

what do we use as a temporary filling material

Answer 12

zinc reinforced GIC- chemfil rock

Question 13

why do we use chemfil rock

Answer 13

→ It is self curing 
	→ Sets quickly 
	→ Packable 
	→ Strong 
	→ Good radiopacity 
And good contrast- as it is light pink

Question 14

how do we apply chemfil rock

Answer 14

1) Activate for 2s
2) Mix in amalgamator for 15s
3) Place in gun and apply
4) Pack and shape- working time is 1min 30sec
Setting time 6 mins

Question 15

why do we need to irrigate

Answer 15

→ For the dissolution of organic tissue and pulpal remnants
→ Dissolution of select inorganic components
→ Killing of microorganisms and neutralising endotoxin
→ Lubricate canals
As instrumentation cannot reach all aspects of the canal we rely on irrigation to clean hard to reach areas

Question 16

does the naclo remove the smear layer

Answer 16

no

only EDTA does

Question 17

what do we do incase of a hypochlorite incident

Answer 17

→ Prevention is better than cure
→ Small amounts are not harmful but will cause mucosal irritation and a bad taste
Signs and symptoms of extrusion-sudden pain even with LA, profuse bleeding from the canal and extensive oedema