Endodontics

Question 1

pain fibres associated with reversible pulpitis

Answer 1

a delta

Question 2

pain fibres associated with irreversible pulpitis

Answer 2

c fibre

Question 3

features of an ideal irrigant

Answer 3

flushes bedris
kills microorganism's 
dissolves organic matter
lubricates
non toxic
inexpensive

Question 4

advantages + disadvantages of sodium hypochlorite (0.5-5%)

Answer 4

+ = flushes, antimicrobial, tissue solvent, lubricant, inexpensive

• = irritant

Question 5

advantages + disadvantages of chlorhexidine gluconate as irrigant (0.2-2%)

Answer 5

+ = flushes, antimicrobial, lubricant, non-irritant

• = expensive, no solvent

Question 6

advantages + disadvantages of saline/water/LA as irrigant

Answer 6

\+ = flushes, lurbricant, non irritant
- = no antimicrobial or solvent

Question 7

3 options for antimicrobial dressing material between appointments

Answer 7

1. CaHO2 non setting
2. chlorhexidine gel
3. odontopaste (ledermix)

Question 8

features of odontopaste/ledermix

Answer 8

steroid/antibiotic
antimicrobial (CaOH2 + clindamycin hydrocholride)

good if LA was not successful when accessing (hyperaemic pulp) - reduces inflammation for next visit

Question 9

features of CaOH2

Answer 9

pH11/12
broad spectrum antimicrobial - up to 3 month
dissolves organic debris

Question 10

how thick must temporary filing material be

Answer 10

3mm

Question 11

4 options for temporary filling material

Answer 11

1. cavit
2. sedanol
3. IRM
4. GIC

Question 12

how to protect canal when temporary filling

Answer 12

cotton wool, sponge, PTFE tape

Question 13

features of cavit

Answer 13

plaster of Paris + PDA
sets in contact with saliva
good seal in retentive non-load bearing sites
easy to remove

Question 14

features of sedanol

Answer 14

good seal

good in retentive non-load bearing sites

Question 15

features of IRM

Answer 15

ZnOE cement reinforced for PMM
stronger for load bearing sites - last 1yr
easy to remove

Question 16

features of GIC

Answer 16

good for unretentive + load bearing site

difficult to remove

Question 17

what are chelating agents used for?

Answer 17

soften dentine by demineralising - useful when trying to negotiate sclerosed/blocked canals

e.g. EDTA paste

Question 18

5 examples of sealer cements

Answer 18

1. CaOH2
2. ZnOE
3. resin
4. calcium silicate
5. silicone

Question 19

disadvantage of MTA

Answer 19

can cause grey discolouration

Question 20

4 basic requirements of access cavity

Answer 20

1. pulp chamber fully unroofed
2. straight line access
3. no unnecessary tissue removal
4. sufficient retention

Question 21

at what depth should you find pulp chamber

Answer 21

6-7mm

Question 22

tradiotoanl and contemporary approach to shaping

Answer 22

trad = iso stainless steel instruments - 5-10% taper by stepping back 0.5-1mm increments

contemporary = NiTi instruments - predictable taper

Question 23

difference between stainless steel + NiTI

Answer 23

stainless steel = precurved (use for ledges)

Question 24

process causing pulp to become necrotic following infection

Answer 24

1. increase in pulpal pressure due to oedema
2. venous stasis
3. causes ischamia + thrombosis
4. necrosis

Question 25

how does pulpitis in a tooth with an open apex present?

Answer 25

open pulpitis - good apical blood supply causes hyperplastic granulation tissue pulp polyp - chronic hyperplastic pulpitis (bleeds on probing)

Question 26

types of pulp calcifications

Answer 26

diffuse/dystrophic pulp stones (denticles) - coronal, true pulp, false pulp, irregular or laminated, free/adherent/interstitial

Question 27

what is a true pulp stone

Answer 27

rare, caused by odontoblasts

Question 28

what is a false pulp stone

Answer 28

concentric layers of mineralised tissue around blood vessel

Question 29

4 vital pulp therapies

Answer 29

1. indirect pulp cap 2. direct pulp cap 3. pulpotomy 4. pulp revitalisation for teeth with deep caries but no signs of irreversible pulpitis

Question 30

in stepwise excavation when do you re-enter?

Answer 30

6 weeks

Question 31

what sort of dentine is made in direct pulp capping?

Answer 31

odontoblast like cells migrate in - reparative tertiary dentine

Question 32

if accidentally expose pulp how do you proceed

Answer 32

isolate haemostats - sodium hypochlorite to remove micro-organisms consider direct pulp capping or pulpotomy

Question 33

3 main reasons for RCT

Answer 33

1. irreversible pulpitis 2. placement of crown/bridge, later access would be hard 3. teeth that would be unrestorable without retention from pulp space

Question 34

if you can not dry canal how should you proceed?

Answer 34

recline apply non-setting caOH2 seal access review 1-2 weeks

Question 35

how much supra gingival tooth tissue needs to be left for a successful ferrule?

Answer 35

2-3mm circumferential dentine, ideally extending parallel

Question 36

where should restoration margins be in order to be a success?

Answer 36

on tooth tissue

Question 37

disadvantage to using amalgam core

Answer 37

delayed crown/onlay prep - takes 24hours to set only posterior teeth

Question 38

how much GP is removed using gates gladden for Nayyar (amalgam) core?

Answer 38

3-4mm

Question 39

2 core options for posterior teeth

Answer 39

composite or amalgam (nayyar) avoid using posts

Question 40

common materials for direct posts

Answer 40

fibre (most common) pre-formed metallic - ss, titanium ceramic - epoxy resin

Question 41

what material are indirect posts normally made from?

Answer 41

cast metal

Question 42

steps for indirect post

Answer 42

1. prepare post channel + coronal tissue 2. insert smooth, plastic impression post + record impression 3. make temp post crown with smooth metal temp crown post 4. send impression to lab + cast 5. remove smooth impression post from model 6. insert size matched plastic, serrated burnout post + wax up core 7. remove pattern from model + cast in metal 8. fit + cement post 9. impression for permanent crown

Question 43

how much apical root filling needs to retain to provide seal?

Answer 43

4-5mm

Question 44

shape + length of posts

Answer 44

longer + wider + parallel posts more retentive

Question 45

3 cementation options for posts in increasing retention

Answer 45

zinc phosphate (always for metal) GIC/RMGIC composite (always for fibre)

Question 46

3 radiographic feature of peri apical periodontitis

Answer 46

1. PAP 2. widening of PMS 3. loss of lamina dura

Question 47

4 outcomes of periapical periodontist

Answer 47

1. resolution 2. periapical granuloma 3. focal sclerosis osteitis 4. dentoalveolar abscess also inflammatory root resorption, hypercemtnosis, ankylosis, radicular cyst

Question 48

radiograph appearance of hypercementosis

Answer 48

bulbous root

Question 49

what causes a radicular cyst

Answer 49

necrotic pulp/non vital tooth pathological cavity containing fluid (not pus), lined by epithelium proliferation of cell rests of malaise stimulated by inflammatory mediators epithelial proliferation, bone resorption, osmotic pressure

Question 50

clinical presentation of radicular cyst

Answer 50

asymptomatic or symptomatic +/- swelling tooth mobility, displacement

Question 51

radiographic appearance of radicular cyst

Answer 51

round, unilocular well defined, corticated radiolucent causes root resorption

Question 52

types of radicular cyst

Answer 52

pocket (more likely to heal) or true apical, lateral or residual if left after extraction

Question 53

treatment for radiuclar cyst

Answer 53

most heal after RCT