Endodontic Materials

Question 1

what is the working blade of a endo hand instrument

Answer 1

Question 2

what is the taper of a conventional SS instrument

Answer 2

2%

Question 3

what are the ISO standardises colour system for each file

Answer 3

Question 4

what is the composition of ss hand files

Answer 4

• Iron alloys with a minimum of 10.5% chromium
  Contains other metals nickel, molybedenum, titanium and copper

Question 5

what are advantages and disadvantages to ss hand files

Answer 5

• Advantages, do not readily corrode, rust or stain
  They have poor flexibility, which may lead to procedural errors during canal shaping

Question 6

how are small vs large ss hand files different in how they are made

Answer 6

Question 7

what are different types of ss files

Answer 7

• Barbed broaches
  
  • Reamers (not used anymore)
  • Files (k files, flexofile, hedstrom)

Question 8

what are barbed broaches

Answer 8

Question 9

what are flexofiles?

Answer 9

• Used for preparation of glide path, apical gauging, negotiating ledges and blockages
  
  • They have non-aggressive tip called a batt tip
  • Good flexibility
    Efficient at cutting dentine with a low risk of transportation and ledge formation

Question 10

what is the balanced force technique

Answer 10

Question 11

what are hedstroem files

Answer 11

• Very stiff files
  
  • Can only ne used in up and down motions
  • Files cut when moved in the coronal direction
    Only used in retreatment cases to help remove GP and an overfilling of the root canal

Question 12

what are disadvantages to ss files

Answer 12

• Mishaps: ledges, blockage, transportation, zipping of foramen
  
  • Debris extrusion with a filing motion
  • Time consuming
    Less predictable shapes in curved canals

Question 13

what are characteristic of niti files

Answer 13

• Superelasticity
  
  • Can be strained more than other alloys without permanent deformation
  • Allows niti files to be placed in curved canals with less lateral forces
  • Less transportation, zipping and ledging
    More centrally placed preparation in harmony with the original canal

Question 14

what is the composite of metallurgy niti

Answer 14

Question 15

why can inherit memory in niti files be a problem in curved canals

Answer 15

over instrumentation
canal straightening
unfavourable stress- cyclic fatigue failure

Question 16

what is superplastic wire

Answer 16

Question 17

what is M wire

Answer 17

3 crystalline phase:
- deformed and micro twinned martensite
- premartensitic R phase
- austenite

Question 18

what are the advantages to M wire

Answer 18

Greater flexibility, increases safety
more resistant to cyclic fatigue, improved by almost 400%

Question 19

how is proglider used

Answer 19

Question 20

what are controlled memory files

Answer 20

Question 21

what are advantages to niti vs ss

Answer 21

• Increased flexibility in larger sizes and tapers
  
  • Increased cutting efficiency
  • Better safety in use
    Better user friendliness with less instruments and simple sequences

Question 22

what are the advantages to a target taper in niti files

Answer 22

Question 23

what are disadvantages to niti files

Answer 23

• Instrument fracture
  
  • Expense
  • Access can be difficult in posterior teeth
  • Unsuitable for complex canal anatomy

Question 24

what are the aims of inter-appointment dressings

Answer 24

To reduce and prevent multiplication of micro-organisms that remain following careful cleaning and shaping
Prevent reinfection through coronal or apical leakage
Biomechanical prep removed cultivable bacteria in 50% to 80% of cases

Question 25

what is apexification

Answer 25

The process of creating an environment within the root canal and periapical tissue after pulp death that allows a calcified barrier to form across the open apex of an immature root Barrier: Osteocementum or other bone-like tissue

Question 26

what are horizontal root fractures

Answer 26

- Canal at the level of the fracture line is comparable to the apical foramen of an immature tooth - Repair should be similar to apexification and create a barrier that allows coronal portion to be obturated - Frequency of healing (86%) - Now MTA is used

Question 27

what are indications for apexification

Answer 27

- Vital radicular pulp in an immature tooth pulptomy - If vital inflammed pulp is present apically some continued root formation may be expected from surviving hertiwig epithelial root sheath (apexogensis) Pulpless immature tooth with or without periapical radiolucency (MTA is now used)

Question 28

what can be done to manage iatrogenic perforations

Answer 28

Iatrogenic perforations - CaOh can be used to induce hard tissue for: ○ Small perforations ○ Lie within the crestal bone ○ Do not communicate with the oral cavity

Question 29

how can external resorption occur

Answer 29

Mineralised tissues are normally protected by predentine and odontoblasts in the root canal by precementum and cementoblasts on the root surface If predentine/precementum becomes mineralised, or it precementum is mechanically damage multinucleated cells colonise and resorption occurs CaOh can help reduce osteoclastic activity and stimulate repair

Question 30

what is internal resorption

Answer 30

Question 31

what is the tx for internal resporption

Answer 31

if not perforated- exrtripate pulp, dress CaOH, obturate with warm GP if perforated- defect must be sealed, surgically if accessible or intracanal using MTA

Question 32

what are the different types of external resorption

Answer 32

Question 33

what is the MTA method for making an apical barrier

Answer 33

Question 34

what is revascularisation

Answer 34

a. Used in the absence of infection and the presence of suitable scaffold within the root canal ingrowth of tissue from the periapical region, leads to revascularisation of the reticular pulp As root develop continues the dentinal walls thicken and the apex closes

Question 35

how do you do revascularisation

Answer 35

Question 36

what are the phases in GP

Answer 36

Question 37

what are disadvantages

Answer 37

- Lack of adhesion to dentine - When heated, shrinkage on cooling Cannot be heat sterilised- place cones in sodium hypochlorite for 1 minute

Question 38

what are the desired principles of sealer

Answer 38

Question 39

what are different types of sealer

Answer 39

Question 40

what are the properties of bioceramtic sealers

Answer 40

Question 41

what are calcium silicates

Answer 41

Question 42

what are calcium silicates used for in endo

Answer 42

Question 43

what aer the features of MTA

Answer 43

Question 44

what are the features of biodentine

Answer 44