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Endodontic Materials Flashcards

(53 cards)

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1
Q

What are the Endodontic Material Categories?

A
  • Instruments
  • Irrigants
  • Intra-canal medicaments
  • Obturation materials
  • Sealers
  • Pulp Capping materials
  • Root-end filling materials
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2
Q

What are the endodontic instruments used for?

A
  • For mechanical phase of chemo mechanical disinfection
  • Metal files used to remove soft and hard tissues
  • Removes micro-organisms
  • Creates spaces for disinfectants/ medicaments
  • Creates appropriate shape for obturation
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3
Q

What is Stress?

A
  • Deforming force measured across a given area
  • Tensile/compressive/shear/torsional

Stress = Force/ Area

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4
Q

What is the stress concentration point in regard to endodontic instrument?

A
  • Abrupt changes in the geometric shape of a file that leads to a higher stress at that point
  • Can be due to notch and change in file shape
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5
Q

What is Strain?

A
  • Response of a material to stress
  • Amount of deformation a file undergoes
    Strain = Delta L / L
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6
Q

What is Elastic Limit in regard to metal file?

A
  • A set value representing the maximal strain that when applied to a file, allows the file to return to original dimensions
  • File still has fracture point if stress vs strain too much
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7
Q

What is elastic deformation?

A
  • Reversible deformation that does not exceed elastic limit
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8
Q

What is plastic deformation?

A
  • Permanent bond displacement occurring when elastic limit exceeded
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9
Q

What is the Plastic Limit?

A
  • Point at which a plastic deformed file breaks
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10
Q

2 types of fatigue

A
  • cyclic
  • torsional
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11
Q

What is Cyclic Fatigue?

A
  • File is freely rotating in a curvature
  • Generation of tensions/ compression cycles
  • Leads to cyclic fatigue and eventually failure
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12
Q

What is Torsional fatigue?

A
  • file end is binded / locked
  • while the other end rotating
  • torsional/ twisting force
  • plastic deformation and failure
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13
Q

What is stainless steel for the Kfiles made of?

hand files

A
  • Alloy of iron, carbon and chromium
  • Nickel may also be present
  • Improved carbon steel – rusting
  • 13-26% chromium prevents rusting
  • Passivation layer of chromium oxide
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14
Q

How are kfiles manufactured?

A
  • Machined stainless steel wire
  • Square/ Triangular
  • Twisted
  • Work hardening occurs
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15
Q

What is the process of Work hardening?

A
  • Strengthening of a metal by plastic deformation
  • Crystal structure dislocation occurs
  • Dislocations interact and create obstructions in crystal lattice
  • Resistance to further dislocation formation develops
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16
Q

What is Nitinol?

A
  • Equiatomic alloy of nickel and titanium
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17
Q

What are the properties of Nitinol?

A

Exotic metal - Does not conform to typical rules of mettalurgy
Super-elasticity - Application of stress does not result in usual proportional strain

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18
Q

What is shape memory?

A
  • Alloys are materials that can be deformed at one temperature but when heated or cooled, return to their original shape.
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19
Q

What is the shape memory of KFile?

A
  • Martensitic Phase: At or below room temp the instrument is very malleable and has relaxed serpentine shape
  • Austenitic Phase: Warmer temp (>95degreesF), the instrument transitions to a more robust serpentine shape
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20
Q

What are the properties /use of Irrigant?

A

Plays central role for endo treatment

  • Facilitate removal of debris
  • Lubrication
  • Dissolve of organic and inorganic matter
  • Penetration to canal periphery
  • Kill bacteria/yeasts/viruses
  • Biofilm disruption
  • Biological compatibility
  • Does not weaken tooth structure
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21
Q

Sodium Hypochlorite
- conc
- main properties
- use
- amount per canal

A
  • 3%
  • dissolve organic material, bactericidal
  • disinfection
  • 30 ml for 10 min prior obturation
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22
Q

EDTA

  • conc
  • main properties
  • use
  • amount per canal
Study These Flashcards
A
  • 17%
  • remove smear layer
  • penultimate rinse for 1 min
  • 3 ml
23
Q

Chlorhexidine digluconate

  • conc
  • main properties
  • use
  • amount per canal
Study These Flashcards
A
  • 0.2%
  • check dam intgrity, disinfect tooth surface

or

  • 2%
  • antimicrobial
  • suspect iatrogenic damage
  • only when NaOCl is contraindicated
24
Q

Sterile saline

  • use
Study These Flashcards
A
  • wash out canal hypochlorite accident suspected
25
Why is Sodium Hypochlorite (NaOCl) used for Irrigant?
- NaOCl ionises in water into NA+ and the hypochlorite ion, OCl- - Establishes equilibrium with hypochlorous acid (HOCl) - Acid/Neutral HOCl predominates - pH 9 and above OCl- predominates - HOCl is responsible for **antibacterial activity**
26
Factors important for NaOCl function
- volume - concentration - contact - mechanical agitation - exchange of ions
27
Preparation of the canal can lead to
- **Smear layer** formed during preparation - Organic pulpal material and inorganic dentinal debris - Superficial 1-5µm with packing into tubules - Bacterial contamination, substrate and interferes with **disinfection** - Prevents **sealer penetration**
28
How do you remove Smear Layer?
- 17% EDTA - 10% Citric Acid - MTAD (Mixture of a Tetracycline isomer, an Acid, and a Detergent - Sonic and Ultrasonic irrigation - Watch apical control!
29
what should you not mix in the canal
EDTA & NaOCl NAOCl and CHX
30
what happen if you mix NaOCl and CHX
- forms para-chloroaniline - cytotoxic and carcinogenic
31
What are the properties of an Ideal Obturation material?
- Easily manipulated with **ample working time** - Dimensionally by tissue fluids stable - Seals the canal laterally and apically - **Non-irritatant** - Impervious to moisture - **Unaffected by tissue fluids** - Inhibits bacterial growth - **Radiopaque** - Does not **discolour** tooth - Sterile - Easily **removed** if necessary
32
What are Gutta-Percha cones made of?
- 20% **Gutta-percha** - 65% **Zinc Oxide** - 10% Radiopacifiers - 5% Plasticizers - Standardised, non-standardised and size-matched
33
What are the functions of Sealers?
- **Seals** space between dentinal wall and core to create a **homogenous seal** - **Fills voids** and irregularities in canal, lateral canals and between gutta-percha points used in lateral condensation - **Lubricates** during obturation - antimicrobial - haematic seal
34
What are the properties of an Ideal Sealer?
- Exhibits **tackiness** to provide good adhesion - Establishes a hermetic seal - **Radiopacity** - Easily mixed - **No shrinkage** on setting - Non-staining - Bacteriostatic or does not encourage growth - **Slow set** - Insoluble in tissue fluids - Tissue tolerant - **Soluble on retreatment**
35
What are the benefits of Zinc oxide and Eugenol as sealer?
- Radio-opacity < GP - Rosin or Canada Balsam added to increase **dentine adhesion** - can be added with **corticosteroid** - anti-inflammatory - Zinc oxide effective **antimicrobial** and is **cytoprotective**
36
disadvnatages of ZOE
- free eugenol remained can be **irritant** - lose volume with time due to **dissolution**
37
Positive and negative of glass ionomer sealer?
- Advocated due to **dentine bonding properties** - **Removal** upon retreatment is difficult - **Minimal antimicrobial** activity
38
Positive and negative of **epoxy resin** sealer? | AH plus
- antimicrobial - haematic seal - Slow setting - 8 hours - Good sealing ability - Good flow - Initial toxiicity declining after 24 hours
39
What is **EndoRez**? Give positives
- UDMA resin-based sealer - **Hydrophilic** - **Good penetration into tubules** - **Biocompatible** - Good **radio-opacity**
40
What is Epiphany?
- dual cure - dental resin composite sealer - requires self-etch primer
41
What are some properties of **Calcium Silicate Sealers**? | Bio Ceramic
- High pH (12.8) during the initial 24 hours of the setting - **Hydrophilic** - Enhanced **biocompatibility** - **Does not shrink** on setting - Non-resorbable - Excellent sealing ability - Quick set - three to four hours – requires moisture - **Easy to use**
42
What sealers are not acceptable?
- Sealers containing **Paraformaldehyde** - Severe and permanent **toxic** effects on periradicular tissues
43
What are the two colours of mineral trioxide aggregate? | MTA
- Grey - White
44
What is an example of MTA?
Tricalcium silicate Dicalcium silicate
45
setting rx of MTA
- required water - extended setting times - for open apex, can draw moisture from apex - can't be used in oral cavity (long setting time)
46
advantages of MTA
- Stimulate tissue **regeneration** of dentin and bone - **Biocompatibility** - Excellent **Sealing** Ability
47
components of MTA
* tricalcium silicate, * dicalcium silicate, * tricalcium aluminate, * calcium sulfate, * and a small amount of bismuth oxide
48
use of MTA
* Root Canal Repair: * Pulp Capping: * Apexification: * Root End Filling: *
49
Biodentine use | calcium silicate cement
- root perforation/ pulp floor - internal & external resorption - apexification - retrograde root canal obturation - direct/ indirect pulp capping - pulpotomy - temporary sealing of cavities - cervical filling
50
Direct pulp capping material
- Dycal ( setting CaOH) - Biodentine
51
advantages of Dycal as direct pulp cap material
- stimulate formation of **reparative** **dentine** (direct contact of pulp) - promote **odontoblast differentiation** - forming a **dentine bridge** - induce proliferation of pulp fibroblast
52
disadvantages of Dycal as direct pulp cap material
- poor bonding to dentine - mechanical instability - continued resorption after placement (microleakage)
53
example of core build-up
- para core - SDR (composite core)

Endodontics (7 decks)

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