Endo Flashcards

1
Q

2 types of fibres which transmit dental pain & sensations they trigger

A

A delta fibres → sharp, shooting pain
C fibres → dull, aching pain

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2
Q

Special investigations for endodontic examination

A
  • Percussion
  • Palpation
  • Mobility
  • 6PPC of tooth
  • Sensibility: EPT, cold
  • Radiographs
  • Frac finder/ tooth sleuth
  • Test cavity
  • Selective anaesthesia
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3
Q

Which nerves do EPT typically stimulate?

A

A-delta
C fibres may not respond

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4
Q

In what cases may EPT readings be unreliable?

A

Open apices
Recent trauma

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5
Q

2 diagnoses in AAE endodontic diagnosis

A

Pulpal diagnosis
Periapical diagnosis

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6
Q

AAE pulpal diagnoses (7)

A
  • Normal pulp
  • Reversible pulpitis
  • Symptomatic irreversible pulpitis
  • Asymptomatic irreversible pulpitis
  • Pulpal necrosis
  • Previously treated
  • Previously initiated treatment
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7
Q

AAE apical diagnoses (6)

A
  • Normal apical tissues
  • Symptomatic apical periodontitis
  • Asymptomatic apical periodontitis
  • Acute apical abscess
  • Chronic apical abscess
  • Condensing osteitis
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8
Q

Contraindications to endodontic treatment

A

Myocardial infarction within last 6 months

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9
Q

Considerations for patients with CVD to undergo RCT (3)

A
  • Stress reduction protocol:
  • Short appointments
  • Sedation
  • Pain & anxiety control
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10
Q

Considerations for diabetic patients to undergo RCT

A

Schedule appt so that does not interfere with patients normal insulin & meal schedule

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11
Q

2 guides for assessing case difficulty and the need for referral for endodontic treatment

A

AAE endodontic case difficulty assessment form

NHS Restorative Dentistry Index of Treatment need - Complexity Assessment

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12
Q

Discussion points to cover when consenting patient to endodontic therapy

A
  • Procedure
  • Prognosis
    Irreversible pulpitis: 90%
    Pulpal necrosis: 80%
  • Alternatives to tx
    No treatment
    Wait for more definitive symptoms to develop
    XLA
  • Risks of tx:
    Perforation
    Instrument separation
    Damage to adjacent restorations
    Missed canals
    Increased risk of fracture
    Failure of endodontic tx
  • Risks of no tx:
    Pain
    Infection
    Swelling
    Loss of teeth
    Infection to other areas
  • Consent
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13
Q

When may sensibility tests yield false positives?

A

Pulp not totally necrotic
Multirooted teeth (pulp in some canals may still be vital)

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14
Q

3 advantages of CaOH as cavity base/ liners

A
  • High pH & stimulates reparative dentine formation
  • Stimulates recalcification of demineralised dentine
  • Neutralises low pH of acidic restorative material
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15
Q

3 disadvantages of CaOH as cavity base/ liners

A
  • Cytotoxic
  • Weak cement
  • Very soluble if not protected
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16
Q

3 design objectives of mechanical preparation

A

Continuous taper
Maintain original location of apical foramen
Keep apical opening as small as possible

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17
Q

Ideal properties of endodontic disinfection irrigants (14)

A
  • Low cost
  • Washing action
  • Reduces friction
  • Kills planktonic microbes
  • Kills biofilm microbes
  • Non toxic to periapical tissue
  • Non-allergenic
  • Enhances cutting of dentine by instruments
  • Temperature control
  • Dissolves organic & inorganic matter
  • Penetrates root canal system
  • Does not weaken dentin
  • Does not react with negative consequences with other dental materials
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18
Q

4 advantages of NaOCl as endodontic disinfection irrigant

A
  • Potent antimicrobial
  • Dissolves pulp remnants & collagen
  • Dissolves necrotic & vital tissue
  • Disrupts smear layer by acting on organic component
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19
Q

Factors important for NaOCl function (5)

A

Concentration (0.5% - 6%)
Volume (30ml after instrumentation, final rinse)
Contact (adequate apical preparation + needle size & type)
Exchange
Mechanical agitation (endoactivator, manual dynamic irrigation)

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20
Q

Concentration of NaOCl used for endodontics

A

0.5% - 6%

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21
Q

3 limitations/ disadvantages of NaOCl

A

Affects dentine properties: elasticity, flexural strength
Unable to remove smear layer by itself
Effect on organic material

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22
Q

Advantage of EDTA (1)

A

Capable of removing smear layer when used with NaOCl

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23
Q

Complications of NaOCl use (4)

A

Discolours fabric
Eye injury (chemical burns)
Extrusion injuries
Allergic reactions

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24
Q

MOA of CHX (3)

A

Antiseptic
+ charged CHX attracted to - charged phospholipid molecules

Binds to cell wall and causes it to rupture

Cell cytoplasm leaks → lysis → cell death

antiplaque
adsorbs to pellicle, provides bacteriostatic effect lasting 12-14 hours

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25
Q

3 advantages of CHX as irrigant solution

A
  • Antibacterial
  • Antimicrobial substantivity - adsorption prevents microbial colonisation
  • Biocompatible
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26
Q

Disadvantage of CHX

A

Sensitivity possible - anaphylaxis

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27
Q

Interaction between CHX & NaOCl
- What does it form
- Problems it causes

A

Para-chloroaniline

Forms precipitate which may be cytotoxic & carcinogenic

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28
Q

Proposed cleaning & shaping protocol

A
  • 3% NaOCl irrigation throughout instrumentation
  • 30ml NaOCl penultimate rinse after instrumentation complete with MDI for 10 mins prior to obturation
  • 1 min EDTA rinse
  • Final NaOCl rinse
  • Dry with paper points between irrigants
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29
Q

Symptoms of NaOCl extrusion (6)

A
  • Pain
  • Swelling
  • Ecchymosis
  • Haemorrhage
  • Bad smell/ taste if bleach extrudes into maxillary antrum
  • Intraoral ulceration
  • Intraoral necrosis
  • Airway obstruction
  • Neurovascular deficit
  • Altered sensation in areas of supply by mental nerve & infraorbital nerve
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30
Q

Risk factors of NaOCl extrusion

A
  • Excessive pressure during irrigation
  • Needle locked in canal
  • Loss of control of working length
  • Large apical diameters
    – Root resorption
    – Immature teeth
    – Developmental abnormalities
  • Roots of maxillary molars close to sinus
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31
Q

Management of NaOCl extrusion (10)

A
  • Stop tx
  • Reassure pt and explain what’s happened + management
  • Provide LA
  • Irrigate with saline
  • Allow haemostasis if profuse bleeding
  • Dress with odontopaste
  • Temporise and seal access cavity
  • Post op advice
    – Analgesia (Paracetamol +/- ibuprofen)
    – Cold compress initially to reduce swelling
    – Warm compress after to reduce ecchymosis
  • Refer if severe
  • RV in 24 hours
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32
Q

How to prevent NaOCl accidents (12)

A
  • Pre-op assessment for apices, perforations
  • Good isolation: pre-endo build up if needed, caulking agent (opaldam), check seal of dam, dam approved by clinician
  • Use index finger to depress plunger
  • Luer lock syringe
  • Fill syringe less for better control
  • Side vented needle
  • Needle should not bind
  • Use rubber stopper on needle 2mm short of WL
  • Bib and glasses for patients
  • Pass syringe behind patient
  • Report irrigation/ endodontic incident to staff
  • Report any concern about clinical handling of NaOCl
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33
Q

Contents of odontopaste (4)

A
  • ZOE
  • Triamcinolone acetonide (corticosteroid)
  • Clindamycin hydrochloride (antibiotic)
  • CaOH
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34
Q

Use of odontopaste (1)

A

To reduce inflammation in inflamed +/ hyperaemic pulps to be root treated

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35
Q

Contents of ledermix (2)

A
  • Demeclocycline (tetracycline antibiotic)
  • Triamcinolone acetonide (corticosteroid)
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36
Q

Uses of ledermix

A

To reduce inflammation in inflamed +/ hyperaemic pulps to be root treated

37
Q

3 advantages of non setting CaOH

A
  • High pH, antibacterial (hydrolysis of LPS reducing its inflammatory potential)
  • Removes tissue debris
  • Improves cleaning ability with NaOCl
38
Q

3 types of inter-appointment temporary dressings in endodontics

A
  • GI
  • Coltosol
  • Cavit
39
Q

Difference between K-reamers, K-files and H-files

A
  • Cross section
    K files (square), K reamers (triangle), H files (comma shaped)
  • Method of use
  • Purpose
40
Q

What motion are Hedstrom files used with?

A

Filing motion

40
Q

Uses of Hedstrom files

A

GP removal
Fractured instrument removal in retreatment cases

41
Q

What motion are K-reamers used with?

A

Winding (¼ to ½ turn CW)

42
Q

Advantages of NiTi material as endodontic file (2)

A
  • Superelasticity
    – Less transportation, zipping & ledging
    – Maintains original canal shape
43
Q

Advantages of NiTi over SS files

A

More flexible
More efficient cutting
Safe
User friendly

44
Q

Disadvantages of NiTi files

A
  • Expensive
  • Access difficult posteriorly
  • Unsuitable for complex canal anatomy
  • Instrument fracture
45
Q

How to select which Reciproc files to use (R25, R40 or R50)

A

R25 if canal partially/ completely invisible on pre-op radiograph // if visible on radiograph but size 20 file cannot go to WL passively

R40 If visible on radiograph but size 20 file can go passively to WL

R50 if size 30 file can go passively to WL

46
Q

2 causes of instrument separation

A

Torsional fatigue (incorrect file size, locked tip)
Cyclic fatigue (repeated use of file)

47
Q

Constituents of GP (4)

A

Gutta percha 20%
Zinc oxide 65%
Radio opacifiers 10%
Plasticizers 5%

48
Q

GP obturation techniques

A

Cold lateral compaction
Size matched cones
Warm vertical compaction
Continuous wave obturation
Carrier based obturation

49
Q

Functions of sealer (3)

A

Seals space between core material and dentinal wall

Fills voids and irregularities in canals, lateral canals and between GP in lateral condensation

Lubricates during obturation

50
Q

Properties of an ideal sealer

A
  • Tacky to provide good adhesion
  • Establishes hermetic seal
  • Easily mixed
  • Slow set
  • No shrinkage on setting
  • Non staining
  • Bacteriostatic
  • Insoluble in tissue fluids
  • Tissue tolerant
  • Soluble on retreatment
51
Q

4 types of sealers

A

ZOE based sealants
GI sealants
Resin based sealants
Calcium silicate sealants

52
Q

Advantages (1) and disadvantages (2) of ZOE based sealer

A

Advantage: antimicrobial
Disadvantages
Free eugenol - irritant
Loses volume with time

53
Q

Advantages (1) and disadvantages of GI sealers (2)

A

Advantage: good dentine bonding

Disadvantage:
Minimal microbial activity
Difficult to retrieve

54
Q

Advantages of resin sealers (3)

A

Good seal
Good flow
Slow setting

55
Q

Advantages of calcium silicate sealers (6) and 1 disadvantage

A

Advantage
- Hydrophilic
- Biocompatible
- Does not shrink on setting
- Non resorbable
- Good seal
- Quick set
- Easy to use

Disadvantage
- Difficult to retrieve

56
Q

Criteria for successful outcome post endo (according to ESE guidelines)

A

At 1 year assessment:
- Absence of pain, swelling, sinus tracts and other symptoms of inflammation
- No loss of function
- No radiographic signs of PA pathology

57
Q

Criteria for uncertain outcome post endo (according to ESE guidelines)

A

Initial radiographic lesion remains same size, or slightly reduced in size

58
Q

Criteria for unfavourable outcome post endo (according to ESE guidelines)

A

Signs & symptoms of infection
- New lesion appeared post tx/ pre existing lesion increased in size
- Pre-existing lesion remained same size/ reduced in size 5 years post endo
- Continuing root resorption

59
Q

4 pre-op factors affecting endodontic success

A
  • Presence (absence) of pre-op lesion
  • Filling to within 2 mm of radiographic apex but not extruded
  • Well condensed fillings with no voids
  • Quality coronal restoration
60
Q

3 laws of access & canal location (3 + 3)

A
  1. Law of symmetry I & II:
    - Orifice of canals are equidistant from (I) & perpendicular to (II) a line drawn in a MD direction through pulp chamber floor
  2. Law of colour change
    Pulp chamber floor is darker than pulpal walls
  3. Law of orifice location I, II & III
    Orifice of canals located at junction of the floor & walls (I), and at its angles(II), and at the terminus of the developmental fusion lines (III)
61
Q

Reasons for endodontic failure (8)

A
  • Missed canals
  • Perforation
  • Instrument separation
  • Root fracture
  • Ledges
  • Radicular cysts
  • Faults in obturation: not to length (2mm of radiographic apex), extruded sealant, poorly condensed filling with voids
  • Coronal leakage
62
Q

Rotary file systems suitable for retreatment

A

Protaper D1 - D3
Reciproc

63
Q

What file can be used to bypass ledges?

A

Pre-curved C+ file

64
Q

5 complications of endodontic instrumentation

A
  • Perforation
  • Ledging
  • Zipping
  • Apical transportation
  • Fractured instrument
65
Q

How to avoid perforation

A
  • Good pre-op assessment & planning: radiographs
  • Good knowledge of anatomy
  • Measure pre-op radiograph to pulp chamber roof/ floor
  • Use DG16 and rubber stopper as depth gauge
66
Q

How to avoid zipping/ transportation (3)

A
  • Pre curving initial small hand instruments for curved canals
  • Do not skip instruments in sequence
  • Do not rotate instruments in curved canals
67
Q

How to avoid short obturation

A
  • Good pre-op assessment: EWL
  • Apical gauging
  • Reference point selection
  • Cone fit radiograph
68
Q

How to avoid blockages

A
  • Don’t skip files
  • Ensure file is passive before moving onto a bigger file
  • Don’t force files
  • Copious irrigation and recapitulation
  • Reservoir of irrigant in pulp chamber while instrumenting
69
Q

How to avoid fractured files

A
  • Aware of limitations of instrument
  • Use recognised technique
  • Pay attention to degrees of rotation
  • Stay focused
  • Lubricate canal
  • Know settings of rotary
70
Q

How to avoid loss of control during obturation

A
  • Obturate one at a time
  • Super endo alpha to remove excess
  • Buchanan plugger to condense
  • Magnification
71
Q

Anterior restoration option for anterior teeth with intact marginal ridges

A

Composite

72
Q

Anterior restoration option for anterior discoloured teeth with intact marginal ridges

A

Bleaching + composite
Veneer

73
Q

Anterior restoration option for anterior teeth with marginal ridges destroyed

A

Core build up with crown
Post core + crown

74
Q

Type of teeth unsuitable for post placement (think anatomy of teeth)

A
  • Mandibular incisors
  • Curved canals
  • Incisors & canines if sufficient coronal dentine
  • Premolars (if needed consider placing in widest root canals)
75
Q

Post design:

  • Minimum post length : crown length ratio
  • Length of post into root
  • Maximum width
  • Remaining root filling length
A

1 : 1

Half of post length into root

No more than ⅓ of root diameter at narrowest point & 1mm of remaining circumferential coronal dentine

4-5mm of apical GP

76
Q

What is a ferrule and why is it important? Minimum height and width of ferrule

A

Collar of sound dentine within the walls of a crown

To prevent tooth fracture

1-2 mm vertical axial tooth structure

77
Q

3 ideal post designs and why (3 + 4)

A

Parallel (no wedging effect + retentive)

Non threaded (passive - incorporates less stress to remaining tooth)

Cement retained (buffer between masticatory forces and post/ tooth)

78
Q

3 post materials

A

Metal
Ceramic
Fibre

79
Q

Advantages (1) & disadvantages (5) of metal posts

A

Advantages:
High strength

Disadvantages:
- Poor aesthetics
- Root fractures
- Corrosion
- Nickel sensitivity
- Radiopaque on radiographs

80
Q

Advantages (3) and disadvantages (2) of ceramic posts

A

Advantages:
Aesthetic
High flexural strength
High fracture toughness

Disadvantages:
Difficult to retrieve
Root fracture common

81
Q

Advantages (5) of fibre posts

A

Aesthetic
Retrievable
Flexible
Bonds to dentine with DBA
Radiolucent on radiographs

82
Q

Recommended use for tapered & parallel prefabricated posts

A

Circular, small canals

83
Q

Recommended use for custom cast post & core

A

Elliptical or flared canals

84
Q

4 important bits of information to include in a cast post & core prescription to the lab

A

Size of preparation (para post colour)
Core 6 degree taper
Amount occlusal clearance needed for crown
Shade

85
Q

4 complications of post placement

A

Perforation
Core fracture
Root fracture
Post fracture

86
Q

3 indications for non surgical root canal treatment

A
  • New complex restoration with technically poor endo
  • Failed endodontic treatment: inflammation, symptomatic, PA pathology
  • Loss of coronal seal
87
Q
A