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COPY BDS3 University of Adelaide Dentistry > Endodontics > Flashcards

Endodontics Flashcards

1
Q

What are 3 options for Vital Pulp Therapy?

A

Direct Pulp Capping
Partial Pulpotomy
Full Pulpotomy

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2
Q

What is the max threshold for EPT testing?

A

80

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3
Q

What could give false positives/negatives for EPT testing

A

Saliva
Metal conduction on Amalgams
Coronal Calcification
Only one root of multirooted tooth is affected

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4
Q

What are 3 non-toxic capping materials that can be used for indirect pulp capping?

A

Calcium Hydroxide (Life)
Mineral Trioxide Aggregate (MTA)
Biodentine

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5
Q

Why is MTA a better capping material CaOH?

A

Less tunnel defects for the calcific bridge

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6
Q

What are the clinical signs of Ludwig’s Angina?

A

Airway Obstruction
Protrusion of tongue
Spread of exudate within fascial spaces
Oedema, Inflammation of soft tissues below the jaw

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7
Q

An extra-oral sinus tract is known as what?

A

A fistula

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8
Q

What is the limitation of antibiotics in managing apical abscesses?

A

Antibiotics can’t access the necrotic pulp

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9
Q

If a patient is allergic to penicillin, what is the first line AB to use to manage a apical abscess?

A

Clindamycin 300mg every 8 hours for 5 days

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10
Q

What is the name for the condition where there is chronic tooth pain with no obvious aetiology

A

Atypical Odontalgia

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11
Q

T/F: Endodontic lesions can be aerobic in nature

A

False: they are either facultative or anaerobic in nature

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12
Q

What are 5 ways bacteria can cause an endodontic lesion?

A
  1. Caries including microleakage
  2. Mechanical Exposure
  3. Trauma
  4. Anachoresis: infection via bloodstream bacteremia
  5. Periodontal Pocket (Endo/Perio lesion)
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13
Q

Where can endodontic bacteria be located in the tooth?

A
  1. Root Canal
  2. Lateral/Accessory Canals: RCT can often miss these channels
  3. Dentine Tubules: microbes can hide here
  4. Extra-radicular space (outside on the root)
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14
Q

During a chronic endodontic infection, does the environment become less or more favourable to obligate anaerobes?

A

More favourable to obligate anaerobes via autogenic means - oxygen is consumed by facultatives and then the drop in redox potential sets the environment for obligate anaerobes.

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15
Q

Endodontic microbial interactions with each other can exist via two mechanisms. What are these?

A
  1. Antagonistic - competition for nutrients, production of toxic metabolites and bacteriocins
  2. Synergistic - proteolytic degradation provides nutrients for other species
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16
Q

What are the two ways to remove endodontic agents

A
  1. Mechanical removal - RCT. This alters the redox potential by adding more oxygen into the environment
  2. Chemical medicaments to sterilise/disinfect the environment
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17
Q

What are chemical medicaments that can sterilise/disinfect an endodontically treated tooth?

A
  • Sodium Hypochlorite (Miltons)
  • Calcium Hydroxide
  • Ledermix
  • EDTA (Chelating agent to metal ions - microbes can’t use)
  • CHx
  • Peroxides
  • Camphorated Monochlorophenol (CMCP)
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18
Q

What can prevent the effectiveness of chemical medicaments for endo treated teeth?

A
  1. Operator Technique

2. Inability to access lateral/accessory canals

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19
Q

What are some possible reasons for endodontic failure?

A
  1. Inadequate treatment or re-infection of the root canal
  2. Possibly Resistant Species (eg Enterococcus Faecalis)
  3. Reinfection from extraradicular lesions (from outside the root)
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20
Q

When can bacteraemia occur during endodontic treatment?

A

When instruments extend beyond the apical foramen. However the risk of bacteraemia is less than scaling/extractions

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21
Q

What are sources of non-odontogenic pain?

A

TMD
Trigeminal Neuralgia
Sinus Pain

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22
Q

What are the 2 main components of endodontic diagnosis?

A
  1. Pulp + Root Canal condition

2. Periapical Status

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23
Q

What are the 4 issues to consider for endodontic treatment?

A
  1. Strategic value of the tooth
  2. Periodontal Factors
  3. Patient Factors
  4. Restorability Options
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24
Q

What are 3 factors that would determine the strategic value of the tooth for endo therapy

A
  1. Aesthetics: 5-5 aesthetic zone
  2. Function: abutment tooth for pros
  3. Occlusion: masticatory value
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25
Q

What clinical perio factors would impact the ability to endodontically treat a tooth?

A
  1. Local/generalised periodontitis
  2. Endo-perio lesions: very poor prognosis
  3. Vertical root fractures: extract
  4. Perforation
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26
Q

What are 4 patient factors that would impact the ability to endodontically treat a tooth?

A
  1. Motivation to retain teeth
  2. Medical History
  3. Age
  4. Compliance with current/future treatment
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27
Q

What are 4 restorability factors that would impact the ability to endodontically treat a tooth?

A
  1. Consider the whole mouth - is caries / perio disease under control?
  2. Limited Supra-gingival tooth structure for restoration
  3. Compromised Teeth: cracked cusps
  4. Restorative Options (Extraction, Fixed, Removable Pros)
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28
Q

What patient considerations are important in determining difficulty of endodontic treatment?

A
  1. Medical History
  2. Anesthesia Issues
  3. Patient Disposition
  4. Ability to Open Mouth
  5. Gag Reflex
  6. Emergency Conditions
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29
Q

What diagnostic and treatment considerations are important in determining difficulty of endodontic treatment?

A
  1. Diagnostic
  2. Radiographic Difficulties
  3. Position in arch
  4. Tooth Isolation
  5. Crown Morphology
  6. Canal + Root Morphology
  7. Radiographic Appearance of canals
  8. Root Resorption
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30
Q

What additional considerations are important in determining difficulty of endodontic treatment?

A
  1. Trauma History
  2. Endodontic Treatment History
  3. Perio-endodontic Condition
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31
Q

What are the layers of the Pulpo-Dentinal Complex?

A 
Dentine
Pre-Dentine
Odontoblast Layer
Cell Free Zone
Cell Rich Zone
Pulp proper (Central Pulp)
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32
Q

What is the issue with the dental pulp being a low compliance environment?

A

High risk of pulpal necrosis, due to compressions of blood vessels with increase in pressure (trauma/infection), since the pulp is surrounded with a rigid encasement that has limited room for expansion

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33
Q

When does tertiary dentine form?

A

In response to low grade chronic trauma

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34
Q

When does primary dentine form?

A

During development of dentition

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35
Q

When does secondary dentine form?

A

Deposition over the lifespan of an individual that decreases pulpal size and tooth sensitivity

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36
Q

T/F: Dentinal Fluid as a inward pressure gradient

A

False

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37
Q

What role does outward flowing pulpal tissue perform?

A

Outward pressure gradient: Fluid moves out when tubules are exposed. In response to exposure the pressure helps to :

1) Protective/Flushing effect if there are bacteria on surface
2) Antigens are diluted on route to the pulp

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38
Q

What trends in terms of dentinal tubule density and diameter would you expect as you got closer to the pulp

A

Density: Increases number of tubules closer to the pulp
Diameter: Higher tubule diameter closer to the pulp

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39
Q

What is the physical properties of Interglobular Dentine?

A

Uneven calcified globules of dentine near to the DEJ that has lower density than globular dentine

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40
Q

What is in the Cell Poor Zone of dental pulp?

A

Capillaries
Unmyelinated nerve fibres

Presence is indicative of health pulp

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41
Q

What is in the Cell Rich Zone of dental pulp?

A

Rich in fibroblasts (reparative ability)

Lymphocytes/Macrophages

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42
Q

What is in the Pre-dentine area of dental pulp?

A

Unmineralised Matrix comprises of

  • Collagen(I, II)
  • PG, GAG, GP?
  • Growth factors
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43
Q

What cells are in the Central Dental Pulp?

A 
Odontoblasts
Fibroblasts
Lymphocytes
Dendritic Cells
Macrophages
Mast Cells
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44
Q

What is the vasculature in the central pulp influenced by?

A
  1. Sympathetic adrenergic vasoconstriction
  2. Neurogenic Pathways (β-adrenergic vasodilation)
  3. Sympathetic cholinergic vasoactive system
  4. Antidromic vasodilation involving sensory fibres

Little evidence of parasympathetic vasodilator mechanism

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45
Q

Where is the cell body of the odontoblast located?

A

At the border of Pre-Dentine

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46
Q

What occurs to the Odontoblastic Process in responseto trauma or caries?

A

Retreats towards the pulp

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47
Q

What can Fibroblasts differentiate into in response to injury?

A

Odontoblastic Precursors

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48
Q

What Lymphocyte is mostly present in healthy dental pulp?

A

T8 Supressor Cells

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49
Q

T/F: Afferent sensory neurons always conduct pain irregardless of stimulus

A

True

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50
Q

What effect does Sympathetic stimulation causes to excitability of Aδ fibres?

A

Vasoconstriction decreases pulpal circulation. This depresses excitability of Aδ fibres

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51
Q

What is the implication of C Fibres resistance to pulp necrosis

A

Possible for patient to still get tooth sensitivity even after a necrotic pulp

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52
Q

Rapid desiccation can do what odontoblasts?

A

the outward flow of fluid aspirates (pulls) the process outwards

If traumatic enough, can break the process off, then needs to be repaired by odontoblasts

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53
Q

Low level chronic trauma to the pulp will result in what to the dentinal tubule?

A

Tubular Sclerosis - fibrotic repair

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54
Q

What are pulp stones?

A

Dystrophic calcification caused by islands of reparative dentine formed during chronic long term trauma

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55
Q

What will be the main immune response to acute pulpal inflammation?

A

PMNs

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56
Q

What will be the main immune response to chronic pulpal inflammation?

A

Monocytes

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57
Q

What cells are involved with a proliferative response to chronic pulpal inflammation

A

Angioblasts

Fibroblasts

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58
Q

What vascular response occurs to pulpal injury

A

Hyperaemia (Vasodilation)

Increased Permeability: exudate of plasma proteins, leukocytes

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59
Q

What are 3 Neuropeptides involved with pulpal pain

A

Calcitonin Gene Related Peptide (CGRP)
Substance P
Neurokinin A

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60
Q

What 3 things do Neuropeptides due in response to pulpal inflammation?

A

Hyperexcitation
Vasodiation
Vascular Leakage

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61
Q

What nerve fibres are involved with dentinal hypersensitivity?

A

Hot/Cold Stimuli > Rapid Movement of Fluid in Dentinal Tubules > Activates Aδ fibres

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62
Q

What nerve fibres are involved with reversible pulpitis?

A

Aδ or C Fibres

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63
Q

What nerve fibres are involved with irreversible pulpitis?

A

C Fibres

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64
Q

What nerve fibres are involved with Necrotic Pulp

A

None, although some lingering C Fibre innervation at the early stages of pulpal death

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65
Q

What is the character of pain from A-Delta fibres?

A

Sharp and Localised

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66
Q

What is the character of pain from A-Delta fibres?

A

Dull Throbbing, Generalised

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67
Q

What are possible sources of acute physical trauma to the pulp?

A

No Bur Water Spray
Physical Trauma to Tooth: dessication
Root Planing
Rotary Polishing

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68
Q

What are possible sources of acute chemical trauma to the pulp?

A

Medicaments on Dentine

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69
Q

What are possible sources of chronic physical trauma to the pulp?

A

Abrasion

Attrition

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70
Q

What are possible sources of chronic bacterial trauma to the pulp?

A

Caries
Cracks
Microleakage

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71
Q

What are the 4 principles of Coronal Endodontic Cavity Preparation?

A

Outline Form
Convenience Form
Removal of Carious Dentine
Cavity Toilet

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72
Q

What is Outline Form for Coronal Endodontic Cavity Preparation?

A

To project the internal anatomy of the tooth to the outside of the tooth.

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73
Q

What is Convenience Form for Coronal Endodontic Cavity Preparation?

A

To allow accurate preparation and filling of root canals:

  1. Unobstructred access to Canal Orifices
  2. Direct Straight Line Access to apical foramen
  3. Complete authority over instruments
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74
Q

What factors can alter Outline Form for Coronal Endodontic Cavity Preparation?

A
  1. Size/Shape of Pulp Chamber
  2. Age
  3. Presence of Restorations
  4. Primary / Secondary Dentition
  5. Pathology (Pulp Stones, Dens Invaginatus)
  6. Secondary/Tertiary Dentine
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75
Q

If on an upper anterior, the cingulum vault is not properly removed, what issues could occur?

A
  1. Excessive bending on files resulting in broken files

2. Difficulty controlling file apically

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76
Q

How many bends can files tolerate?

A

One bend on the apical 1/3rd

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77
Q

What are the 3 aims of removing carious dentine during endodontic treatment?

A
  1. Removal of bacteria from pulp chamber
  2. Removal of unsupported tooth structure
  3. Provision of a sound seal to prevent re-infection
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78
Q

What is the aim of the cavity toilet in Coronal Endodontic Cavity Preparation?

A

Removal of caries/debris and necrotic tissue from the pulp chamber before radicular preparation begins (“sterilisation of the chamber”)

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79
Q

How is a cavity toilet prepared?

A
  1. Slow Speed Tungsten Carbide
  2. Hand Instrumentation
  3. Triplex Air/Water
  4. Chemical Sterilisation with Miltons (1% % sodium hypochlorite (NaClO) and 16.5% sodium chloride (NaCl)
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80
Q

T/F: Access to the pulp for endodontic access on anteriors can be done through worn dentine on the incisal table

A

False, this method is too destructive.

Access should occur through the middle 1/3rd of the tooth

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81
Q

What angle of initial access should be on maxillary anteriors?

A

45 degrees

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82
Q

What angle of initial access should be on mandibular anteriors?

A

90 degrees

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83
Q

How do you locate the second mesial buccal (MB2 ) on a maxillary molar?

A

Draw a line from the MB root to the MP root and it will be slightly mesial of this line

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84
Q

What are the 3 laws that establish clinical patterns and relationships between the Pulp Chamber to Clinical Crown?

A
  1. Law of CEJ: The CEJ is most consistent, repeatable landmark for locating the position of the pulp chamber. Clinically - whilst doing the coronal prep by doing cuff technique so you can continuously visualise the CEJ
  2. Law of centrality: Floor of pulp chamber is always located in the centre of the tooth at the level of the CEJ
  3. Law of concentricity: Walls of the pulp chamber are always concentric to the external surface of the tooth at the level of the CEJ
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85
Q

Which teeth don’t follow Relationships of Pulp Chamber Floor to canals?

A

Maxillary Molars

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86
Q

What are the 4 relationships that exist between the Pulp Chamber Floor to canals?

A
  1. Orifices of the canals are equidistant from a line drawn in a M-D direction through the pulp chamber floor
  2. Orifices of the canals lie on a line perpendicular to a line drawn in a M-D direction across the centre of the floor of the pulp chamber
  3. Orifices of the root canals are always located at the junction of the walls and the floor
  4. Orifices of the root canals are located at the terminus of the root development fusion lines
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87
Q

How many canals exist for Lower 1s?

A

1 Canal 70% of the time

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88
Q

How many canals exist for Lower 2s?

A

1 Canal 50% of the time

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89
Q

How many canals exist for Lower 3s?

A

1 Canal 94% of the time

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90
Q

How many canals exist for Lower 4s?

A

1 Canal 71% of the time

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91
Q

How many canals exist for Lower 5s?

A

1 Canal 86% of the time

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92
Q

How many canals exist for Lower 6s?

A

4 Canal 65% of the time

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93
Q

How many canals exist for Lower 7s?

A

3 Canal 90% of the time

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94
Q

What is the average length of a lower 1?

A

21.5

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95
Q

What is the average length of a lower 2?

A

22.5

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96
Q

What is the average length of a lower 3?

A

25.2

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97
Q

What is the average length of a lower 4?

A

22.1

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98
Q

What is the average length of a lower 5?

A

21.4

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99
Q

What is the average length of a lower 6?

A

21

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100
Q

What is the average length of a lower 7?

A

21

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101
Q

What is the average length of an upper 1?

A

23.3

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102
Q

What is the average length of an upper 2?

A

21.5

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103
Q

What is the average length of an upper 3?

A

26

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104
Q

What is the average length of an upper 4?

A

21.8

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105
Q

What is the average length of an upper 5?

A

21

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106
Q

What is the average length of an upper 6?

A

20

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107
Q

What is the average length of an upper 7?

A

20

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108
Q

How many canals exist for Upper 1s?

A

1 Canal 100% of the time

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109
Q

How many canals exist for Upper 2s?

A

1 Canal 100% of the time

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110
Q

How many canals exist for Upper 3s?

A

1 Canal 100% of the time

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111
Q

How many canals exist for Upper 4s?

A

2 Canals 90% of the time

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112
Q

How many canals exist for Upper 5s?

A

1 Canals 75% of the time

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113
Q

How many canals exist for Upper 6s?

A

3 Canals 40% of the time

4 Canals 60% of the time

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114
Q

How many canals exist for Upper 7s?

A

3 Canals 63% of the time

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115
Q

Which direction do upper 1s curve?

A

75% Straight

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116
Q

Which direction do upper 2s curve?

A

53% Distal

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117
Q

Which direction do upper 3s curve?

A

40% Straight

30% Distal

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118
Q

Which direction do upper 4s curve?

A

50% Palatal

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119
Q

Which direction do upper 5s curve?

A

30% Distal

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120
Q

Which direction do lower 1s curve?

A

60% Straight

25% Distal

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121
Q

Which direction do lower 2s curve?

A

60% Straight

25% Distal

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122
Q

Which direction do lower 3s curve?

A

70% Straight

20% Distal

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123
Q

Which direction do lower 4s curve?

A

50% Straight

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124
Q

Which direction do lower 5s curve?

A

40% Straight

40% Distal

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125
Q

What burs should be used for endodontic coronal preparation?

A
  1. Outline Form:
    High Speed Tapered diamond bur
    High Speed 169L tungsten carbide bur
    Beaver Bur – 1931, 1938
  2. Convenience Form:
    Slow Speed 3/4 shank 3 round tungsten carbide
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126
Q

Where is the apical constriction in relation to the radiographic apex?

A

Usually 0.5-1.0mm short of the Radiographic Apex

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127
Q

What techniques can be used to unobscure multiple roots in a radiograph?

A

20 Degree Tube Shift: SLOB Rule

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128
Q

Which radiographic technique would you use for a PA to overcome anatomical difficulties?

A

Bisecting Angle Technique

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129
Q

What Maxillary Anatomical difficulties could obscure PAs for Endo?

A 
Incisive Foramen
Zygomatic Arch
Maxillary Tori
Flat Palates
Gag Reflexes
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130
Q

What Mandibular Anatomical difficulties could obscure PAs for Endo?

A 
Mental Foramen
Lingual Depression
Lingual Frenum (for pre-molars)
Mylohyoid Muscle
Mandibular Tori
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131
Q

Where should working length be determined?

A

At the apical constriction

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132
Q

How do apex locators work?

A

Connecting a mucous resistive circuit that connects the Endo File to the Apical Foramen and connects to the patient’s lower lip

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133
Q

What are the advantages of apex locators?

A
  1. Accurate determination of working length
  2. Perforations can be detected easily
  3. Working length can be checked with every file
  4. Lower radiation dose: fewer films required
  5. Confidence cleaning and shaping (particularly with rotary endo)
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134
Q

What are the disadvantages of apex locators?

A
  1. Some pacemaker patients are contraindicated (pre 2000)
  2. Accurate measurement cannot always be made:
    Calcified canals +
    Old root filling obstructs canal
  3. Open Apices
  4. False Positives / Negatives
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135
Q

What factors could give false positives for apex locators?

A

Field Too Wet
Vertical Root Fracture
Lateral Canals

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136
Q

What factors could give false negative for apex locators?

A

Calcified Canals
Old Root Filling
Low Battery in Apex Locator

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137
Q

Where would unusual fractures be?

A

Incisors + Pre-Molars - can be indicative of physical trauma: fighting and domestic violence

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138
Q

How reliable are apex locators?

A

75% accuracy at 0.5mm
83% accuracy at 0.75mm
89% accuracy at 1.0mm

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139
Q

What is working length?

A

The distance between:

1) A Coronal Reference Point to
2) The point where the canal preparation and obturation should terminate

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140
Q

What happens to biocompatibility of an irrigant the more effective it becomes?

A

More effective irrigants are less biocompatible

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141
Q

T/F: NaOCl dissolves the inorganic component of dentine?

A

False, it removes organic (vital / necrotic pulp tissue). Chelating agents are used for removing inorganic aspects of dentinal smear layer

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142
Q

In the absence of bacteria, what would happen to a mechanically opened pulp chamber?

A

Dentine would respond to injury and build a dentinal bridge to close the space

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143
Q

If there are no bacteria is present at the point of obturation, what is the success rate of RCT at 4 years?

A

94%

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144
Q

Use of files and saline irrigants would do what to bacterial count nubers

A

Reduction 100-1000x fiold

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145
Q

Is there any difference in clinical efficacy for bacterial removal when comparing NiTi rotary vs stainless steel hand files?

A

No

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146
Q

What is the best combination of irrigant to remove bacterial from canals?

A

File + NaOCl irrigant + CaOH dressing

1 Week: 93% of root canals bacteria free
1 Month: No bacteria recovered

147
Q

What are the 5 objectives of irrigation?

A
  1. Remove microbes
  2. Dissolve and flush organic and inorganic debris
  3. Improve filling efficiency
  4. Lubricate the canal
  5. Non-irritant to healthy tissue
148
Q

What are the 8 properties of an ideal irrigant?

A
  1. Eliminate microorganisms
  2. Low surface tension/good surface wetting (lubricant)
  3. Dissolve organic debris
  4. Flush out inorganic debris
  5. Remove smear layer
  6. Non-toxic
  7. No adverse effects on remaining tooth
  8. Economical
149
Q

Why is NaOCl an effective irrigation agent?

A
  1. Potent antimicrobial agent: kills bacteria instantly on direct contact
  2. Effectively dissolves organic vital and necrotic pulp tissue
150
Q

What are the effective concentrations for NaOCl?

A

0.5% to 5.25%

151
Q

What are the 3 factors for irrigation that ensure success?

A

Correct Volume
Correct Time
Depth of Needle Penetration (requires to be in the apical 1/3rd)

152
Q

When is it more likely to have a NaOCl accident

A
  1. Tooth Factors: Immature Apices, Root Resorption, Perforation: noticeable if the paper point returns bleeding (past the apex)
  2. Excessive Concentration + Pressure when irrigating
153
Q

What are 3 clinical accidents for NaOCl?

A
  1. Bleached clothes from external spray
  2. Local irritation on their gums (insufficient rubber dam and not using oroseal)
  3. Irrigation goes past point of tooth apex
154
Q

What are limitations of NaOCl?

A
  1. Unpleasant taste: need rubber dam
  2. Toxicity to healthy cells
  3. Inability to remove smear layer (only dissolves the organic component)
  4. Require chelating agent to work in combination
  5. Reduced flexural strength
  6. Reduced elastic modulus
  7. Reduced microhardness
155
Q

What agent can remove the inorganic component of dentinal smear layer?

A

Chelating Agents such as

  1. Ethylenediaminetetraacetic acid (EDTA)
  2. EDTAC (EDTA + Quaternary Ammonium)
156
Q

What is the action of EDTA?

A

Smear layer removed by chelating the inorganic component of dentine - exposes tubules

  1. Dentinal tubules widened
  2. Dentine softened, facilitates preparation
  3. Dentine permeability increased - Enhances medicament effectiveness + cement adhesion
157
Q

What are the limitation of Paste Chelating Agents such as RC Prep or Glyde?

A

Carbowax film remains on surface, difficult to remove, can cause

  1. Can clog the flutes of the instrument/file
  2. Increases risk of fractures
158
Q

What are issues of using CHx and NaOCl together as irrigants?

A

Causes a brown precipitate that stains the tooth brown

159
Q

What are the issues of using Iodine irrigant

A
  1. Staining

2. Allergic Reactions

160
Q

What is in MTAD?

A

Tetracycline (doxycycline)
Acid (Citric acid)
Detergent (Tween-80)

161
Q

What are the properties of MTAD?

A

Poor ability to dissolve pulp tissue and organic component of smear layer

162
Q

When can MTAD be used?

A

Initial NaOCl at preparation procedure

Final 5 Minute Rinse with MTAD

163
Q

What is considered gold standard for irrigation?

A
  1. NaOCl during instrumentation to remove organic material
  2. EDTA after instrumentation to remove the inorganic material
  3. Final flushing using NaOCl
164
Q

What are the advantages of rotary instrumentation for irrigation?

A

Increased size and taper of instrumentation allows for more effective irrigant penetration to apical 1/3rd

165
Q

What are consequences of inadequate irrigation?

A
  1. Smear layer remains
  2. Debris remains in canal
  3. Insufficient lubrication
  4. More microorganisms remain
166
Q

Where might NaOCl have poor irrigation performance in the tooth?

A

Apical 1/3rd
Lateral Canals
Isthmuses
Deltas

167
Q

How do you treat a patient if NaOCl irrigation occurs past the tooth apex?

A
  1. Palliation - Patient reassurance, analgesics, anti-inflammatory
  2. Antibiotics if risk of secondary infection
  3. Cold compress in the first 24 hours
  4. Use lower NaOCl concentration and pressure
  5. Have accurate diagnostic information before getting started (OPGs)
168
Q

At what concentrations is Chlorhexidine bacteriocidal and bacteriostatic?

A

Bacteriostatic at low concentrations of 0.2%

Bacteriocidal at high concentrations of 2%

169
Q

How does Chlorhexidine work as an anti-bacterial?

A

Acts by adsorbing onto cell walls of microorganisms: disrupts the integrity of cytoplasmic membranes and causes leakage of intracellular components

170
Q

T/F: Chlorhexidine has tissue-dissolving capacity

A

False

171
Q

How is Chlorhexidine efficacy reduced during irrigation?

A
  1. Due to dentine smear layer

2. Serum Albumin exudate

172
Q

How does Hydrogen Peroxide work as an irrigant?

A

Produces hydroxyl radicals which attack membrane lipids, DNA and other essential cell components

173
Q

What are 2 issues with Hydrogen Peroxide as an irrigant?

A
  1. Highly toxic to tissues

2. No added benefit compared to NaOCl

174
Q

What is Hydrogen Peroxide effect against?

A

Biocide for disinfection: effective against bacteria, viruses, yeasts and spores

175
Q

How can rotary instruments aid in instrumentation?

A

Creation of large canal size and taper allows increased penetration of irrigant, particular in the apical 1/3rd

176
Q

What tool should be used for instrumentation?

A

27 Ga Luer Lock needle

Hypodermic syringe - bent at 45-90 degrees and measured with ruler

177
Q

What techniques need to be employed when irrigating?

A
  1. Needle loose in canal
  2. Use Minimal pressure
  3. Irrigate copiously with high speed suction (During access, During/after initial canal exploration, After each file,
    Final flush)
  4. Aspirate with syringe after
  5. Dry thoroughly with paper points
  6. Extrude slowly with gentle in/out motion
178
Q

What are advantages of single-visit endodontics

A
  1. Decreased treatment time
  2. Better patient acceptance for treatment plan
  3. Decreased cost to the patient
  4. Potentially increased profit for the dentist (can see more patients)
179
Q

What is the main indication for endodontic medicaments?

A

Medicaments guarantee elimination of more bacteria than purely mechanical instrumentation / irrigation alone

180
Q

How are residual bacteria in canals organised?

A

In root canal biofilms

181
Q

What are the implications biofilm adhesion in root canals?

A

Biofilms make bacterial 1000x more times resistant to antimicrobial agents

182
Q

What are the stages of biofilm formation in root canals?

A

Protein Adsorption > Adhesion > Co-adhesion > Detachment

183
Q

What are advantages of medicating in vital cases?

A

1 .Better removal of pulp tissue remnants

  1. Stimulation of hard tissue repair (e.g. open apices)
  2. Reduced post-operative pain
184
Q

Is there a definitive indication for doing single visit endodontics in necrotic infected cases?

A

Still controversial as there are big discrepancies in the literature:

Majority of studies are case series and non-controlled clinical trials with small sample sizes, relative short follow-ups, heterogeneity in clinical protocols and variable operator skill

Animal studies tend to favour CaOH2 medicaments for 2 weeks to single visit endo

185
Q

What 4 criteria should be considered on whether to medicate or not?

A
  1. Biology
  2. Clinical feasibility (time,
    case complexity, patient factors, operator skill,
    Experience)
  3. Evidence (Vital Cases)
  4. Expert opinion (in Australia, mostly multi-visit for infected cases)
186
Q

Why are phenol agents such as CMCP and Formacresol no longer used as medicaments

A
  1. Highly toxic to living tissue

2. Formaldehyde: mutagenic / carcinogenic

187
Q

Which microbes are resistant to CaOH2?

A 
Enterococcus Faecalis (cultured most frequently in failed RCTs)
Candida albicans
188
Q

What are some advantages of odontopaste over ledermix?

A

Substitution of Tetracycline for Clindamycin (antibiotic) will not result in discolourisation of the tooth

189
Q

What is the mode of action of CaOH2 in the canal?

A
  1. High pH (OH-) release buffers acidic inflammation
  2. Localised cell necrosis
  3. Activates alkaline phosphatase (favours dentine mineralisation)
  4. Inactivates Endotoxins
190
Q

What is the ideal time to leave Ca(OH)2 medicament in necrotic infected cases?

A

2 weeks

191
Q

What are the ideal properties of a medicament?

A
  1. Anti-bacterial
  2. Anti-inflammatory
  3. Ability to stimulate hard tissue growth
  4. Pain reduction
  5. Non-irritant to periapical tissues
  6. Diffuse through dentine
  7. Quick acting
  8. Lost lasting
  9. Effective in the presence of pus and organic debris
  10. Water soluble
  11. Non-staining
  12. Easy to use
  13. Inexpensive
  14. Long shelf life
192
Q

How does enterococcus Faecalis resist alkaline medicaments?

A

Proton Pump to control intracellular pH.

193
Q

Tetracycline Demeclocycline (3.2%) in Ledermix is effective against what and for how long?

A

Bacteriocidal on Day 1 but then becomes Bacteriostatic (66% released in 14 days)

Inactive against yeast

194
Q

Why does Triamcinolone acetonide (Corticosteroid) diffuse faster than Tetracycline (Antibiotic)?

A

Due to it’s lower molecular weight

195
Q

Is Ledermix/Odontopaste largely a corticosteroid or antibiotic paste?

A

Corticosteroid

196
Q

How would you avoid tooth discolourisation if using Ledermix?

A

Limit placement of the paste to below the CEJ.

Or just use Odontopaste

197
Q

What are the active ingredients in Odontopaste?

A

5% Clindamycin Hydrochloride (Antibiotic)

1% Triamcinolone Acetonide (Corticosteroid)

2% CaOH2 (Can contain)

198
Q

What are the issues of mixing CaOH and medicaments?

A

Antibiotics have reduced effectiveness in high pH

Corticosteroids break down at high pH

199
Q

What are limitations to Chlorhexidine in being used as an endodontic medicament?

A
  1. Lack of tissue-dissolving capacity
  2. Not effective against Gram Negative bacteria
  3. Reduced effectiveness in presence of dentine and serum albumin
  4. Not formulated for Endodontic use
200
Q

What issues occur when using Chlorhexidine and Ca(OH)2?

A
  1. Stains by creating a brown precipitate

2. Reduced active CHx in solution

201
Q

What are 3 delivery systems for medicaments?

A
  1. Spiral fillers in a slow speed (Rubber Point placed 4mm short of WL)
  2. Hand files (useful in unprepared canals or canals with sharp curves, can be safer than spiral fillers in terms of fractures)
  3. Injection systems
202
Q

When is the right time to obturate?

A
  1. Tooth is asymptomatic
  2. Draining sinus has healed
  3. No procedural shortcomings
  4. Canal is dry
  5. Radiographic evidence of healing (don’t tend to do this in practice)
203
Q

What are the active ingredients in Ledermix?

A

3.2% Tetracycline Demeclocycline (Antibiotic)

1% Triamcinolone acetonide (Corticosteroid)

204
Q

What is the limit of the extent of obturation?

A

Extent of obturation: to apical constriction only, thereby encouraging apical healing

205
Q

What is objective of obturation?

A

Clean/shape canals and obturate completely with inert, dimensionally stable, biologically compatible material thereby producing an inflammatory free state

206
Q

T/F: Obturation should only take place when the patient is asymptomatic

A

True

207
Q

What are criteria for starting obturation?

A
  • Normal to percussion
  • Normal to palpation
  • No draining sinus
  • Canal can be dried (no bleeding, exudate)
  • Possible resolution of any pre-op periapical radiolucent lesion
  • Negative Culture (Sterile): Success rates are up at 80-95% vs 33-88% if positive culture (more academic)
208
Q

What is the best way to ensure a canal is bacteria free?

A

Instrumentation +
Irrigation +
Medicaments (CaOH for 7-30 days)

209
Q

What are the 13 ideal properties of a root filling?

A
  1. Easily introduced into the canal
  2. Seal the canal apically and laterally
  3. Not shrink after being inserted
  4. Impervious to moisture
  5. Bacteriostatic or at least not encourage bacterial growth
  6. Radiopaque
  7. Not stain the tooth structure
  8. Not irritate the periapical tissues
  9. Sterile, or quickly and easily sterilised before insertion
  10. Easily removed from the root canal if necessary

Extras

  1. Entomb the existing bacteria
  2. Prevent coronal leakage of bacteria
  3. Strengthen the root
210
Q

What is the generate rate of healing if a canal is bacteria free?

A

50% healing within 12 months

211
Q

What are different materials that can be used for obturation

A
  1. Gutta Percha
  2. MTA
  3. Silver Points (no longer used)
  4. Resilon
212
Q

What is a Gutta Percha?

A

A naturally occurring polymer formed by covalent bond long chains and Vanderwaal attractions. It is harvested from a purified coagulated exudate of the Mazer wood tree

213
Q

What tapers are available for GP?

A

0.2, 0.4, 0.6 (very wide taper)

214
Q

What is the composition of GP?

A

20% Gutta-Percha: increases yield strength
60-75% ZnO (filler): increases hardness
1-17% Heavy metal sulphate: radio-opaque
3% Waxes & Resins: increases plasticity/lubricant

215
Q

What is the role of sealant?

A
  1. Fills irregularities and minor discrepancies between G.P. filling and canal wall
  2. Fills accessory canals/multiple foramina
  3. Acts as lubricant and aids seating of G.P. points
216
Q

What are 4 different types of sealants

A
  1. Softened GP (used in Europe)
  2. Zinc oxide eugenol (used in the US)
  3. GIC
  4. Resin based sealers (AH Plus used in clinic)
217
Q

What are ideal properties for sealer?

A
  1. Good adhesion to canal wall
  2. Ample setting time
  3. Hermetic seal
  4. Radio-opaque
  5. Bacteriostatic
  6. Biologically acceptable
  7. Non-staining to tooth structure
  8. Soluble in common solvents (ability to remove for retreatment/posts)
218
Q

T/F: Sealers are fully biocompatible

A

False: they are highly toxic prior to setting, particularly in older formulations containing Paraformaldehyde

219
Q

What happens if sealant is extruded past the apex?

A

1 .Patient might have a bruised feeling, post-operative pain

  1. Small amounts resolve easily over time
220
Q

Which product has a reduced formaldehyde formulation?

A

AH Plus replacing AH/26

221
Q

What are the advantages of AH Plus?

A

Reduced formaldehyde release during setting reaction

Reduced discolouration

222
Q

What are the step in an obturation appointment?

A
  1. Moisture control: Rubber dam + Oraseal
  2. Irrigation -
    Milton’s solution + EDTAC (Removes smear layer from dentine)
  3. Lateral Condensation
223
Q

What tool is used to do lateral condensation?

A

Lateral Spreader

224
Q

What size should the Master GP cone be?

A

The same size as the MAF.

225
Q

What acts as your rubber stopper for length for you GP point?

A

The crimp created by your tweezers after measuring against a ruler

226
Q

What is tug back?

A

A snug fit where there is light resistance when you try to pull the GP out

227
Q

What is used to place sealant in after selecting the master GP point?

A

Sealant filled Lentulo spiral drill at 10000rpm

228
Q

What happens if you can’t get to MAF with 2 sizes of Master GP cones?

A

Cut the longer GP point to create a custom size between the 2.

229
Q

How do you remove excessive sealant in the pulp chamber after searing off the GP?

A

Cotton bud with Methylated Spirits

230
Q

Where should the GP be seared off to?

A

Around the gingival margin / CEJ

231
Q

What are disadvantages of silver points?

A

Prone to Leakage
Poor adaption to the canals
Tend to bind in elliptical canals
Not compressible

232
Q

What do silver points look like?

A

Thin radiopaque line - looks like a broken instrument

233
Q

What 4 conditions aid long term survival of root treated teeth?

A
  1. Tooth restored with a crown after treatment
  2. Tooth with mesial and distal contacts
  3. Teeth not functioning as abutments
  4. Teeth other than molars
234
Q

What criteria of a root filling does Gutta Percha do well in?

A
  1. Easily introduced into the canal
  2. Not shrink after being inserted
  3. Radiopaque
  4. Not stain the tooth structure
  5. Not irritate periapical tissues
  6. Sterile, or quickly and easily sterilised before insertion
  7. Easily removed from the root canal if necessary (before searing)
235
Q

How is AH/26 Sealant formulated and how is it prepared for use?

A

Powder (80% Bismuth trioxide, 20% Methenamine)

Liquid: Bis-phenol – A-D Glycidyl Ether

P + L mixed in 2-3:1 ratio on a sterile glass slab with spatula to a thick creamy consistency when lifted 1.5-2.5mm above glass slab

236
Q

What is the setting time for AH/26 Sealant

A

9-15 hours, so can be prepared early in the appointment

237
Q

What are the properties of AH/26 Sealant?

A
  1. Good working time/flow/setting time
  2. Low toxicity
  3. Well tolerated by periapical tissues
  4. Absorbed by tissues
  5. Toxicity compares favourably with almost all sealers
238
Q

What are potential downsides of Zinc Oxide Eugenol Sealers (Grossman’s Sealer)?

A
  1. Inflammation persists longer than AH/26

2. In high concentration can be reversibly neurotoxic

239
Q

What are issues with using soften GP as a sealant?

A
  1. Very technique sensitive

2. shrinkage of GP which leads to leakage

240
Q

What are issues with Formaldehyde based sealants

(eg N2, endomethasone) ?

A
  1. Irreversibly Neurotoxic with IAN
  2. Low Bio-compatibility
  3. Mutagenic (thus avoid)
241
Q

What are the steps of an obturation appointment?

A
  1. Moisture control: Rubber dam + Oraseal
  2. Irrigation
    Milton’s solution + EDTAC (Removes smear layer from dentine)
  3. Determining Master GP
    Tug Back
    Dry Canal with paper points
    Prepare Sealer on lentulo spiral drill and insert at length at 10000rpm
    Insert Master GP point by hand with sealer
    Radiograph: check the master cone length: ensure its just short of the radiographic apex
  4. Lateral Condensation + Accessory Points
    Master GP is laterally condensed and displaced using a lateral spreader
    Insert lateral spreader 1-2mm below MAF where this is resistance
    Creates room for accessory GP points
    Several accessory points inserted with sealer + laterally condensed
    Radiograph: check for adequate coverage (no voids)
5. Searing GP
Sear off GP to cusp margin
Sear off GP to gingival margin 
Vertically condense with heated amalgam plugger
Final Radiograph
  1. Temporisation of the Canal Prep
242
Q

Can can you determine if a master GP point has reached MAF?

A

1) Crimp should match the stopper point for MAF

2) The master GP should experience tug back

243
Q

What happens if the Master GP Cone is too long?

A

Taper is too thin, try a wider GP point

244
Q

What happens if the Master GP Cone is too short?

A
  1. Try again with another master GP point (points are hand rolled and can vary)
  2. Check if instruments go to length
  3. Recheck working length
  4. Check for presence of debris - instrument and irrigate again
245
Q

Should the master GP point be inserted with sealer in a dry or wet canal?

A

Dry - the canal must be thoroughly dry using paper points prior to placement of master GP

246
Q

How can excess sealant be removed?

A

Wipe with methylated spirits

247
Q

What is the Warm GP technique?

A

The use of a electronic obturation unit where liquid GP is injected to fill the coronal 2/3 after the master GP is inserted an seared at the apical 1/3. The benefits are supposedly coverage in lateral canals

248
Q

What does the left handpiece of an obturation unit do?

A

Sears the master GP at the level of the apical 1/3rd.

249
Q

What does the right handpiece of an obturation unit do?

A

Injects liquid GP into the main and (supposedly) lateral canals

250
Q

What are the advantages of Mineral Trioxide Aggregate (MTA) as a sealant material?

A
  1. Good sealing properties via calcified tissue formation

2. Highly Biocompatible

251
Q

What are the disadvantages of Mineral Trioxide Aggregate (MTA) as a sealant material?

A
  1. Very technique sensitive - difficult to use
252
Q

What is the problem that is trying to be overcome with resilon as a sealer?

A

Resilon claims to provide bonding to tooth structure to form a seal

253
Q

What are limitations of Resilon sealant?

A
  1. Bonding to root dentine is difficult: heterogenous composition and anatomical complexity
  2. Long term mechanical + chemical bonding has limitations
  3. Limited long term studies compared to GP
254
Q

What are limitations of Carrier based system as sealants?

A

Poor length control - likely to push material past apex

255
Q

Is leaking in obturated teeth inevitable?

A

Yes, current methods are not capable in predicting seals that are bacteria tight. Hence the need to ensure coronal seals in the final restoration

256
Q

Why is RCT done on vital pulps?

A

To prevent apical periodontitis from occurring

257
Q

Why is RCT done on non-vital pulps?

A

To treat apical periodontitis

258
Q

Where can bacteria be found in an infected case?

A

Pulp Chamber
Roots
Minor Anatomy: Isthmus, Deltas, Lateral Canals, External Root Surface

259
Q

What is the purpose of isolation in endodontic treatment?

A
  1. Keep pulp out of the pulp system

2. Avoids irritative contact of irrigants with patient’s mouth (Sodium Hypochloride)

260
Q

Which stages of endodontic treatment prevent re-infection?

A

Obturation

Coronal Restoration

261
Q

Which stages of endodontic treatment are concerned with the disinfection of the root canal system?

A

Instrumentation
Irrigation
Medication: left between appointments

262
Q

What are the biological goals of instrumentation?

A

Removal of vital and necrotic tissues from the root canal system

263
Q

What are the mechanical goals of instrumentation?

A

Creation of sufficient space for irrigation and medicaments.

In doing so the following is achieved:

  1. All bacteria removed
  2. Preservation of integrity location of the apical root canal anatomy
  3. Establishment of a convenience form to facilitate root canal filling
264
Q

What is D0?

A

The diameter of the endodontic file at the tip in mm

265
Q

What is D16?

A

The diameter of the endodontic file 16mm from the tip

266
Q

What does 2% taper represent?

A

0.02mm (2%) increase in diameter each mm from the tip

267
Q

In general why would a wider taper be used?

A

Treatment of wider shaped canals

268
Q

What colour is a Size 10 file?

A

Purple

269
Q

What colour is a Size 15 file?

A

White

270
Q

What colour is a Size 20 file?

A

Yellow

271
Q

What colour is a Size 25 file?

A

Red

272
Q

What colour is a Size 35 file?

A

Green

273
Q

What colour is a Size 40 file?

A

Black

274
Q

What colour is a Size 45 file?

A

White

275
Q

What colour is a Size 50 file?

A

Yellow

276
Q

What colour is a Size 55 file?

A

Red

277
Q

What colour is a Size 60 file?

A

Blue

278
Q

What colour is a Size 30 file?

A

Blue

279
Q

What shape are H files handles??

A

Round

280
Q

What shape are K files handles?

A

Square

281
Q

What action should K-files be used?

A

Watch-Winding Technique: ¼ turn and rasping when binding

282
Q

What action should H-files be used?

A

Pull Stroke against the canal walls

283
Q

What is the balance forces technique?

A

Step 1
Pressureless insertion of file
Rotate 90 degrees clockwise with light apical pressure
Advances file into the root

Step 2
Anti-clockwise 180-270 degrees, apical pressure to keep file at same insertion depth

Step 3
As for step 1 but advance instrument more apically

Step 4
After 2-3 cycles, file loaded with dentine shavings and is removed from the canal with a prolonged clockwise rotation

284
Q

What is the use of a barb broach file?

A

Removal of the pulp tissue with the inclusion of barbs on the end to engage the nerve tissue

285
Q

What are the advantages of H (Hedstrom) files?

A

More flexible

Better cutting efficiency

286
Q

What are the disadvantages of H (Hedstrom) files?

A

Increased potential to fracture

287
Q

What are the properties of Stainless Steel files?

A

Rigid - less likely to fracture, but can transport canals

288
Q

What are the properties of Nickel-Titanium files?

A

Flexible and Elastic - can manage curved canls

289
Q

What are the properties of Stainless Steel files?

A

Rigid - less likely to fracture, but can transport canals

290
Q

What are the properties of Nickel-Titanium files?

A

Flexible and Elastic - can manage curved canals. Typically used with rotary endo

291
Q

Where is the anatomical apex vs the radiographic apex?

A

The apical constriction is 0.5mm shallower than the radiographic apex.

292
Q

What is the hybrid approach that we use for instrumentation?

A
  1. Negotiate Canal to Apex
  2. Crown Down: preparation of the coronal 1/3rd using gates-glidden Size 2 and 3 burs to side cut the canals to widen and improve access
  3. Apical Preparation: first file to bind, work to a MAF 2-3 sizes large
  4. Step Back: increase the taper in the canal: 1 file size larger every 1mm from MAF
293
Q

Where is the anatomical apex vs the radiographic apex

A

The apical constriction is 0.5mm shallower than the radiographic apex.

294
Q

What are the properties of Stainless Steel files?

A

Rigid - less likely to fracture, but can transport canals

295
Q

What are the properties of Nickel-Titanium files?

A

Flexible and Elastic - can manage curved canals. Typically used with rotary endo

296
Q

Why is a Size 10-15 file used?

A

It is small enough to negotiate to the apex and is visible on a radiograph

297
Q

What are the 3 instrumentation approaches?

A
  1. Step Back: smallest file to apex, then enlarge coronally
  2. Crown Down - start large coronally and reduce towards apex
  3. Hybrid
298
Q

Where is the anatomical apex vs the radiographic apex

A

The apical constriction is 0.5mm shallower than the radiographic apex.

299
Q

What is the hybrid approach that we use for instrumentation?

A
  1. Negotiate Canal to Apex
  2. Crown Down: preparation of the coronal 1/3rd using gates-glidden Size 2 and 3 burs to side cut the canals to widen and improve access
  3. Apical Preparation: first file to bind, work to a MAF 2-3 sizes large
  4. Step Back: increase the taper in the canal: 1 file size larger every 1mm from MAF
300
Q

What is first file to bind?

A

The file at CWL that snuggly fits and has no lateral wiggling. It should provide resistance when trying to move up or down.

301
Q

What is MAF?

A

File typically 2-3 sizes larger than first file to bind

302
Q

What technique is used to initially negotiate to the apex

A

Passive watch winding technique with a pre-bent file using a Size 10-15 file

303
Q

Why is a Size 10-15 file used?

A

It is small enough to negotiate to the apex and is visible on a radiograph

304
Q

Why is it important to crown down before doing step back?

A

Most bacteria is in the coronal 1/3 so should be removed to prevent “pushing it” towards the apex

305
Q

Why is it important to crown down before doing step back?

A

Reduce infection: Most bacteria is in the coronal 1/3 so should be removed to prevent “pushing it” towards the apex

Prevent blockage: soft tissue risks being clogged towards the apex

306
Q

What defines a red case for difficulty assessment?

A 
Severe Curvature (>30 degrees) 
Unusual anatomy - bifurcation, open apex
307
Q

What is important in angulation of a gates glidden bur?

A

Must be vertical as possible to follow the contour of the coronal 1/3rd of the root.

308
Q

What are reasons for having issues with length?

A

Bend - Insufficient preparation, excessive bends in anatomy
Blockage - inadequate irrigation / recapitulation
Ledge - failure to curve means overworking a canal wall
Transportation - widening of apex laterally.
Calcification - overcome by more crown down

309
Q

Is it possible to recover from transportation?

A

No

310
Q

What is recapitulation?

A

Going back to the canal with a smaller file to dislodge any debris

311
Q

What should be seen with irrigation?

A

Gentle depression that emits a pull of debris filled dentine shavings from the previous files

312
Q

What defines a green case for difficulty assessment?

A

Slight to no curvature (<10 degrees)

313
Q

What defines a yellow case for difficulty assessment?

A

Moderate curvature (10-30 degrees)

314
Q

What defines a red case for difficulty assessment?

A 
Severe Curvature (>30 degrees) 
Unusual anatomy - bifurcation, open apex
315
Q

Is calcification usually an issue with the canal?

A

No - it’s more likely to be an issue coronally

316
Q

Is it possible to recover from ledge?

A

Yes, by pre-bending files

317
Q

Is it possible to recover from Blockage?

A

Yes

  • Copious irrigation and recapitulation
  • Coronal widening
  • Watch winding action to dislodge debris
318
Q

What are the implications of an inaccurate instrumentation to working length?

A

Decrease of 14% success for every 1mm missed

Poor instrumentation diminishes the changes of proper obturation

319
Q

Why would 35% of a canal system still be un-instrumented?

A
  • Presence of lateral canals

- Oval shaped canals: file action not adapted to canal shape adequately

320
Q

What bacterial decrease is possible with instrumentation alone?

A

100-1000x decrease

321
Q

What are the objectives of instrumentation?

A
  1. Creation of sufficient space for irrigation and medication
  2. Establishment of a convenience form to facilitate root canal filling
  3. Preservation of the integrity and location of the apical root canal anatomy
  4. Avoidance of iatrogenic damage to the canal system
  5. Avoidance of further irritation and/or infection of the periradicular tissues
  6. Preservation of sound root dentine to allow long term function of the tooth
322
Q

What is the most important aspect of coronal tooth to maintain during endodontic treatment?

A

A coronal seal to control bacteria. This occurs with:

1) Interim Restoration: replacement of existing restorations that compromise marginal + structural integrity
2) Temporary Restorations: covering endodontic access between appointments

323
Q

How can bacteria enter a tooth between endodontic appointments?

A

Caries
Cracks
Defective restorations
Exposed dentine/pulp

324
Q

How do you gauge bacterial control before commencing endodontic treatment?

A

Assessment of existing restorations, crowns and bridges clinically + radiographs

  • Are margins clinically and radiographically satisfactory?
  • If in doubt, remove restoration
  • Establish long-term prognosis and restorability
325
Q

What is an interim restoration?

A

Placed to replace an existing compromised restoration (poor marginal seal, leaky restoration, cracked restoration) before treatment until the definitive coronal restoration is placed

326
Q

What are the benefits of an interim restoration?

A

1) Ensures good rubber dam isolation - tooth can be isolated
2) Eliminates saliva contamination
3) Eliminates leakage of irrigating solutions
4) Allows use of medicaments

327
Q

What are the properties of an interim restoration?

A

1) Relatively good appearance
2) Easy identification of margins (eg Fuji VII)
3) Good Adhesion
4) Easy to Use
5) Cost Effective
6) Good Mechanical Properties
7) Minimal Tooth Preparation

328
Q

What are materials that can be used for interim materials?

A 
GIC
RMGIC
CR
Amalgam
Reinforced GIC
329
Q

What can be used to improve the structural integrity of an interim restoration?

A

Stainless Steel Orthodontic Band

330
Q

What is a temporary restoration?

A

A restoration place within an endodontic access cavity between endodontic appointments

331
Q

What are properties of a temporary restoration?

A
  • Softer material placed in cavity
  • Strength in minimal bulk
  • Adhere to tooth and/or the interim restoration
  • Easy to handle
  • Quick to place, quick setting and easy to remove
  • Cost effective
  • Not contract
  • Visually apparent - easy to identify as temp
332
Q

What material can be used as a temporary restoration?

A

1) IRM
2) Cavit: good for stopping fluid getting in but mechanical properties poor
3) “Double seal” technique: Cavit (Pulp Chamber) + GIC (Coronal Portion)

333
Q

What is the purpose of an orthodontic stainless steel band for an interim restoration?

A

Reduction of cusp flexure, reducing risk of cusp fracture

334
Q

When should an orthodontic stainless steel band be used for an interim restoration?

A

As general guide use if one or more cusps missing from a tooth (MO / MOD)

335
Q

Which is more important for successful periapical prognosis in endodontically treated teeth: Good Definitive Restoration or Good Endo?

A

Good Definitive Restoration - sound coronal seal prevents further infection

336
Q

T/F: Endodontically treated teeth are more brittle

A

False - issue is quantitative lack of tooth structure rather than qualitative defects with dentine

Analogy: removing pulpal ceiling is like removing the arch of a cathedral - makes it very brittle

337
Q

What endo cases are indicated for immediate permanent restoration?

A

Vital non-infected cases (eg Trauma)

338
Q

What endo cases are contraindicated for immediate permanent restoration?

A

Heavily infected chronic cases with sinus tracts - want to wait 6 months to assess healing

339
Q

Can a tooth still be endodontically treated after being crowned?

A

Yes, access cavity can still be done through the crown.

340
Q

Why might an onlay be a sound choice for a permanent restoration?

A
  • Provides cuspal coverage for high occlusal loads

- More conservative if lots of tooth structure already removed for endo

341
Q

What is the purpose of a post in a permanent restoration after endo?

A

Retain the core in the mouth by providing retention and resistance form (but not physical properties)

342
Q

What is a niacore post?

A

Vertically condensed amalgam in root canal opening as part of an amalgam core

343
Q

Where would you avoid a post?

A

In thin and narrow canals that are hard to reach:

  • B root on Upper Molars
  • M root on Lower Molars
344
Q

What definitive restorations should be done for anterior teeth?

A
  1. Low Tooth Loss: Bonded restoration on access opening

2. Large Tooth Loss: CR or Crown

345
Q

Which teeth are more likely to require a post?

A

Pre-molars: subject to more lateral forces during mastication

346
Q

What are considerations for definitive restorations for molar teeth?

A

Should receive cuspal coverage but in most cases do not require a post

347
Q

What are considerations for removing a post?

A

Ultrasonic usage in canal for long periods can cause necrosis due to heat temperature

348
Q

What forms are needed to completed at SADS as part of endodontic treatment?

A
  1. Titanium Records
  2. Case Difficulty Form
  3. Instrument Plan
  4. Self-Assessment Form
349
Q

What is immunologically similar about apical periodontitis + bisphosphonates usage?

A

Both inhibit osteocytes, making bone healing more difficult

350
Q

Should a dentist start endodontic treatment for a patient with Bisphosphonates, or opt for an extraction?

A

RCT is generally better indicated compared to extraction

351
Q

What are confounding diseases that could mimic dental pain?

A
  1. Recurrent Abscesses (Immunocompromised, Uncontrolled Diabetes)
  2. Bone Pain (Sickle Cell Anaemia)
  3. CNS Issues (Trigeminal Neuralgia / MS)
  4. Referred Pain (Cardiac Angina, Acute Sinusitis)
352
Q

What could be a reason for elective endo?

A

Requiring increased retention/resistance from posts + cores for Fixed Pros

353
Q

What 7 questions could you ask to determine the type of pulpitis?

A
  1. What type of pain: let pt answer but may need to prime – is it sharp or dull, throbbing?
  2. Duration of pain – how long have you experienced the pain? Weeks, months (long time vs short time)
  3. Exacerbating factors – hot/cold, eating, sweet?
  4. How long does pain last? Seconds, minutes, hours “lingers” (30 seconds)?
  5. Does the pain occur spontaneously?
  6. Does it keep you awake at night?
  7. Can you localise the pain? No - Pulpal, Yes - Periapical (PDL can localise)
354
Q

Would you immediately start endodontic treatment for a tooth you suspected reversible pulpitis?

A

No, clinically it’s hard to tell. You would place a dressing, wait a few weeks and assess before deciding to go forward with RCT

355
Q

What are 3 reasons for the high number of medico-legal cases for Endo cases?

A
  1. Failure of RCT: Fracture of files
  2. Failure to communicate: say what can go wrong at the beginning of treatment
  3. Failure to select cases within competency
356
Q

What are the success rates if an obturation is at the wrong length?

A

0-2mm to radiograph apex (94% success)

2mm > to radiographic apex (68%) [Short]

Extruded material (76%) [Long]

357
Q

What are indications for extraction over RCT?

A
  1. Poor Restorability
  2. Poor Periodontal Status
  3. History: Pt doesn’t want more endo done, had
    poor past experience
  4. Time: Inability to attend multiple appointments
358
Q

What are the histological classifications for apical periodontitis and periapical abscesses?

A

Acute

Chronic

359
Q

What are the clinical classifications for apical periodontitis and periapical abscesses?

A

Symptomatic

Asymptomatic

360
Q

Can you identify a Periapical Cyst on a radiograph?

A

No, it only appears radiolucent. Requires excisional biopsy to determine if there is epithelium in the capsule

361
Q

What are 2 types of periapical cysts?

A

True Cyst

Pocket Cyst

362
Q

What are the 9 clinical classifications of periradicular tissues?

A
  1. Normal Periapical Tissue
  2. Apical Periodontitis
  3. Periapical Cyst
  4. Periapical Abscess
  5. Facial Cellulitis
  6. Extra-Radicular Infection
  7. Foreign Body Reaction
  8. Periapical Scar
  9. External Root Resorption
363
Q

What are 2 causes of Acute Apical Periodontitis?

A
  1. Occlusal trauma – tooth may still be vital

2. Bacterial – severely inflamed or necrotic pulp

COPY BDS3 University of Adelaide Dentistry (28 decks)

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