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DEN304 - IODC > Irrigation in Endodontics > Flashcards

Irrigation in Endodontics Flashcards

Mark Barber

1
Q

Endodontic infection

Primary RCTs are

A

Periapical and pulpal infections do not develop without the presence of bacteria

Polymicrobial

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2
Q

Aims of irrigation

A

Killing and removal of microorganisms
Removal of necrotic/inflamed tissue
Removal of dentine debris and smear layer
Provides lubrication and reduces friction for
instrumentation

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3
Q

Obstacles in RCT disinfection

A

Anatomical complexities
Smear layer
Fluid dynamics
Biofilm and Resistant Microbiota

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4
Q

Anatomical complexities - purpose and examples

A

Only 61% of walls are instrumented
therefore 40% of canals remain infected after instrumentation

 Webs
 Loops
 Cul de sac
 Fins
 Lateral canals
 Apical delta
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5
Q

What does mechanical instrumentation do

Irrigation is..

A

Creates funnel shape as pathway for chemical instrumentation
Only way to disinfect majority of root canal system

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6
Q

Smear layer

Consists of??

A

Created during cleaning and shaping
Covers instrumented canal walls

Inorganic substances
Organic substances
Fragments of
odontoblastic processes
Microorganisms
Necrotic debris
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7
Q

Problems associated with smear layer

A

Protection for bacteria

Inhibits/delays penetration of irrigant into dentinal tubules

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8
Q

Fluid dynamics

Fluid motion

A

As close to apex as possible

  • 1-2mm penetration further than needle end
  • Needle tip needs to be close to apical region

Stagnation plane is created - debris accumulates
No flushing of debris/penetration of irrigant into apical region

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9
Q

Rules for irrigation

A

Side-venting needle
Use a luer-lok syringe
Keep the needle tip moving to prevent it wedging and forcing irrigant through the apex
Use gentle pressure
If the needle bends - stop
Constant agitation to improve fluid flow
Size 27/30 gauge needle

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10
Q

GP role

A

Use GP point to improve irrigant exchange in the apical region

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11
Q

Biofilm

A

Exists within canals
Adhere to dentinal walls
Distinct from planktonic cells and are 100x more resistant than coronal bacteria

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12
Q

Stages of biofilm formation

A

Attachment
Colonisation
Growth

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13
Q

Biofilm stats

What must reach this layer?

Where are bacteria less susceptible to antimicrobial killing?

A

Biofilm is a bacterial layer on internal wall of dentine -

Irrigants must reach this layer In biofilm, bacteria are far less susceptible to antimicrobial killing

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14
Q

Resistant Microbiota

Which bacteria exhibit high level of resistance? - most frequent species in reinfection of RT teeth

Where can they survive?

Why are they responsible?

A

E. faecalis

Can survive as monoculture in root canals
E. faecalis is the most frequent species in root-canal
treated teeth, with prevalence values reaching up to
90% of the cases
E. Faecalis association with failure of endodontic treatment is at least partially, from high resistance of this species to NaOCl’

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15
Q

Ideal characteristics of an endodontic irrigant

A 
Effective action 
Non irritant 
Stable 
Prolonged effect
Active in presence of bodily tissues 
Low surface tension 
Not stain tooth structure 
Does not induce cell mediated response 
Able to remove smear layer 
non-toxic, non antigenic, non carcinogenic 
No adverse effects on physical properties of exposed dentine 
No adverse effect on sealing ability 
Easy 
Expensive
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16
Q

Basic principles of preparation

Mechanical prep must allow?

A

A combination of mechanical preparation
and irrigation with appropriate chemicals
is a fundamental principle of endodontics
– hence the term ‘chemo-mechanical
preparation’
Mechanical preparation must be sufficient
to allow penetration of the irrigant to the
apical region of the canal

17
Q

Current irrigation solutions

A

NaOCl
CHX
H2O2

18
Q

Advantages of NaOCl

A

Dissolves organic matter including BIOFILM and dentine debris
Antimicrobial effect against ALL endodontic bacteria
Affordable

19
Q

To maintain desired effect when diluted - use

A

Larger volumes

Increased time of action

20
Q

How to increase efficiency of NaOCl

Optimal effect?

A

Increase temp = increased tissue dissolution
60 degrees dissolves tissue but can also destory osteoblasts
x2 effect for every 5 degree rise

Continous replenishment of irrigant to get optimal effect of NaOCl

21
Q

Disadvantages of use of NaOCl

A

Minimal smear layer removal Affects mechanical dentine properties
Rare cases of allergic reactions
Toxic to vital tissues
Causes metallic corrosion

22
Q

EDTA - what is it

Avoid overuse because

Use - instructions

A

Synthetic amino acid
Removes smear layer as it is a chelating agent (same as citric acid)
Not bactericidal but eventually kills bacteria
Non toxic

Results in excessive removal of dentine

Penultimate rinse for 1-2 mins

23
Q

Chlorhexidine is

Disadvantages

A 
Broad spectrum 
Bactericidal at low and static at high concs
Persistent activity following removal 
Less toxic 
No harmful effects

Forms brown precipitate
Use intermediate eg saline if using with bleach
Cannot remove smear layer
Potential for allergic reaction

24
Q

Iodine/potassium iodide - what is it

Mechanism

A

2% iodine in 4% potassium iodide

Oxidising agent which attacks key group proteins, nucleotides and fatty acids –> cell death

25
Q

Iodine/potassium iodide -
Works against -
Advantages

Disadvantages

Favoured in?

A

Broad spectrum including against Efaecalis, P. Aeruginosa and yeast species
Substantive effects
Low toxicity relative to NaOCl

Allergic reaction to iodine
• Can stain dentine
• Not stable in presence of organic material
• No tissue dissolving property
• Unable to remove smear layer

Re-treatment

26
Q

H2O2 - what is it - mechanism

Advantages

Disadvantages

Is it used?

A

Hydroxy-free radicals (•OH) destroy proteins and DNA
- Concentrations varying from 3% and 5%

  • Active against bacteria, viruses and yeasts.
  • Antimicrobial efficacy is poorer than NaOCl
  • Less tissue dissolving capacity than NaOCl
  • Can release O2 gas (bubbles)
  • Potential danger: seepage into the tissues may lead to air
    emphysema.
  • No longer used as routine irrigant
27
Q

Mixture of tetracycline, acid and detergent

Roles of each component

Mechanism

Advantages

Disadvantages

A

Doxycycline is antimicrobial
Citric acid takes smear layer away
Detergent disinfects

Doxycycline provides broad-spectrum antibacterial effect
- Citric acid removes the smear layer

No adverse effect on physical property of tooth.

Less efficient on biofilm

  • More toxic than NaOCl
  • Expensive
  • Risk of bacterial resistance (Tetracycline)
  • Risk for tetracycline staining
28
Q

Ideal protocol
NaOCl and EDTA

Current protocol

A

NaOCI alone produces a superficially clean canal but fails
to remove the smear layer.
EDTA left superficial dentine behind

The current protocol in the hospital is to use NaOCl
throughout the endodontic procedure followed by a
penultimate flush of EDTA

29
Q

Ultrasonic agitation - mechanism

A

Activates irrigant ultrasonically to improve efficacy
Causes acoustic micro streaming
Enhances antimicrobial efficiency
Disrupts biofilm
Can eliminate more bacteria from the root canal
Can be performed with a standard file attached to ultrasonic tip

30
Q

PAD

A

Photo-activated disinfection

  • A dye (often toluidine blue) is introduced
    to the root canal
  • A low power laser is then used to activate
    the dye
  • The photosensitiser molecules attach to
    bacteria and following the introduction
    of the laser irradiation, oxygen is
    produced which ruptures the cell wall
31
Q

PAD

advantages

disadvantages

A

Broad-spectrum of activity with little risk of
resistance
May destroy some bacteria left by some other
irrigants
No risk of toxicity

Efficacy depends on power, length of exposure,
absorption of light into tissues and distance from
tip-to-target
No evidence to suggest any benefit over other
irrigants
Expensive

DEN304 - IODC (58 decks)

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