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Advanced Pulpal Disease > Irrigation in endodontics > Flashcards

Irrigation in endodontics Flashcards

1
Q

Endodontic infection

A

Periapical and pulpal infections do not develop without the presence of bacteria
Primary root canal infections are polymicrobial
-dominated by obligate anaerobic bacteria

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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 root canal disinfection

A

Anatomical complexities
Smear layer
Fluid dynamics
Biofilm and resistant microbiota

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4
Q

Anatomical complexities

A

Only 61% of canal walls are instrumented
40% of canal walls remain infected
Irregular and complex systems
Irrigation is the only way of disinfecting majority of root canal system

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5
Q

Irregular and complex systems

A 
Webs
Loops
Cul de sac
Fins
Lateral canals
Apical delta
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6
Q

Smear layer

A

Created during cleaning and shaping

Covers instrumented canal walls

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7
Q

Smear layer consists of

A 
Inorganic substances
Organic substances
Fragments of odontoblastic processes
Microorganisms
Necrotic debris
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8
Q

Problems associated with the smear layer

A

Provides protection for bacteria

Inhibits/ delays penetration of irrigant into dentinal tubules

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9
Q

Fluid dynamics: fluid motion

A

-irrigant only penetrates 1-2mm further than end of needle
-needle tip therefore needs to apical region
Absence of fluid motion
-stagnation plane
-no flushing of debris/ penetration of irrigant into apical region

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10
Q

Fluid dynamics: rules for irrigation

A 
Use side-venting needle
Use Leur-lok syringe
Keep needle tip moving to prevent it wedging and forcing irrigant through apex
Use gentle pressure
If needle binds - stop
Constant agitation to improve fluid flow
Size 27/30 gauge needle
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11
Q

How to improve irrigant exchange in apical region

A

Consider using gutta percha point

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12
Q

Biofilm and resistant microbiota - EPS

A

A biofilm is any group of microorganisms in which cells stick to each other on a surface
These adherent cells are frequently embedded within a selfproduced matrix of extracellular polymeric substance (EPS)
Biofilm EPS (also referred to as slime) is a polymeric conglomeration generally composed of
extracellular DNA, proteins, and polysaccharides.
The microbial cells growing in a biofilm are physiologically distinct from planktonic cells of the same organism, which, by
contrast, are single-cells that may float or swim in a liquid
medium

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13
Q

Steps of biofilm formation

A

Attachment
Colonisation
Growth

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14
Q

Parts of a biofilm

A 
Bulk fluid
Cell cluster
Void
Channel
Streamer
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15
Q

Biofilm is a bacterial layer on internal wall of dentine

A

Irrigants must reach this layer
In biofilm, bacteria are far less susceptible to antimicrobial killing than in planktonic phase
MIC for bacteria in a biofilm are difficult to determine
Biofilm models have demonstrated survival of bacterial biofilms after treatment with antibiotics at concentrations
of 100 to 1000 times the MIC of the same bacteria measured in suspension culture

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16
Q

Resistant microbiota: E. faecalis

A

E.Faecalis exhibits high level of resistance to wide range of antimicrobial agents
Can survive as monoculture in root canals
Cultures of root canals irrigated with NaOCl always yielded +ve cultures with E.Faecalis
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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17
Q

Ideal characteristics of an endodontic irrigant

A
  1. Effective antimicrobial action
  2. Non irritating to the periapical tissue
  3. Stable in solution
  4. Have a prolonged antimicrobial effect
  5. Active in the presence of blood, serum, and protein derivatives of
    tissue
  6. Low surface tension
  7. Not interfere with repair of periapical tissue
  8. Not stain tooth structure
  9. Does not induce cell mediated immune response
  10. Able to completely remove smear layer
  11. Non toxic, non antigenic, non carcinogenic
  12. Has no adverse effects on the physical properties of exposed dentine
  13. Has no adverse effects on the sealing ability of filling materials
  14. Easy to use/apply
  15. Inexpensive
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18
Q

Basic principles of irrigation and mechanical prep

A

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

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19
Q

Rubber dam

A

Mandatory for every endo procedure

20
Q

Current irrigation solutions in endo

A
  1. Sodium hypochlorite (NaOCl)
  2. Ethylinediaminetetraacetic acid (EDTA)
  3. Chlorhexidine (CHX)
  4. Iodine potassium iodide (IPI)
  5. MTAD (Mixture of Tetracycline, acid and
    detergent)
  6. Hydrogen peroxide
  7. Photo-activated disinfection (PAD)
  8. Electronically activated water
21
Q

Advantages of sodium hypochlorite

A
  1. It is the only endodontic irrigant which
    dissolves organic matter – including biofilm
  2. Antimicrobial – effective against all endodontic bacteria
  3. Affordable
22
Q

Sodium hypochlorite - to maintain desired antimicrobial effect when diluted:

A 
Larger volumes of irrigant are required
Increasing time for action required
-0.5% NaOCl: 30min contact time
-2.5% NaOCl: 10min
4% NaOCl: 5 min
5.25% NaOCl: <30sec
23
Q

Increasing the temp - sodium hypochlorite

A

Improve tissue dissolution (0.5% at 45°c equivalence with 5.25%)
60°C completely dissolve tissue but can destroy osteoblast
and cause corrosion of metal instrument.
> antimicrobial effect (double for each 5°c rise)

24
Q

To get optimal effect of NaOCl

A

Continuous replenishment of irrigant
Chlorine ion responsible for tissue dissolving and
antibacterial capacity is rapidly consumed (2 min) especially during the first phase of tissue dissolution

25
Q

Canal wall after prep with rotary nickel-titanium instruments

A

a) using saline as an irrigant
b) using NaOCl for irrigation
Notice that when using NaOCl nearly no remnants of pulpal
tissue or debris were found on the canal wall

26
Q

Disadvantages of sodium hypochlorite

A
  1. Minimally removes dentin debris or smear layers
  2. Affect mechanical dentin properties (reduce flexural strength).
  3. Rare cases of allergic-like reaction causing
    dermatitis
  4. Toxic to vital tissue (hemolysis, epithelial
    ulceration, and necrosis)
  5. Causes corrosion to metal object
27
Q

EDTA

A

Synthetic amino acid
Removes the smear layer as it is a ‘chelating agent’
-a substance with the ability to scavenge up and form
ring-shaped internal complexes with metallic ions,
including calcium
Not bactericidal/static
-but eventually kills bacteria by starvation as metallic
ions needed for growth are chelated
Relatively non-toxic

28
Q

Avoid over-use of EDTA

A

Results in excessive removal of dentine

29
Q

Using EDTA

A 
Available as a solution of 15-
17%
Should be used as a
penultimate rinse for
approx 1-2 mins
Also available as a gel to aid in canal lubrication
30
Q

Citric acid

A

Citric acid is also an effective chelating agent, but less so than EDTA

31
Q

Chlorhexidine

A

Cationic bibiguanide antiseptic
Broad spectrum, attacking multiple sites at a cellular
level making resistance less likely
Bactericidal at high concentrations and static at low concs
Demonstrates substantivity – has a persistant activity
following removal
Used in concentrations of 0.2-2%
Less toxic than NaOCl
No harmful effects to dentine or corrosion of
instruments

32
Q

Chlorhexidine with NaOCl

A

Forms a precipitate when used with NaOCl – para
chloroanaline
-brown precipitate
-potentially carcinogenic
-if used with NaOCl use a intermediate such as saline
No tissue dissolving effects
Cannot remove the smear layer
Potential for severe allergic reaction (very rare)

33
Q

Iodine potassium iodide

A

2% iodine in 4% potassium iodide
Act as an oxidizing agent that attacks key group proteins, nucleotides and fatty acids, leading to cell death
Increasingly favoured in re-treatment and heavily
infected cases – but not used in isolation

34
Q

Advantages of iodine potassium iodide

A

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

35
Q

Disadvantages of iodine potassium iodide

A 
Allergic reaction to iodine
Can stain dentine
Not stable in presence of organic material
No tissue dissolving property
Unable to remove smear layer
36
Q

Hydrogen peroxide

A

Hydroxy-free radicals (•OH) destroy proteins and DNA
Concentrations varying from 3% and 5%
No longer used as routine irrigant

37
Q

Advantages of hydrogen peroxide

A

Active against bacteria, viruses and yeasts

38
Q

Disadvantages of hydrogen peroxide

A

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

39
Q

Mixture of tetracycline, acid, detergent (MTAD) constituents

A

3% doxycycline
4.25% citric acid
A surface active detergent

40
Q

Advantages of MTAD

A

Doxycycline provides broad-spectrum antibacterial effect
Citric acid removes the smear layer
No adverse effect on physical property of tooth

41
Q

Disadvantages of MTAD

A 
Less efficient on biofilm
More toxic than NaOCl
Expensive
Risk of bacterial resistance (Tetracycline)
Risk for tetracycline staining
42
Q

Photo-activated disinfection (PAD)

A

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

43
Q

Advantages of Photo-activated disinfection (PAD)

A

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

44
Q

Disadvantages of Photo-activated disinfection (PAD)

A

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

45
Q

Electronically activated water

A

Electronically Activated Water is also known as
Oxidative Potential Water
Essentially involves electrolysing saline solution
Used commonly to disinfect dental piping and tubing
Creates hypochlorous acid and free radicals which can remove biofilm and destroy bacteria
Lack studies showing the efficacy and safety
Not as effective as 3% NaOCl

46
Q

Which irrigants should we use

A

NaOCI alone produces a superficially clean canal but fails to remove the smear layer
The chelating solutions (eg EDTA) alone effectively
removed the smear layer but left varying amounts of
superficial debris
The current protocol in the hospital is to use NaOCl
throughout the endodontic procedure followed by a
penultimate flush of EDTA
There is no universally accepted protocol for endodontic
irrigation, largely due to the large number of often
conflicting research studies
Iodine may be useful to use as an additional irrigant in
retreatment cases where bacteria may be more resistant
There is increasing support for some of the newer irrigants, however, in addition to effectiveness other factors such as
cost:benefit ratio also need to be considered

47
Q

Ultrasonic agitation of irrigants

A

Irrigant can be activated ultrasonically to
improve the efficacy
Causes ‘acoustic micro-streaming’
Enhances the antibacterial efficiency of the irrigants
Disrupts the biofilm
Can eliminate more bacteria from the root canal than hand instrumentation alone
Can be performed with a standard file connected to an ultrasonic device or with
specific endodontic tips

Advanced Pulpal Disease (7 decks)

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