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APD > Irrigation > Flashcards

Irrigation Flashcards

1
Q

Endodontic infection:

A

Periapical and pulpal infections do not develop without the presence of bacteria (kakehasi et al 1965
Primary root canal infections are polymicrobial - dominated by obligate anaerobic bacteria - siqueria 2009

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2
Q

What are the aims of irrigation?

A

Killing and removal of micro-organisms
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

What are the obstacles in the root canal disinfection?

A

Anatomical complexities
Smear layer
Fluid dynamics
Biofilm and resistant microbiota

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4
Q

What are the different anatomical complexities?

A

only 61% of the canal walls is instrumented (Mannan et al 2001)
40% of walls remaing infected after instumentation

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5
Q

What are the irregular and complex systems?

A 
apical 2-3mm lots of exits of the canal
Webs 
Loops 
Cul de sac
Fins 
Lateral canals
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6
Q

When is the smear layer created? What area does it cover?

A

Created during the cleaning and shaping process

Covers the instrumented canal walls

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7
Q

What does the smear layer consist of?

A 
Inorganic substances
Organic substances
Fragments of odontoblastic processes
Micro-organisms 
Necrotic debris
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8
Q

What are the problems associated with the smear layer?

A

Provides protection for the bacteria

Inhibits/delays penetration of irrigant into dentinal tubules

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9
Q

What is fluid dynamics?

What is the problem with fluid dynamics?

A

The way fluid penetrates and flows into the RC
Irrigant
Irrigant only penetrates 1-2mm further than the end of the needle
Needle tip needs to be as close to the apex as possible - need to shape the canal to allow this

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10
Q

What happens in the absence of fluid motion?

A

Get stagnation phase, get dentine debris full of bacteria, accumulates bacteria - wont get cleaning of the area
No flushing of debris/penetration of irrigant into the apical region

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11
Q

What are the rules for irrigation?

A

Use a side-venting needle - creates a swirl of irrigant so not a fast and hard jet of fluid
Use a Luer-lok syringe
Keep the needle tip moving to prevent wedging and forcing the irrigant through the apex
Use gentle pressure
If the needle binds, stop
Constant agitation to improve fluid flow
size 27/30 gauge needle

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12
Q

How can the GP point be used during irrigation

A

Consider using a GP point to improve irrigant exchange in the apical region
Take the master GP point, flood canal with irrigant, put the GP point in to disturb the stagnation area

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13
Q

What is a biofilm?

A

Any group of micro-organisms in which cells stick to each other on a surface
These cells are frequently embedded within self-produced matrix of extracellular polymeric substance (EPS)

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14
Q

What is biofilm extracellular polymeric substance?

A

a polymeric conglomeration generally composed of extracellular DNA, proteins, and polysaccharides

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15
Q

How are the microbial cells different when growing in a biofilm?

A

Physiologically distinct from planktonic cells of the same organism which are single cells that may float or swim in a liquid medium

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16
Q

Which are more difficult to remove?

A

Biofilm - plaques adhere to the dentinal walls

Fluid phase planktonic organisms - get flushed out with needle tip

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17
Q

What is the problem if have multiple species in the canal?

A

Protection from other species and get channels forming more difficult for irrigant to remove and penetrate into

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18
Q

How does a biofilm form on the surface?

A

Attachment -> colonisation -> growth

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19
Q

Bioflim…

A

Bacterial layer on internal wall of dentine - irrigants must reach this layer

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20
Q

what do you need to do first if trying to kill bacteria in a biofilm?

A

dissolve and remove the organic matter

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21
Q

What it the most resistant microbiota?

A

E.faecalis - high level of resitance to wide range of antimicrobial agents
Can survive as monoculture in root canals

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22
Q

What is the most frequent species in RC treated teeth?

A

E.faecalis - prevalence 90% cases

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23
Q

Why is E.faecalis most commonly associated with failure of endo treatment?

A

High resistance to NaOcl

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24
Q

What are the ideal characteristics of an endodontic irrigant?

A

Effective antimicrobial action
Non-irritating to periapical tissue
Stable in solution
Have prolonged antimicronial effect
Active in the presence of blood, serum and protein derivatives of tissue
Low surface tension
Not interfere with repair of periapical tissue
Not stain tooth structure
Does not induce cell mediated immune response
Able to completely remove smear layer
Non-toxic, non-antigenic, non-carcinogenic
Has no adverse effects on the physical properties of exposed dentine
No adverse effects on the sealing ability of filling materials
Easy to use/apply
Inexpensive

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25
Q

What is chemo-mechanical preparation?

A

A combination of mechanical preparation and irrigation with appropriate chemicals - fundamental principle of endodontics

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26
Q

Why must mechanical prep be sufficient?

A

to allow penetration of the irrigant to the apical region of the canal

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27
Q

What are the basic principles?

A

Rubber dam
Canal prep with lots of irrigation
Mechanical prep - sufficient to allow penetration of the irrigant to the apical region of the canal
Chemo-mechanical prep

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28
Q

What are the current irrigation solutions in endodontics?

A
  1. Sodium hypochlorite (NaOCl)
  2. Ethylinediameteraacetic acid (EDTA)
  3. Chlorhexidine (CHX)
  4. Iodine potassium iondide (IPI)
  5. MTAD (mix of tetracycline, acid and detergent)
  6. Hydrogen peroxide
  7. Photo-activated disinfection (PAD)
  8. Electronically activated water
29
Q

What are the advantages of sodium hypochlorite

A
  1. It is the only endodontic irrigant which dissolves organic matter - we use 1.5%, biofilm, necrotic pulp in bleach will dissolve it
  2. Antimicrobial - effective against all endodontic bacteria
  3. Affordable
30
Q

If the NaOCl is diluted, what do you need to maintain desired effect?

A

Larger volumes of irrigant required

Increasing time for action required

31
Q

For these different concs of NaOCl what is the contact time?

  1. 5%
  2. 5%
  3. 0%
  4. 25%
A
  1. 5% 30mins
  2. 5% 10mins
  3. 0% 5 mins
  4. 25% <30secs
32
Q

What happens when increase the temp of NaOCl?

A

Improve tissue dissolution (0.5% at 45 degrees = 5.25%)

Increases the antimicrobial effect - doubles for each 5 degree rise

33
Q

What happens if increase to 60 degrees C

A

Completely dissolves tissue but can destroy odontoblasts and cause corrosion of metal instrument

34
Q

Why do you need to continuously replenish the irriganr?

A

to get optimal effect of NaOCl
Chloride ion that is responsible for tissue dissolveing and antibacterial capacity is rapidly consumed especially during first phase of tissue dissolution

35
Q

What are the disadvantages of sodium hypochlorite?

A

Minimally removes dentine debris or smear layer
Affects mechanical dentin properties (reduces flexural strength)
Rare cases of allergic-like reaction causing dermatitis
Toxic to vital tissues - haemolysis, epithelial ulceration and necrosis
Causes corrosion to metal object

36
Q

When do you get corrosion to metal object when using NaOCl?

A

Corrosion of NiTi 2 hours at 60 degreesC - we use single use files, so wont be in contact for long time. Otherwise increase risk of fracture

37
Q

What is EDTA?

A

Synthetic amino acid

Removes the smear layer and is a chelating agent - good for inorganic components but not bacteriacidal

38
Q

What does EDTA do?

A

Substance with the ability to scavenge up and form ring-shaped internal complexes with metallic ions, including calcium

39
Q

EDTA isn’t bactericidal, but what does it have the ability to do?

A

Eventually kills bacteria by starvation of metallic ions needed for growth

40
Q

What does the EDTA allow to also be used?

A

Removes smear layer and opens tubules, means the hypochloride can still kill the bacteria in tubules

41
Q

What does over-use result in?

A

Excessive removal of dentine

42
Q

What solutions are available?

How should it be used?

A

15-17%

Should be used as a penultimate rinse for approx 1-2mins, available as a gel to aid canal lubrication `

43
Q

What is chlorhexidine?

A

Cationic bibiguanide antiseptic

Broad spec, attacking multiple sites at a cellular level making resistance less likely

44
Q

What are the properties of chlorhexidine?

A

bactericidal at high concs and static at low concs
Demonstates substantivity - persistency activity after removed
Used in concs 0.2-2%
Less toxic than NaOCl
No harmful effects or corrosion to intruments

45
Q

What are the disadvantages of chlorhexidine?

A

Forms a precipitate when used with NaOCl - parachloroanaline
No tissue dissolving effects
Cannot remove the smear layer
Potential for severe allergic reaction

46
Q

What is the percipitate that is formed when use chlorhexidine and NaOCl

A

Brown percipitate
Potentiall cacinogenic
Need to use an intermediate such as saline

47
Q

What is iondine potassium iodide made up of?

A

2% iodine in 4% potassium iodide

48
Q

What is iodine potassium iodide?

A

Acts as an oxidising agent that attacks key groups of proteins, nucleotides and fatty acids, leading to cell death

49
Q

What are the advantages of using iodine potassium iodide?

A

Broad spec, including E. faecalis, P.Aeruginosa and yeast species
Substantive effects
Low toxicity relative to NaOCl

50
Q

What are the disadvantges of using 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
51
Q

When is iodine potassium iodide heavily favoured?

A

in re-treatment and heavily infected cases

52
Q

How does hydrogen peroxide work?

A

if gets into tissue, get emphysema

Hydoxy-free radicals destroy proteins and DNA

53
Q

What are the different concs of hydrogen peroxide?

A

Concentrations varying from 3% to 5%

54
Q

What are the advantages of hydrogen peroxide?

A

Active against bacteria, viruses and yeasts

55
Q

What are the 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 tissues may lead to air emphysema

56
Q

What is MTAD?

A

A mix of tetracycline, acid and detergent
3% doxycycine
4.25% citric acid
A surface active detergent

57
Q

What are the advantages of MATD?

A

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

58
Q

What are the disadvantages od MATD?

A 
Less efficient on biofilm
More toxic than NaOCl 
Expensive 
Risk of bacterial resistance (tetracycline)
risk of tetracycline staining
59
Q

What is PAD?

How does it work?

A

Photoactivated disinfection
A dye is introduced to the RC - often toludine blue is used
A low power laser is then used to activat the dye
The photosensitiser molecules attach to bacteria and following the introduction of the laser irradiation, singlet oxygen is produced which ruptures the cell wall

60
Q

What are the advantages of PAD?

A

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

61
Q

What are the disadvantages of 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

62
Q

What is electronically activated water?

A

Oxidative potential water
Essentially involves electrolysing saline solution
Used commonly to disinfect dental tubing and piping

63
Q

How does electronically activated water work?

A

Creates hypochlorous acid and free radicals which can remove the biofilm and destroy bacteria

64
Q

What are the disadvantages of electronically activated water?

A

Lack of studies showing efficacy and safety

Not as effective as 3% NaOCl

65
Q

Which irrigant should we use?

A

NaOCl produces a superficially clean canal but fails to remove the smear layer
The chelating agents - EDTA effectively remove the smear layer but leave superficial debris

66
Q

What is the protocol for the hospital?

A

use NaOCl throughout the endodontic procedure followed by penultimate flush of EDTA - when ready to obturate use EDTA 1 syringe and then go back to hypochlorite for final rinse

67
Q

What is the ultrasonic agitation

A

Irrigant can be actively unltrasonically to improve the efficacy

68
Q

How does ultrasonic agitation work?

A

Creates acoustick micro-steaming - allows penetration where cant get in with file, spreads irrigant around
Enhances the antibacterial efficiency of the irrigants
Distrupts the biofilm
Can eliminate more bacteria from the root canal than hand instumentation alone
Can be preformed with standard file connected to an ultrasonic device or with specific endodontic tips
More irrigant that can get down -> more bacteria will be removed -> and more successful it will be

69
Q

Why is NaOCl considered gold standard?

A

excellent antimicrobial activity and ability to dissolve organic tissue

APD (9 decks)

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