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Pre-BDS3 Endodontics > Obturation > Flashcards

Obturation Flashcards

1
Q

What is the importance of obturation

A

• Obturation is important to prevent the entry of microorganisms to the root canal system from either the oral cavity, should the coronal restoration leak or fail or via the bloodstream
It is also important to prevent the ingress of tissue fluid which would provide a culture medium for any bacteria remaining within the tooth following treatment

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2
Q

What does the ESE say is important for obturation

A 
• Apical/lateral seal
	• Sealer/core materials 
	• Timing of obturation
	• Length
	• Assessment
Coronal seal
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3
Q

What are the goals of obturation

A
  • Prevent the passage of microorganisms and fluid along the root canal and to fill the whole canal system
  • Not only block the apical foramina but the dentinal tubules and accessory canals
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4
Q

What is a good thing to do prior to filling after root canal prep

A

root canal preparation is verified by taking a radiograph with the instrument or cone inserted to the full working length
• The end point of the inserted instrument or cone and the apex should be visible on this verification radiograph

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5
Q

Where should the prep end

A

at the junction of pulpal and periapical tissue

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6
Q

What should the working length be close to

A

as close as possible to the cemento-dentinal junction

• This is usually the narrowest part of the canal - the apical constriction

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7
Q

How is the working length determined

A

apex locator

radiograph

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8
Q

Describe using a radiograph for working length

A

○ Now as accurate as apex locator
○ The distance of the apical constriction from the apex is 0-3mm
○ Varying constriction anatomy - it may be that the radiographical or anatomical apex could be distant from the terminus of the root canal
○ Increasing with age
○ Root resorption is a complicating factor
If filled to apex then it may be overfilled

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9
Q

What do we want to do with dentinal tubules and lateral canals

A

• We want to seal the dentinal tubules not just the foramina
• The biofilm can often be seen in lateral canals with many inflammatory cells residing in that space and even on obturating there are remnants of bacteria here
Loads of bacteria inside the dentinal tubules

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10
Q

Does bacterial load effect outcome

A

the presence of a positive bacteria culture at time of filling does not influence the outcome

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11
Q

What effect timing of obturation

A 
signs 
symptoms
pulp status
periapical status
difficulty 
px management
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12
Q

How do signs effect timing of obturation

A

Do not want to obturate when px is still in pain or when draining sinus tract hasn’t resolved yet or if there is swelling

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13
Q

How do symptoms effect timing of obturation

A

Do not want to obturate when px is still in pain or when draining sinus tract hasn’t resolved yet or if there is swelling

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14
Q

How does pulp status effect timing of obturation

A

If vital then you may try to obturate in a single visit as at this stage the pulp isn’t infected so delaying can result in colonisation of the space

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15
Q

How does periapical status effect timing of obturation

A

§ If large radiolucency then may be appropriate that you dress it

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16
Q

How does difficulty effect timing of obturation

A

§ Can influence obturation

§ May not be possible to obturate in a single visit

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17
Q

How does difficulty effect timing of obturation

A

Px may be sedated so many impact whether you do single or double visit, long/short visits

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18
Q

What are the ideal properties of materials used to fill the root canal system

A 
○ Biocompatible
○ Dimensionally stable
○ Able to seal
○ Unaffected by tissue fluids
○ Insoluble 
○ Non supportive of bacterial growth 
○ Radiopaque
○ Removable from the canal if retreatment is needed
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19
Q

What should the filling material consist of

A

semi-solid material in combination with a root canal sealer to fill the voids between the material and root canal wall

20
Q

What is the most common core material

A

GP

21
Q

What is GP produced from

A
  • Produced from juice of trees of the sapodilla family
    • Natural rubber and gutta percha are polymers of the same monomer (isoprene)
      It is a trans isomer of polyisoprene
22
Q

What do GP cones consist of

A

○ 20% GP
○ 65% zinc oxide
○ 10% radiopacifiers
○ 5% plasticizers

23
Q

What are the different GP obturation techniques

A

○ Sealer based obturation
○ Sealer with GP
○ Bits of GP and sealer
○ Lots of GP and minimal sealer

24
Q

What are the diff obturation techniques

A

cold lateral compaction
warm vertical compaction
continuous wave obturation

25
Q

What is cold lateral compaction

A
  • Most commonly taught and practiced filling technique
    • Regarded as the benchmark against which other obturation techniques are evaluated
    • Can be done without complex equipment
      Low cost and ability to control the length of the fill are ideal
26
Q

What are problems with cold lateral compaction

A

○ Voids (can be overcome with thermal techniques)
○ Spreader tracts
○ Incomplete fusion of GP cones
Lack of surface adaption (if we provide sufficient lateral compaction then should have good surface adaption)

27
Q

What are sized matched cones

A
  • They complement file size and shape
    • Leave very little space for accessory cones
    • They have a tight apical fit
    • Often it results in a single point obturation which if there is good length control and the sealer is reliable can have very similar outcomes to other techniques
28
Q

What is warm vertical compaction

A
  • Schilder introduced this is a method to achieve 3D obturation
    • It requires a continuously tapering funnel and minimal apical diameter
29
Q

What is the procedure for warm vertical compaction

A
  1. Place cone within RCT space and sever off using heated plugger and plug apically
    2. Sequentially remove more and more GP putting apical pressure sequentially and this results in an apical plug of GP which is a few mm in length and the GP and sealer flow well into lateral anatomy
    Its of warm GP go on top of the apical plug and then fill the space resulting in a complete 3D obturation of the root canal system
30
Q

What is continuous wave obturation

A
  • Uses electrically heated pluggers and electrically heated GP in guns to deliver and remove GP in a continuous wave
    allows good obturation of 3d space
31
Q

What is the procedure for continuous wave obturation

A
  1. Gp cone is fitted and the plugger is fitted
    1) Should go 4-6mm from the terminus of the prep
    2. Place cone with sealer
    3. Sever coronal portion with plugger
    4. Pack apically
    5. Plunge heated plugger into mass of GP in one continuous motion unlike the warm vertical compaction and the heated tip should be placed within the GP point where it binds apically
    6. Apical pressure is maintained while heat is removed
    7. Tip and GP cool while putting apical pressure and add a quick burst of heat and remove the plugger and with it should come the coronal GP mass leaving only an apical plug
    Then do a back fill using warmed GP and one of the guns delivering flowable warm GP and then add apical pressure
32
Q

What is carrier based obturation

A
  • Uses heat and GP
    • Oven is used to warm GP and place into root canal space
    • You get effective flow of GP and the core of the GP carrier stays within the root canal
    • Get a very good fill and not many voids
      Good for curved canals but not good for wide straight canals because we lack apical control and the GP may go into the surrounding space
33
Q

What are bioceramic cements

A
  • It is not always suitable to use GP
    • If there is not a nice tapered funnel shape with a good apical diameter then can’t use GP
    • Can use bioceramic cements such as biodentine, MTA ect and these are materials we use to fill the more complex spaces
    • MTA when placed stimulates a tissue response which is helpful and it good for larger apices
      MTA obturation showed comparable filling quality to GP with sealer
34
Q

What is the function of the sealer

A
  • Seals space between dentinal wall and core material
    • Fills voids and irregularities in canal, lateral canals and between GP points used in lateral condensation
    • Lubricates the GP during obturation so it is placed readily without interference
35
Q

What are properties of an ideal sealer

A
  • Exhibits tackiness to provide good adhesion
  • Establishes a hermetic seal
  • Radiopacity
  • Easily mixed
  • No shrinkage on setting
  • Non-staining
  • Bacteriostatic or does not encourage growth
  • Slow set
  • Insoluble in tissue fluids
  • Tissue tolerant
    Soluble on retreatment
36
Q

What is zinc oxide eugenol based sealer

A
  • Zinc oxide is an effective antimicrobial and may afford cytoprotecting
    • Resin acids affect lipids in cell membrane thus strong antimicrobial/cytotoxic
    • Although toxic, may overall be beneficial with long lasting AM effect combined with cytoprotective effects
    • Free eugenol which remains can act as an irritant
    • Lose volume with time due to dissolution, resins can modify this
      The ZOE is slightly unstable, over time the sealer with dissolve and may break down the apical seal
37
Q

What are some GI sealer features

A
  • Advocated due to dentine bonding properties
  • Minimal antimicrobial activity
  • Greater solubility
  • Removal upon retreatment is difficult
  • Little clinical data to support use
38
Q

What are the factors of resin sealers

A
  • Long history of use
    • Epoxy resin
    • Paste-paste mixing
    • Slow setting - 8 hours
    • Good sealing ability and the seal is stable with time
    • Good flow
    • Initial toxicity declining after 24 hours
    • endoRez is a UDMA resin-based sealer
    • Hydrophilic
    • Good penetration into tubules
    • Biocompatible
      Good radio-opacity
39
Q

What are the calcium silicate sealers

A
  • High pH (12.8) during the initial 24 hours of the setting
    • Hydrophilic
    • Enhanced biocompatibility
    • Does not shrink on setting
    • Non restorable
    • Excellent sealing ability
    • Quick set - 3 to 4 hours and requires moisture
    • Easy to use
      Expensive however
40
Q

How do you decide which sealer

A
  • Depends on obturation technique
  • Some sealers are not compatible with heating
  • For bioceramic sealers there is more potential to use a greater bulk of sealer
    Sealers containing organic materials such as aldehydes are not recommended as they are cytotoxic and potentially carcinogenic
41
Q

What do we do after filling of root canal

A
  • Quality of filling should be checked with a radiograph
  • Radiograph should show root apex with preferably at least 2-3mm of the periapical region clearly identifiable
  • The prepared root canal should be completely filled unless space is needed for a post
  • The prepared and filled canal should contain the original canal
  • No space between canal filling and canal wall should be seen
  • There should be no canal space visible beyond the end-point of the RC filling
    The tooth should be adequately restored after root canal filling to prevent bacterial recontamination or fracture of the tooth
42
Q

How do we assess obturation

A
  • Primary based on post op radiograph
    ○ Length - 2mm within apex?
    ○ Taper
    ○ Density - well condensed?
    ○ GP and sealer removed to facial CEJ in anteriors and canal orifice in posteriors
    § Important as there is risk of leakage from exposed cementum
    § Also GP is not good base for restorative material
    ○ Somewhat subjective
    ○ Errors of obturation may be corrected
43
Q

What is more important, coronal or apical seal

A
  • Need equally good seals to ensure best outcome

The quality of restoration is important too

44
Q

How do we close the orifice

A
  • Finish obturation at orifice level or just below orifice level
    • GP rapidly becomes infected if exposed directly to oral bacteria
    • ZnO/eugenol materials are cytotoxic and form effective antibacterial barrier
      RMGI or flowable composite to create a primary seal so if the provisional resotration fails we can maintain an adequate seal
45
Q

What is the verdict on obturation

A
  • Complete obturation contributes to success
    • Assays not always reliable or relevant
      ○ Amount of disinfection not that relevant
    • Outcome studies are important but not uncomplicated
    • Anecdotal evidence often has been adopted
      Classic materials have stood the test of time

Pre-BDS3 Endodontics (13 decks)

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