Smear Layer Removal/intracanal Medicaments/temporary Restorations Flashcards
What creates the smear layer? How thick is it?
Cleaning and shaping. 1-5 micrometers
Organic components of smear layer?
Pupal remnants, odontoblasts, microorganisms
Inorganic components of smear layer?
Dentin, irrigant remnants, hydroxyapatite
3 reasons why a smear layer may affect the prognosis of RCT?
- Sealed dentin tubules prevents adequate penetration of the irrigant into the tubules
- Results in poor adaptation of the sealer and obturation material to the canal walls
- May allow bacterial growth within
What type of solution do we use to remove the inorganic components of the smear layer?
Chelator solutions
What do we use to remove the organic component of smear layer?
Sodium hypochlorite for no more than 1 minute
How does the use of chelator solutions improve the use of sodium hypochlorite use?
Allows deeper penetration of sodium hypochlorite into dentin tubules
What is the problem with excessive sodium hypochlorite rinsing after use of a chelator solution?
Could result in corrosion of the dentin
What chelator solution do we use in clinic? How long do we rinse canals with this?
17% EDTA - ethyldiaminetetracetic acid
1 minute
3 properties of EDTA (chelating solution)?
- Minimal-no antimicrobial activity
- Non-lubricating
- Allows deeper penetration of irrigant and sealer
3 other smear layer removal products other than EDTA?
- MTAD
- Citric acid
- Smear clear
After we used chelator (17% EDTA) for 1 min and then sodium hypochlorite for minute. How do we dry the canals for placement of sealer and obturation material?
Dry canals with paper points
What is the purpose of using intracanal medicaments? (3 points)
- Persistent anti-microbial effect
- Improves prognosis of long term microbial colonized canals that have resistant microbiota
- Acts as a physical-chemical barrier to reinfection between final obturation and restoration
What is the most common intracanal medicament?
CaOH
Why is CaOH an effective intracanal medicament? How long does it take to have an effect?
Because it has a high pH of 12.5.
Takes 1-2 weeks to take effect (sufficiently change the pH of the canals.
What are 4 specific actions of intracanal medicament (CaOH)?
- Denature proteins
- Inactivate DNA
- Inactivate LPS
- Stops/decreases resorption
Is the use of intracanal medicaments scientifically proven?
When do they not provide amazing results?
Not really. Questionable effectiveness
Not amazing with persistent or secondary infections because the bacteria involved in these are resistant to long term pH changes.
What are 5 indications for the use of intracanal medicaments?
- Treatment of vital or necrotic canals
- Used to dry weeping or wet canals
- Used in between visits when resorption is suspected
- Used in between visits as a chemical-physical barrier to saliva contamination of there is a faulty temporary restoration
- Large periapical infections that indicate a long term infection.
What is the purpose of a temporary restoration during RCT?
Why?
Purpose is to prevent bacterial contamination before Permenant restoration is done.
Why?
- ease of placement
- allows easy removal (easy identification/minimal bonding)
- cheap
What are 3 common problems when placing a temporary restoration?
- inadequate thickness of temp resto
- Poor placement
- Failure to evaluate occlusion
What are the 4 common materials to use in temporary restorations?
- Cavit
- IRM - intermediate restorative material
- Restorative glass ionomer
- Click/TERM (temporary endodontic restorative material)
What are the indications for IRM temp resto? What is minimum depth?
Posterior teeth
Minimum 4 mm in depth
What are 4 properties of IRM?
- Resistant to occlusal load
- Resistant to wear
- Less soluble than others
- Doesn’t prevent fluid leakage that well
When is Cavit temp resto material indicated?
Best indicated for anterior teeth
4 properties of Cavit?
- Good seal (expansion of material when contacting fluid)
- premixed
- Poor compressive strength
- Poor wear resistance
What are the properties of RGI?
If it’s so damn good why isn’t it used all the time?
- Adhesive
- Great seal
- Good wear resistance
- Good function under occlusal load
Because it is difficult to remove and may cause excessive tooth structure removal
What are some properties of TERM?
Convenient for use
Dispensed in compiles like composite is
Light cured
Seal equivalent to IRM
What is the maximum amount of time a temp resto of IRM or Cavit should be used for?
3 months, after wards its integrity is compromised (leakage)
When is the best time to place a Permenant restoration?
Right after endodontic treatment
What type of temp resto material should you use if it’s gonna be long term?
RGI - restorative glass ionomer
