Endo Flashcards
What is the pathway of development for enamel?
Ectoderm to enamel organ, to ameloblasts to enamel
What is the pathway of development for the root?
Enamel organ to HERS to root formation
What is the pathway of development for the pulp cells?
Ectomesenchyme to dental papilla to pulp cells
Pulp cells are mostly:
Fibroblasts, but also odontoblasts
Why not just proceed immediately with root canal?
We want to maintain vitality, delay the restorative cycle, and not significantly weaken the tooth
Why is an irreversible pulpitis tooth potentially able to heal, but not a necrotic pulp?
Necrotic pulps have no capacity to heal as they have no viable cells to create a dentine seal
Describe pulp testing response of asymptomatic irreversible pulpitis
Usually respond normally to thermal testing, but may have had trauma or deep caries that would likely result in a pulp exposure
Pulp Necrosis alone does not cause apical periodontitis, unless the canal is infected with microbes. True or false
True
Why might a pulp not respond to pulp testing, aside from necrosis
Calcification, large restorations, recent history of trauma
What are the advantages of selective etch?
Preserve dentine spear plugs so less irritation and post op sens compared to total etch.
What is the key advantage of composite resin over amalgam
Micromechanical retetion and seal
What is the key ingredeitn in MTA and Endosequence
Calcium Silicate
Calcium silicate based cements such as MTA and Endosequence release what upon setting?
Calcium Hydroxide
What is the advantage of Calcium Hydroxide on the pulp
Antibacterial and promotes bony and dentine tissue formation
What are two disadvantages of Calcium Silicate based cements
Difficult handling, long setting time, stains teeth
Why are news materials like MTA and CaSi cements superior to plain Calcium Hydroxide for vital pulp therapy?
Sealing ability (don’t wash away and permit bacterial re-entry)
What pulp diagnoses allow indirect pulp capping?
Clinically healthy or Reversible pulpitis
What pulp diagnoses would permit direct pulp capping?
Clinically health, reversible pulpitis or irreversible pulpitis (severity dependent)
What is the protocol for direct pulp capping?
Establish haemostasis with NaOCl and pressure, then CaSi cement over pulp (1-2mm thick) then GIC over that (1-2mm thick) then definitive restoration.
In what situation must you do total caries removal
RCT needed, or indirect restoration needed
VPT: If you expose a pulp and can’t achieve haemostatis in under 5 minutes, what do you do?
Remove more tissue, then give it another 5 minutes, then proceed with pulpotomy followed by CaSi and CR. If you still can’t get haemostasis, RCT or Exo
What are the indications for RCT or Exo
- Apical pathology
- Necrotic pulp
- Symptomatic irreversible pulpitis
- Irreversible pulpitis unable to achieve haemostasis for VPT
Why wouldn’t VPT be successful?
- Incorrect initial diagnosis
- Inadequate seal
What is the difference between reactionary dentinogenesis and reparative dentinogenesis
- Reactionary - odontoblasts sense demineratisation of dentine (matrix proteins being released) and descends toward the pulp and lays dentine
- Reparative - primary odontoblasts are damaged and necrose. Ectomesenchymal cells differentiate into odontoblast-like cells and create a different type of dentine. Repair so no tubules.
Why is it important to prepare to within 0.5 to 1mm of apical constriction?
Generally there are lots of bacteria and biofilm in the apical third. It is important that we prepare into this region to enlarge it sufficiently for irrigants to reach.
Why are irrigation needles side vented?
To prevent apical extrusion.
Means irrigant only goes 1mm past needle tip at best!
How should you perform a watch winding motion?
180 degrees clockwise then anticlockwise with slight apical pressure.
Does watch winding cut?
No.
Use Balanced force technique to cut.
What is balanced force technique/
- Quarter turn clockwise
- Maintain apical pressure
- full turn anticlockwise
- Will cut
What size files should you use for watch winding
8,10,15
Working length should be taken from a stable reference point. What is the ideal point?
A reduced cusp
Why is recapitulation important? (4)
Passing a small file to full WL between each working file helps to:
- Smooth steps
- Prevent blockages
- Maintain length
- Keep irrigant moving - removing debris from walls and bringing into solution
What is anti-curvature filing?
Filing away from inner curve
What does Sodium Hypochlorite do? (NaOCl)
- Kills bacteria
- Lubricate canal
- Dissolve pulp tissue
What strength NaOCl should be used for antibacterial effect in the pulp?
0.5% to 5%
Has same antibacterial effect but lower strength less effective at dissolving tissue
What should you do if you cant get the irrigant to length?
Prepare and taper the canal - makes path for irrigation.
Provided it’s not going out the apex you can’t use too much.
What is in Odontopaste?
- Clindamycin
- ZnOE
- Triamcinolone (steroid)
What length do you need to get to before doing any coronal preparation?
At least 13mm
List the cells found in the pulp:
- Odontoblasts
- Undifferentiated mesenchymal cells
- Fibroblasts
- Macrophages
- Lymphocytes
- PMNs
- Immunocompetent dendritic cells
What makes a pulp ‘vital’
Blood flowing through the pulp
What are the two causes of the reduction in pulp size
- Age (secondary dentine)
- Wear
It is generally agreed that the pulp can survive if there is only …..mm of dentine remaining over it.
0.25mm
Why does trauma often result in necrosis of the pulp in adults?
Blood supply through the apex is cut off
Which tooth has the largest pulp chamber?
What rate is secondary dentine laid down
0.8 microns per day
When might you see reparative dentine as opposed to reactionary
Injurious prep or pulp exposure
On average pulp areas in sectioned clinical crowns are what % larger than radiographs suggest
23%
Do instruments in the pulp come into intimate contact with the trigeminal nerve?
No. The pulp is just an innervatted connective tissue, like the PDL.
Blood only occupies about what % of the health pulp space
5%
It is generally agreed that the pulp can survive is there is mm of dentine remaining over it.
0.25mm
Which is most important to pulp survival:
a) Dentine thickness
b) Bur speed
c) Cavity conditioning
d) Filling material used
a) dentine thickness
Why it important to replant a young tooth as soon as possible
To restore blood flow to permit rest of apex to form
The most important factor in succes when wanting pulp to survive is:
Ability to arrest haemorrhage
What are the two main bacteria involved in caries
Strep mutans
Strep Sobrinus
Pain on percussion before endodontic treatment indicates:
a) reversible pulpitis
b) irreversible pulpitis
c) pulp necrosis
d) inflamed periodontal tissues
e) exposed dentine
d) Inflammed periodontal tissues
The walking bleach technique:
a) Uses heat treatment
b) requires patients to report in 24 hours
c) can be done in poorly obturate canals
d) uses mixtures of sodium perborate and 3% hydrogen peroxide
d) tooth stain remover (hydrochloric acid)
d) Uses mixtures of sodium perborate and 3% hydrogen peroxide
The most appropriate irrigant for a permanent tooth with an open apex is:
a) LA solution
b) 1% NaOCl
c) 5.25% NaOCl
d) 2.5% NaCl
e) 0.2% CHX
b) 1% NaOCl
A 12 year old boy presents with a complicated fracture of his 21 following a rugby tackle. There is no lateral luxation but the tooth is sensitive to hot and cold. You take a history and 2 PA radiographs at different angles. Sensibility testing gives a delayed response. The most appropriate management for the 21 at this appointment is:
a) Pulpectomy immediately as the tooth will become non-vital
b) Partial pulpotomy with MTA and follow up in 6 months to a year
c) Direct pulp cap with GIC and follow up in 6 months then 1 year
d) Partial pulpotomy with MTA and follow up in 6 weeks
e) Direct pulp capping with CaOH and pulpectomy after 7 days as the tooth will become non vital
d).
Direct pulp capping is not appropriate in this case as will be dirty.