Endo Flashcards
When would you root canal teeth with healthy pulps?
- If tooth can’t be restored without seriously endangering pulp
- Tooth cannot be restored without using pulp chamber and canal system to retain restoration (post)
- There is intractable dentine hypersensitivity
On what teeth are RCTs not possible?
- Gross caries
- Vertical fracture
- Advanced perio disease
How can you help teeth to not fracture during treatment?
Flatten cusps or matrix band around tooth
Why is shaping done?
To enlarge the original canals for:
- Mechanical cleaning
- Irrigant exchange
- Ease and control of filling
After access what are the stages of canal preparation and filling the canal?
- Find electronic working length
- Establish glide path
- Coronal flare
- Confirm WL
- Deep flare
- Apical stop preparation
- Irrigation
- Master GP point
- Cold lateral condensation - spreader and accessary points
- Cut off and warm compaction with plugger
What burs are used in access cavity preparation?
- Medium tapered diamond
- Endo Z and Batt bur (safe ended for unroofing pulp chamber)
- Gooseneck and LN pin burs (for locating pulp spaces and canal entrances)
What is a Gates Glidden bur used for and how do you know its size?
Slow speed for canal preparation
Bands on shank
Flame shaped bur
What are barbed broaches made of and what way to twist?
Stainless steel
Clockwise engages and removes pulp
For the ISO hand files, what is the length, taper and diameter of the active part of the file?
16mm
0.02mm/mm taper - 2% taper
Depends on ISO size e.g. ISO 35 = 0.35mm
When were the ISO regulations?
1961
What is the cutting motion for
a) ISO K hand files
b) ISO Hedstroem files?
a) Rotation - watchwind or balanced force motion. Rasping - filing on outward stroke
b) Rasping not rotation. Milled to have a sharp angle so aggressive but fragile
For the non ISO Protaper hand files/ engine driven rotary files, what is the tip size and taper of Shaper 1 (Purple)?
0.17mm
2-11% taper
For the non ISO Protaper hand files/ engine driven rotary files, what is the tip size and taper of Shaper 2 (White)?
0.2mm
4-11.5% taper
For the non ISO Protaper hand files/ engine driven rotary files, what is the tip size and taper of Finisher 1 (Yellow)?
0.2mm
7% taper
For the reciprocating files (Reciproc, WaveOne) what is the tip size, taper and max diameter?
25
8% taper in apical 3mm, 4% taper in remainder
1.05mm
What materials can be used as lubricants and chelating agents?
a) EDTA/ peroxide paste (glyde)
b) Medicated soap (hibiscrub)
What materials can be used as irrigants?
a) Sodium hypochlorite (NaOCl) 0.5-5% - kills microorganisms and dissolves organic matter but must have seal on rubber dam
b) Chlorhexidine gluconate 0.2-2% - antimicrobial but no solvent action
c) Sterile saline or local anaesthetic - flushes debris and lubricates but no other action
What is the reason for antimicrobial dressings?
- Clean and disinfect canals between appointments
- Kill microorganisms that leak around temporary dressings
- Prevent pain after canal prep
What is it called when there is disruption of perfusion that causes pulp death?
Ischaemic pulp necrosis
In reversible pulpitis, what fibres cause pain? and in irreversible pulpitis?
A delta
C fibres
What is the success rate of RCT in necrotic pulps for healing AP?
70-90%
How does AP occur?
Necrotic pulp - toxins leak into PA tissues, host inflammatory and immune defenses cannot enter tooth but attempt to contain infection - bone loss consequence
Why do we use a rubber dam?
- Prevents saliva entry to tooth
- Protects airway
- Allows use of strong disinfectants
- Retracts cheeks and tongue
- Stops pt talking/rinsing
- Improved pt comfort?
What pH is non-setting calcium hydroxide paste? How long does it last? What else can be used? How are they placed?
pH11/12. 3 months
Odontopaste (steroid/antibiotic paste)
File rotated anticlockwise
What allergy should you check for before placing gutta percha?
What sealer cements are used with gutta percha?
Latex
ZOE, resin, silicone, calcium silicate etc
What is the disadvantages of using zinc oxide eugenol sealers in root canal filling?
- Can stain teeth yellow
- Can interfere with composite restorations (inhibits polymerisation so no direct contact)
What sealer is widely used for root canal fillings? What is its setting time?
Resin (AH plus). 8 hours (slow)
What qualities should the temporary filling have?
- Cotton wool to secure canal orifices
- No whisps of cotton wool exposed
- 3 mm thick
- Well adapted to cavity wall
What temporary filling materials can be used in retentive, non-load bearing areas?
Cavit
Sedanol (clove taste)
What temporary filling materials can be used in load-bearing areas?
GIC - good for unretentive
Intermediate restorative material (IRM)
For maxillary central incisors
a) What is the average length
b) How many canals
a) 23.5mm
b) 1
For maxillary lateral incisors
a) What is the average length
b) How many canals
a) 22.5mm
b) 1 canal - distal curve apex
Fishtail shape pulp horns
For maxillary canines
a) What is the average length
b) How many canals
a) 26.5mm
b) 1
Candle flame shape pulp horn
For maxillary first premolars
a) What is the average length
b) How many canals
a) 21mm
b) 2 roots and 2 canals in 90%
For maxillary second premolars
a) What is the average length
b) How many canals
a) 21.5mm
b) 1 canal in 60%
2 pulp horns
For maxillary first molar
a) What is the average length
b) How many canals
a) 21mm
b) 4 in 60%, 3 in 40% (palatal, distal and 2 MB)
When preparing the access cavity for a maxillary first molar, what should be preserved?
Mesial marginal ridge and transverse oblique ridge (no pulp horns underneath)
For maxillary second molars
a) What is the average length
b) How many canals
a) 21mm
b) 3, but 2 MB in 10%. DB canal entrance more central than first molar