BDS2 Endo Flashcards
Contraindication to endo
CVD last 6mths
Endo risks
- Perforation
- Instrument separation
- Sodium hypochlorite
- Failure to eliminate infection requiring further tx
- Pain, bleeding, swelling
Name examples of cavity base sealers
- Zinc phosphate
- CaOH
- RMGI - vitrebond
CaOH disadvantages
Cytotoxic - kills pulp cells
Design principles of chemomechanical disinfection (3)
- Create a continuously tapering funnel shape
- Maintain apical foramen in original position
- Keep apical opening as small as possible
Function of mechanical prep
Create space for irrigants to eliminate microorganisms
Functions of NaOCL
- Antimicrobial activity
- Dissolves pulp remnants + collagen
- Dissolves necrotic + vital tissue
- Helps disrupt smear layer
Factors important for NaOCL function (6)
- Concentration
- Volume
- Time
- Contact
- Exchange
- Mechanical agitation
What is used to remove the smear layer?
17% EDTA
Disinfection protocol
3% NaOCL 30ml 10 mins
17% EDTA 1 min rinse
Dry between (or brown precipitate formed)
3% NaOCL final rinse
Define EWL
EWL at which instrumentation should be limited
Coronal ref point - apex 1mm
Define CWL
Length at which instrumentation + obturation should be limited
Use apex locator
What is a master apical file?
Largest diameter file to WL
Represents final prep size of apical portion of canal
When do we use a barbed broach?
Extirpate pulp
When do we use a Hedstrom file?
Re-RCT to remove GP/fractured instruments
Properties of a material used to fill RC
- Biocompatible
- Dimensionably stable
- Unaffected by tissue fluids
- Insoluble
- Radiopaque
- Non supportive of bacterial growth
Constituents of GP
- Zinc oxide
- Radiopacifiers
- Plasticisers
Examples of obturation
- Cold lateral compaction
- Warm vertical compaction
Properties of ideal sealer
Bacteriostatic
Non staining
Radiopaque
Slow set
Easily mixed
Name some common sealers (3)
- Zinc oxide
- GI
- Calcium Silicate
Laws of symmetry
Orifices equidistant from line drawn in m-d direction
Orifices lie perpendicular to line drawn in m-d direction across centre of floor + pulp chamber
Law of colour
Colour of pulp floor darker than walls
Law of orifice location
- Orifices always located at junction of walls + floor
- Orifices located at angles in the floor - wall junction
- Orifices located at terminus of root development fusion lines
Method for removing insoluble resins
Ultrasonic
Method for removing GP
Hedstroem handfiles
Reciproc/protaper
Method for removing soluble resins
Hedstroem handfiles
Reciproc/protaper
How to use protaper to Retx
D1 for coronal 3rd
D2 for middle 3rd
D3 for apical 3rd
Name symptoms of NaOCl extrusion (5)
Pain
Swelling
Eccymosis
Haemorrhage
Airway obstruction
Risk factors for NaOCl extrusion (5)
- Excessive pressure during irrigation
- Needle locked within canal
- Loss of control of WL
- Larger apical diameters
- Proximity to sinus
Management of NaOCL
Stop
Keep calm alert pt + reassure
Pain give LA block
If profuse bleeding through RC allow until haemostasis
Steroid containing medicament placed in RC ensure no pressure
Do not obturate but seal to coronal access cavity
Priority to pain relief, dec swelling
Cold compress first few days
Warm for soft tissue swelling
Analgesics
Review within 24hrs
Antibiotics
Refer if severe
Measures to avoid NaOCl accident
- Bib + eyewear
- Dam
- Test dam with CHX
- Syringes labelled
- Always use leurlok 27G needle
- Fill syringe 3/4
- Use silicone stop
- Pass syringe behind pt head
- Depress with index finger
