Y3 L6 Root canal filling Flashcards
What are the ESE objectives of obturation?
To prevent the passage of microorganisms and fluid along the root canal and to fill the whole canal system, not only to block the apical foramina but also the dentinal tubules and accessory canals.
What are the main objectives of obturation?
- Prevent microbial growth of remaining microorganisms in the root canal space
- Seals the pulp chamber and root canals to prevent microorganisms from entering the canal system via the apical foramen (1), lateral canals (2), furcation canals (3) and patent dentinal tubules (4)
What are the goals of obturation?
- Homogenous (one root filling mass)
- Appropriate length, corresponding to the end point of the preparation, no canal space visible beyond the end point of the root canal filling
- No voids between canal wall and canal filling
- Should extend within 2mm of the radiographic apex
What is the quality of an obturation dependent on?
- Canal anatomy and complexity of the canal system
- Materials and techniques used
- Shape obtained with the canal preparation
- Skill and experience of the operator
How may canal anatomy differ/affect obturation?
- Complex anatomy, number of roots/canals
- Canal shape, curvature, isthmuses, apical deltas, lateral canals
- Physiological changes, younger children with wide canals and open apices, pulp stones
- Calcifications of dentine
- Root resorption affects apical anatomy
- Smear layer and dentine powderaccumulation blocking the canal
- Iatrogenic damage from previous RCT e.g. zips, ledges, perforations
- Fractured instrument removal or bypass
What is the smear layer?
- A layer of organic and inorganic debris
- Instrumentation leaves a smear layer begind
- Should remove before obturation
- EDTA and NaOCl
What are the ESE requirements for a root canal filling?
- Biocompatible
- Dimensionally stable
- Able to seal
- Unaffected by tissue fluids (insoluble)
- Non-supportive of bacterial growth
- Radio-opaque
- Removable from the canal if retreatment is required
Additionally, they should be: - Adherent to dentine
- Plastic on insertion and then solidify
- Inexpensive
- Long shelf-life
- Antimicrobial
- Non-toxic
- Non-staining
What are the main obturation materials used?
- Sealers/cements
- Semi-solids e.g. Gutta-Percha
- MTA
What are the functions of sealers and cements?
- Used to lute semi-solid materials to canal wall
- Seal anatomical features and minor spaces which the GP can’t fit into
- Antimicrobial
What are the types of sealers used in the UDH?
- Zinc oxide eugenol (Tubi-seal)
- Epoxy resins (AH plus)
Other options (not in UDH): calcium hydroxide, glass ionomer, calcium silicate
Are Tubi-Seal and epoxy resin antimicrobial?
Yes, Tubi-Seal has continued antimicrobial efficacy. Epoxy resin, is antimicrobial whilst it sets.
Describe Zinc Oxide Eugenol (Tubi-Seal) as a sealer material.
- Used on student clinics in UDH
- Acceptable, but sealing property not as good as other sealers
- Easy to handle
- Good antimicrobial properties (mostly due to eugenol)
- Contains known allergens
- Soluble when used in thick layers (not good)
Describe epoxy resin as a sealer material.
- Completely insoluble
- Excellent antimicrobial properties (better than ZnOE)
- Virtually non-toxic when set
- Best sealing ability of all sealers
- Handles well but can set fast, more difficult to handle than zinc oxide eugenol
Describe the mechanism of sealers.
- Removal of smear layer required to open dentinal tubules
- Sealer creates resin tags in tubules creating some mechanical retention
- Also adheres to canal walls, creating bond between walls and gutta percha
What is GP?
- A synthetic latex material
- Fills up majority of canal system
Describe the cold lateral condensation technique.
- Simple, rapid and inexpensive
- Requires a tapered, flared, flowing shape
- From apical gauging we know the perfect size file for the canal, the master GP cone corresponds to this size i.e. size 30 = size 30 master cone
- Check radiographically
- Use finger spreader, add accessory cones
Describe the B/Obtrua system for vertical condensation using GP.
- Catridge of GP placed in top of gun
- Material heated up
- Small needle which comes out the end, placed into canal
- Tip can get quite warm, be careful not to burn patients lips
- When it cools it shrinks slightly so need good sealer
- Can be difficult to control, poor handling if not experienced
Describe MTA as a root filling material.
- Hydraulic calicum silicate cement
- Many uses e.g. MTA plug
- Expensive
- Biocompatible, promotes regeneration of tissues
