Thermal GP Obturation Flashcards
What are the aims of obturation?
Establishment of a fluid tight barrier with the aim of protecting the periradicular tissues from microorganisms which reside in the oral cavity
A hermetic seal is required from the coronal orifice of the canal to the apical foramen at the cemento-dentinal junction
Prevent coronal leakage of microorganism or potent nutrients to support their growth into the dead space of the root canal system
Prevent periapical or periodontal fluids percolating into the root canals and feeding microorganisms
Entomb any residual microorganisms that have survived the debridement and disinfection stages of treatment in order to prevent their proliferation and pathogenicity
Ideal properties of a root filling material?
Easy handling and ample working time Seal canal laterally and apically conforming to the complex internal anatomy Dimensionally stable Non-irritant Does not stain tooth structure Anti-microbial Impervious and non-porous Unaffected by tissue fluid Radiopaque Easily removed
What is gutta percha? What are the forms of GP?
Naturally occurring rubber Occurs in 2 crystalline forms: alpha phase and beta phase - Below 42 degrees = beta phase - 42-49 degrees = alpha phase - Above 49 = GP becomes amorphous Upon cooling it returns to beta phase
What does traditional GP contain?
Zinc oxide (65%) Gutta percha (20%) Radio opacifier (10%) Plasticiser (5%)
What are the roles of an endodontic sealer?
Seal the space between the obturating core material and internal root surface
Fill space between core and accessory filling materials in lateral condensation
Seal irregularities of the complex canal anatomy
Lubricate and facilitate seating of the core and accessory filling material
What are the types of endodontic sealers?
Zinc oxide/eugenol based
- Most popular e.g. tubiseal
Calcium hydroxide based
- Less antimicrobial, but also less toxic than Zn-Ox.Eug e.g. sealapex
Glass ionomer based
- Difficult to remove
Resin based
- Superior sealing ability, adheres to denture and antimicrobial
Calcium silicate based
- Limited research
Silicone based
- Limited research
List the obturation techniques
Lateral compaction (cold and warm) Single cone Thermomechanical compaction Warm vertical compaction (continuous and interrupted wave) Carrier-based Apical ‘barrier’
Cold lateral compaction stages?
Choose an ISO master GP point that fits snugly with tug back
Coat with sealer and place to WL
Place finger spreader down to 1mm from the WL
Place an accessory point where the finger spreader was removed from ensuring it extends to 1mm from the WL
Continue process - finger spreader will get further away from the WL
Continue until the accessory points fill to just below the canal orifice
Once completed, sear cones off at orifice level and compact vertically
Warm lateral compaction?
Uses energised spreading
Technique:
- A K type file is inserted into a peizoelectric ultrasonic unit
- File is activated and introduced into the GP generating heat to soften
- Finger spread placed, then accessory point
Advantage over cold lateral as thermoplastic GP may flow into accessory anatomy
Single cone technique?
Where only the master GP point with sealer is used to obturate
Only applicable with greater taper GP points matched to the preparation file
Not good 3D seal
Not recommended
Thermomechanical compaction?
Uses heat generated from a reverse hedstrom file which is driven with a slow handpiece into the GP
Master point placed with sealer and the instrument placed 3-4mm from the working length
GP is driven apically and laterally and the file driven coronally
Can cause extrusion from the apex and its possible for the instrument to fracture in the canal
Types of warm vertical compaction?
Continuous wave compaction
Interrupted wave compaction
Continuous wave compaction stages?
Downpack
- Aims to create an apical plug of GP which seals and fills the apical 3-4mm of the canal = apical control
Backfilling
- Aims to fill the remainder of the canal by squirting molten GP through a GP gun
Stages of continuous wave compaction?
1 - Choose a GP point which fits the apical prep and has tug back just before the apical constriction
2 - Choose a plugger which extends to approx 4mm from the apex and binds.
Adjust rubber stopper to this length
- Turn on heat source and plunge plugger through the GP point
- Continue to apply pressure towards the pre-determined binding point - done in 1 movement and takes 1-2 seconds
- Plugger will slow its apical movement and stop just short of the predetermined binding point.
Stop heat source and maintain apical pressure for 10 seconds to prevent cooling shrinkage of the mass
6 - Activate heat source again and complete the pressure until the binding point is reached
Wiggle plugger tip and remove it from canal
- As plugger is removed any GP coronal to the tip is also removed leaving a plug of GP sealing the apical 3rd
8 - Place the tip of the injectable GP gun against the plug of apical GP and extrude GP in bursts of 3-4mm
- After each application of GP use a condenser to compact the GP, then place more GP in this manner until canal orifice is reached
- Complete obturation
Advantages of continuous wave compaction?
Has been show to provide improved 3D obturation compared to cold lateral condensation
Canal is filled with a homogenous mass of GP with no carrier
Good for filling internal resorption defects
