Obturation Flashcards
why obturate?
seal portals of entry apically, laterally, and coronally
when do we obturate?
- root canal system is adequately cleaned and shaped and s of such size and shape to accomodate the filling material and/or technique of choice
- RCS is DRY
- there is NO FOUL ODOR
- tooth is NOT SYMPTOMATIC
where do you fill/obturate to?
The cemento - dentinal junction
radio graphic apex
what do you fill?
as much of the root canal system as possible
- the main root canal
- lateral/accessory canals
- fins and isthmuses
what material are we using to fill?
gutta-percha and sealer
what opacity should root filling material be?
radio-OPAQUE
what are the components of gutta-percha?
20 % gutta percha
65% zinc oxide
10% metallic salts
5% waxes
what are the two size of GP we are using?
- fine medium
2. medium
Gutta percha disadvantages
- lack of rigidity
- lack of length control
- lacks adhesive quality
- shrinkage
what happens to gutts percha as it cools? what phase?
it shrinks
shrinkage occurs when go from alpha phase to beta phase
alpha phase is 42-44 celcius
beta phase is 37 degrees celcius
describe sealers
they aid in establishing a good seal
they serve as a filler for canal irregularities and minor discrepancies between root canal wall and core filling material
they also seal lateral and the accessory canals and assist in microbial control
they can act as lubricants for the GP
acceptable types of sealers?
- ZOE based
- zinc eugonel
* *one we use
- powder is zonc oxide and liquid is the eugenol - CaOH based
- Resin based
why cant you just use sealer?
it will dissolve in body fluids over time (months)
the GP and sealer together cause an intimate associated b/w the mixture and the canal walls to create the seal
ideal properties of root canal sealers
- tacky when mixed to provide good adhesion berween it and RCS when set
- Hermetic (air tight seal)
- RADIO-OPAQUE
- very fine powder so can mix easily with liquid
- doesn’t shrink when setting
- want it to be
liquid component of sealer
Eugonel
- 4-allyl- 2 methoxypheno
- balsam resin and water
- eugenol
- oil of clove
how do we at BU obturate
Warm vertical compaction
- the multiple wave compaction SCHILDER TECHNIQUE
Acceptable methods of obturation
- Lateral compaction
- carrier based compaction
- hydraulic compaction
- warm vertical compaction
Acceptable methods of obturation
- Lateral compaction
- carrier based compaction
- hydraulic compaction
- warm vertical compaction
describe lateral compaction
adding multiple GP cones and compacting them together
they are ‘cold-welded’ together but there are still gaps between many points which must be filled with sealer
describe carrier based compaction
put in a heated carrier which appears to make it easier but actually technique sensitive and hard to retrieve and difficult to prepare a post space with
describe hydraulic compaction / condensation with bioceramic sealer
sealer that is biocompatible
- non toxic
- doesnt cause irritation if extrusion occurs
- forming bond with dentin because forms hydroxyapatite during setting **
- hydrophilic
but it is expensive and very hard to retreat or creae a post space with
it is also not a 3D fill in large canals
two techniques in warm vertical compaction?
- multiple wave compaction
- Schilder Technique - Continuous “SINGLE” wave compaction
- buchannan Technique
why do we compact?
to compensate for shrinkage of gutta percha
how do we avoid loosing seal when doing warm vertical compaction?
since GP shrinks upon cooling from 42 degrees, any seal gained by heating threatens to be lost via shrinkage unless the ,material is COMPACTED to compensate for this shrinkage
general description of warm vertical compaction
involves the application of heat and pressure to compact GP
involve two steps :
- down - pack
- back fill
9 pluggers range from what sizes?
8 8 1/2 9 9 1/2 all the way to 12
tip diameters of pluggers that correspond to the associated plugger
8 = .4 mm 8 1/2 =.5mm 9 = .6 mm 9 1/2 = .7 mm 10 = .8mm 10 1/2 = .9mm 11 = 1.1 mm 11 1/2= 1.3 mm 12 = 1.5 mm
two things you need to apply before doing cone fit?
- EDTA in canal - this solution must remain in canal for a minimum of 1-2minutes in order to remove the smear layer
- place cone in NaOCL for 60 seconds to disinfect the cone before fitting
how do you selec master cone?
select cone that is the same taper as the last instrument used at working length
- need to feel A TUG BACK at the area of the apex
if it does not go to working length it is too large
how much of gutta percha do you coat with sealer?
the apical 3mm
when heat hits GP how much farther from where it touches will it also heat?
about 3mm or so beyond
first pluggers shuold be what size ?
big because you’re at the coronal aspect
what is a hotshot used for?
a GP gun for the back fill
has 20, 23, or 25 gauge needles
what did one study determine the maximum temperature bone could withstand before death of osseous cells?
occurred at 47 degrees celcius
IF YOU CAUSE A TEN DEGREE OF CHANGE YOU COULD BURN IT – cause damage to the PDL cells
- But touch n heat usually only changes it about 2-3 degrees
so studies have shown 3-4 seconds at 200 degrees farenheit are safe for most teeth
what is the critical increase in the PDL before IRREVERSIBLE damage is sustained
10 degrees Farenhieit
before sealing the access cavity (after obturation) what do you need to make sure?
it is asymptomatic, no discoloration, no pain, no clinical signs of failure like sinus tracts,
