lecture 3: obturation Flashcards
goals of obturation
- eliminate all avenues of leakage from the oral cavity into the RC system or out of the RC system into the periodontal or oral tissues
- seal within the RC system any irritants that cannot be fully removed during canal cleaning and shaping and prevent their leakage out to the peri-radicular tissues or leakage of saliva or other contaminates into pulp system
rct success depends on thoroughness of ____ and _____ the canal system including ____
- removal of irritants
- quality of seal of
- coronal restoration
obturation materials
gutta percha
qualities of gutta percha for obturation
- can be softened by heat and solvents
- if heated sufficiently, will change phases
- following softening shrinks
- GP by itself does not seat
- must consider sealers
GP can exist in which isomeric forms
- alpha phase (42 to 44)
- beta phase** (below 42)
- amorphous melt (56 to 64)
6 standards of case for RC obturation:
- avoidance of gross overextension into the periapical tissues (GP and Sealer)
- minimal sealer beyond apical constriction
- no under-fillings in the presence of a patent canal
- GP positioned 1mm short of the canal exit
- totally filled with gutta percha and sealer want no voids
- radiograph shows dense filling
what are acceptable obturation techniques
- cold lateral compaction of GP
- hydraulic obt technique
- warm vertical compaction
what is compaction
the secret to CLC-GP obturation success.
Fill must be dense and free of voids and have a THIN sealer layer to be effective.
when are we ready to obturate
- when free of all signs and symptoms of infection/inflammation
- asymptomatic
- tooth is cleaned and shaped to facilitate obturation
- tooth isolated to prevent contamination during obturation
- comfortable and master cone fitted and XR
- root canal is dry
- DST is healed
if the pt is still in pain or the original symptoms have not abated, obturation of the RC ____ resolve the pts symptoms
will not
GP master cone fitment
- select proper size 0.02 ISO gp cone
- use gutta gage to confirm gp size is correct
- gently insert in WET canal until resistance is felt near apex (NaOCl simulates the lubricity of sealer)
how do we select which size gp cone to use
match the MAF
different sizes of GP cones
- all are 0.02 taper gp cones
- #.15/.02 to #.50/.02 up to #100+ as used for CLC-GP
make sure to “mark” on your GP cone what
exactly to your reference point
in the apical region how does the master cone fit
- it only needs a slight frictional fit
- this permits deep spreader penetration between the gp and the canal wall
if the master cone is too small
- cone is too small in diameter and distorts “crickles” near apex.
how does a properly fitted cone fit
- has an immediate fit at WL with NO spaces and no crinkling
CLC-GP: Master Cone Fitment and WL
- MC should NOT extend past working length
- it should STOP at WL
- MC must NOT be able to be pushed beyond WL (tap on it to make sure)
if the MC is NOT tight at WL what should you do
or if it pushes longer
GET A BIGGER MASTER CONE
if the MC is too large
-MC is too large coronally or canal taper is insufficient and will not seat at WL
MC should bind only at
the WL, the fit should be intimate at WL
the importance of master cone radiograph
- this is the last chance to correct a problem easily (without re-treatment)
CLC - GP
=Cold Lateral Compaction Gutta percha
how to select which finger spreader you want
- select root canal spreader that will fit to within 1mm of WL
if it the finger spreader doesn’t go to the WL what does that mean
- you didn’t create sufficient space via your prep or SSB
what is the purpose of finger spreaders
to compact the MC gutta percha in the canal to create space for more gutta percha accessory cones to accomplish a dense fill and thin film of sealer on the canal
steps of lateral compaction include
inserting the plugger to 1-2mm and removed and add an accessory cone is placed in the space created, repeat.
before searing off GP what should you do
- take a confirmation “tree” film
- “tree” stage is the last change to easily remove GP fill if inadequate
what is the only way to retrieve inadequate fill after burn off
through retreatment.. which often leaves the GP beyond apex in bone.
Until bio-ceramic, bio-active sealers came into play what happened
-no sealer was ideal
Until bio-ceramic, bio-active sealers came into play what did all sealers do
they shrank upon setting
and dissolved in body fluids over time
benefits of bio-ceramic sealers
- do not shrink
- do not dissolve
- are BIO active
- it provides viability to the hydraulic “single cone” technique which will be taught in addition to Cold Lateral Compaction
- GP is only necessary here primarily as a source of hydraulic sealer compression/flow and a route to re-treatment or post should either become necessary
overview of hydraulic technique
- same criteria to be ready to obturate
- prepare as usual
- clean and dry canal following EDTA and NaOCl
- Select an 0.04 GP Cone and fit to WL and Radiograph
- Fill canal with BC Sealer using delivery tip
how to fill canal with BC sealer
- place additional sealer from delivery tip on the apical half of the GP cone
- place GP gently in the root canal
- may dart additional GP cones in irregular (wide) canals prn.
- Sear off as per CLC-GP technique
- Beware of possible sealer getting into mandibular canal on mandibular pm and m
what do yo do with a WIDE type II canal
- you pick the easiest canal to fill to WL
- the second canal will merely merge into the 1st at some point short of WL
how to control the apical constriction
- do NOT take any instrument larger than your patency file beyond WL. Look at your rubber stop.
- take care to NEVER go beyond WL with any SHAPING instruments
- if an apex is open, you should use CLC-GP instead of single cone
restorations for pm and m
-pm and m require crowns in all cases to prevent VRF
restorations for ant
- ant tetth with minimal loss of tooth structure may need only a composite restoration to restore RCT
what should you use with a bc sealer ***
GP ***
when should you operate **
when canal is dry and the patient has remained asymptomatic ***
lateral compaction uses what ***
uses 0.02 GP cones and needs finger spreaders (aka compaction) ***
tug-back is needed
hydraulic obturation technique uses what
uses a 0.04 GP gone and BC sealer
no tug-back is needed ***
where should you sear GP
below the CEJ, clean the pulp chamber and seal the canal with GI
what methods and materials are not acceptable
- silver points
- paraformaldehyde-containing pastes
- any “conventional” paste only obturation is doomed
what is involved in obturation?
- cleaning and shaping and disinfecting the pulpal system but also SEAL all PORTALS OF EXIT and all potential portals of exit.
apically, laterally and coronally. Leakage of anywhere will contaminate and compromise the RCT.
what is the #1 cause of RCT failure following successful tx
Leakage of coronal restoration
definition of a good obturation
a dense, homogenous seal from the CEJ to the apical constriction in all canals
what is gutta percha?
- gp comes from trees, now made synthetica,ly
- trans-polyisoprene (an isomer of latex)
composition of gutta percha
- gutta percha
- zinc oxide (59-76%)
- waxes, resins, coloring agents
- metal sulfates
what does GP require
a sealer
the ideal gp sealer
- compatibility
- inertness
- tissue tolerance
- inexpensive
- malleable
- relatively easy to work
- useful in many techniques
what you dont want for a gp sealer
- notoriously poor seal
- expands and contracts with solvent and temperature
- will also change phases with sufficient variation in temp
