obturation of rct system Flashcards
importance of obturation
study by Ingle et al (1965) indicated 58% of failures due to incomplete obturation
APICAL SEAL is usually a problem
filling of the system should
prevent the passage of microorganisms and fluid along the root canal and to fill the whole canal system
Not only block the apical foramina but also the dentinal tubules and accessory canals
working length for obturation
prep should end at the junction of pulpal and periapical tissue
should be really close to CDJ = the narrowest part of the canal = apical constriction
wl radiographically determined
Distance is from 0-3 mm
Varying constriction anatomy
Increasing with age
Root resorption is a complicating factor
If filled to apex then over-filled?
filling should happen when
after the completion of root canal preparation and when the infection is considered to have been eliminated and the canal can be dried
timing of obturation
signs
symptoms
pulp status
periapical status
difficulty
patient management
gutta-percha
Most common core material
One of oldest dental material in use today
Produced from juice of trees of the sapodilla family
Natural rubber and gutta percha are polymers of same monomer - isoprene
Trans isomer of polyisoprene
GP presentation
20% Gutta-percha
65% Zinc Oxide
10% Radiopacifiers
5% Plasticizers
gp cold lateral compaction
Most commonly taught and practiced filling technique
Regarded as the benchmark against which other obturation techniques are evaluated
Low cost and ability to control the length of the fill
Potential problems:
Voids, spreader tracts, incomplete fusion of gutta-percha cones, and lack of surface adaptation
size-matched GP cones
Sized-matched cones complement file size and shape
Leave very little space for accessory cones
Is this a single point obturation technique?
warm vertical compaction
Schilder introduced this as method to achieve three dimensional obturation
Required a continuously tapering funnel and minimal apical diameter
SET IT WITH HEAT, SO SEALER TRAVELS THROUGH
use a GP plugger
gives 3D
progressed to continuous wave obturation with new machines
also carrier-based obturation for long canals
disadvantages of thermal techniques
apical control -> can dislodge into maxillary sinus
if we are not in control
use biodentine, MTA
they fill more complex spaces
is the evidence watertight?
“It is clear that sealability studies comparing endodontic procedures using the penetration of dyes, chemicals, etc. are not useful to endodontic science and the Editorial Board has agreed to restrict publication of sealability studies using these techniques.”
resilon
Resin-based system
Dentine bonding technology
Thermoplastic synthetic polymer based on polymers of polyester containing bioactive glass and radiopaque fillers
“Mono-block”
sealer functions
seals space between dentinal wall and core
fills voids and irregularities in canal, lateral canals and between gutta-percha points used in lateral condensation
lubricates during obturation
properties of an ideal sealer
Exhibits tackiness to provide good adhesion
Establishes a hermetic seal
Radiopacity
Easily mixed
No shrinkage on setting
Non-staining
Bacteriostatic or does not encourage growth
Slow set
Insoluble in tissue fluids
Tissue tolerant
Soluble on retreatment
zinc oxide eugenol-based sealer
zinc Oxide effective antimicrobial and may afford cytoprotection
resin acids affect lipids in cell membrane thus strongly antimicrobial/cytotoxic
although toxic, may overall be beneficial with longlasting antimicrobial effect combined with cytoprotective effects
free eugenol which remains can act as an irritant
lose volume with time due to dissolution – resins can modify this
glass ionomer sealers
Advocated due to dentine bonding properties
Minimal antimicrobial activity
Greater solubility
Removal upon retreatment is difficult
Little clinical data to support use
resin sealers
e.g. AH plus
Long history of use – development of AH26
Epoxy Resin
Paste-Paste mixing
Slow setting - 8 hours
Good sealing ability
Good flow
Initial toxicity declining after 24 hours
e.g. EndoRez is a UDMA resin-based sealer
Hydrophilic
Good penetration into tubules
Biocompatible
Good radio-opacity
calcium silicate sealers
High pH (12.8) during the initial 24 hours of the setting
Hydrophilic
Enhanced biocompatibility
Does not shrink on setting
Non-resorbable
Excellent sealing ability
Quick set - three to four hours – requires moisture
Easy to use
sealer warning
Sealers containing organic materials such as ALDEHYDES are not recommended.
assessment of obturation
BASED ON POST OP RADIOGRAPH
Primarily based on post-op radiograph
Length
Taper
Density
Gutta-percha and sealer removal to facial CEJ in anteriors and canal orifice in posteriors
Somewhat subjective
Errors of obturation may be corrected
filling of the RCT system
the tooth should be adequately restored after root canal filling to prevent bacterial recontamination of the root canal system or fracture of the tooth.
coronal seal versus apical seal
“Technical quality of coronal restoration significantly more important for apical periodontal health than the technical quality of the root canal treatment”
orifice closure
Finish obturation at orifice or just below orifice level
IMPORTANCE OF CORONAL SEAL
Gutta percha rapidly becomes infected if exposed directly to oral bacteria
ZnO/Eugenol materials are cytotoxic and form effective antibacterial barrier
RM-GI or flowable composite
verdict on obturation
Complete obturation contributes to success
Assays not always reliable or relevant
Outcome studies important but not uncomplicated
Anecdotal evidence often has been adopted
Classic materials have stood the test of time
Given the diagnosis of Internal Root Resorption, what method of obturation do you think would be most appropriate?
MTA
Not only would it allow complete obturation of the resorptive defect, if there were any communications with the PDL it would present a bioinductive surface to enable healing.
the features of an obturation that should be assessed in a post-operative radiograph.
length
taper
density
what materials can be used for orifice closure following obturation?
RMGI
